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Message started by lbarron on May 2nd, 2007 at 12:29pm

Title: firstlook
Post by lbarron on May 2nd, 2007 at 12:29pm
hey, I have recently purchased a picoscope and have been having a play with the firstlook sensor. When using it in the exhaust and using ignition triggering, can you associate the pulses to the exhaust valve opening and closing? are there any obvious parts of the trace to concentrate on?
thanks
Lawrence

Title: Re: firstlook
Post by Mick on May 2nd, 2007 at 5:22pm
Hi Lawrence

Do you have a psd file to show here? There are some great guys willing to help you with your questions.

you will find every running engine has a different wave. But cranking waves are a little bit easier to interpretate.

Mick

Title: Re: firstlook
Post by romain on May 2nd, 2007 at 6:13pm
Hi Lawrence,

Maybe this will be of some help
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=firstlookusersmanualv3.pdf (656 KB | )

Title: Re: firstlook
Post by mwebb on May 4th, 2007 at 8:54pm
the easiest way to use the first look sensor in the exhaust , FLSE , is to use it with AceMisfireDetective .
AMD does the translation and sees things i can not . but i keep trying .

   dont forget that the exhaust pulse you see does  not match  the cylinder fireing , there is an offset , which truly kicked my butt at first and still does off idle.    

the latest version of ANNO wave from AES wave has the ability to put a transparency with pre marked things over the top of saved waveforms and imho you should build that or something like it into your learning curve .       but there really isn't anything quite like it   paint.net  can also build layers on top of waveforms .... but  i dont want to learn to be a graphics designer to operate it  and it uses gobs of memory to save files  ...

anno wave files wont open here but they can be saved as gif files which do open here .  

my thoughts are to create templates in anno wave to overlay on top of pico 6 captures that cover 720 degrees of engine rotation ... so you can sync on spark or ... and see where things happen in the engine the anno wave template can be expanded and contracted without loosing the relative position of things  noted in it ... to match the 720 degrees plucked out of a larger pico 6 capture ....
                         
   but it has been a little busy
   AMD capture with sticking exhaust valve and ...
   


1980_fiat_cyl_1_exhaust_valve_sticks_open_AMD_misfire_on_2.gif (83 KB | )

Title: Re: firstlook
Post by Mick on May 5th, 2007 at 4:54am
Hi Mike

I was Asked to try out AceMisfireDetective (AMD) and had a hard time loading it to work with my pico 6 The version I had was 1,0 and then was sent an updated version 1.15 (maybe version # incorrect) but My point is I see your version is much higher 2. did you have any problems in the beginning load with lower versions?

I am glad Romain and yourself brought up the offset issue thanks guys

Mick


Title: Re: firstlook
Post by Jeff on May 5th, 2007 at 7:18am
Hi Members,
 This is first attemp to understand the offset.  Not sure really how to read yet.  Trying to understand wich is the exhaust valve.  The link that Romain supplied helped alot (not in the manual I received).  Sure may have tested wrong.  Any help gladly accepted.  Thanks

Jeff
exhaustsync.JPG (127 KB | )

Title: Re: firstlook
Post by Rich Barton on May 5th, 2007 at 7:58am
Hi Jeff:

We all are learning this firstlook tool, it holds a lot of answers and alot of questions ,but it is a good aid in finding problems ;)

Mwebb and Wilf are the best at it I have seen so far. ;D

I am sure there is more people but these 2 are on autonerdz. ;)

they both have different views which keeps us on our toes. :-/

I think I would do cranking test first to learn where the valves are first,then go from there. ;)

Like I said I am training myself on this also ,so what better way to do it than on autonerdz. 8-)

I will put some captures of a F150 with a problem up here later but first I got to move some cars. :'(

Title: Re: firstlook
Post by Jeff on May 5th, 2007 at 8:57am
Hi Rich,
 I will try that, always getting buggy before horse.  Thanks

Jeff

Title: Re: firstlook
Post by Wilf on May 5th, 2007 at 11:12am
Hey guys
I don't have much time
Sneaking a peak during my honeydues
Here are a couple things to think about

Wilf
chev_V8_valve_relationship.gif (165 KB | )

Title: Re: firstlook
Post by Wilf on May 5th, 2007 at 11:24am
Keep in mind that there are 3 exhaust valves open at once
To check for mechanical problems do a cranking test with the throttle wide open
I can do a more detailed version with the exact timing if you like
Need the exact engine cam specs
This is not usually necessary because the exhaust pipe distorts the pulses somewhat anyway

If you do this exhaust test with a 4 cyl it is easier to see since there is only one exhaust valve open at a time
I like to start here to learn because it is so much easier

You can always do your test like you did either running or cranking with one spark plug out and see the result
All engines are a bit different because of different exhaust lengths and bends

Play around
It is a blast

Pretty soon you will be doing it with one FLS hooked to the exhaust and one to the intake and yet another on the fuel rail
Jeffs_exhaust.gif (72 KB | )

Title: Re: firstlook
Post by Jeff on May 5th, 2007 at 12:11pm
Thanks Members,
 Gives a great direction in learning this tool.  Definetly more to it than I first realized.  Thanks

Title: Re: firstlook
Post by Rich Barton on May 5th, 2007 at 6:40pm
Hi Group:


I got an idea , lets take a truck that has a problem and play with it . [smiley=devious.gif]



I just happen to have a truck to play with. [smiley=thumbsup.gif]

I have an 95 Ford F150 5.0 with an engine problem the computer shows misfire in number 7 and 8 cylinder.

The engine has a misfire and a knock coming from around #4 cylinder like  a lifter maybe [smiley=eek.gif]

Here is the pico diagnostics compression test. ;)


Pico_Diagnostics_test_for_Jeff.jpg (65 KB | )

Title: Re: firstlook
Post by Rich Barton on May 5th, 2007 at 6:43pm
Here is a Firstlook test cranking with TP closed. ;)
Firstlook_for_Jeff__Test_2.jpg (59 KB | )

Title: Re: firstlook
Post by Rich Barton on May 5th, 2007 at 6:50pm
Hopfully somebody can fill in the blanks and we will see where we end up. [smiley=ok.gif]

I have not done any compression test or secondary ignition yet but we can the customer does not want to fix but we can learn from this junker. [smiley=eek.gif]

It is really storming here so bare with me as I hold my lap top tight. [smiley=devious.gif]

Here is with TP open cranking ;)
95_Ford_F150_5_0_TP_open_Cranking.jpg (62 KB | )

Title: Re: firstlook
Post by Rich Barton on May 5th, 2007 at 6:53pm
Wilf I know you want the files and more time on the screen I will ,these are just to get us going.

Here is the rag trick in the exhaust.


How does it look.
95_Ford_F150_5_0_Rag_Trick.jpg (65 KB | )

Title: Re: firstlook
Post by mwebb on May 5th, 2007 at 9:58pm
i never had a communication problem with AceMisfireDetective on any version , one version was unhappy and would not record a full 20 screens , it did not like the sync pickup that came with the kit... i dont remember which version .

as a rookie , i have not graduated to 8cyl waveforms yet ...

the overlay is from Tom Clozza's article or discussion about vacuum waveforms .
          every one using the FLS  should read that and Bernie Thompson's article in Motor Mag archive.
         
            i have a copy and i know Wilf has a copy .
here is an overlay on top of a running compression waveform , marking out what happens when , you can make your own by running a running compression test then importing that save into ANNO wave  ,

      DO not use the FLS sensor for running compression , the one i did is with a FLUKE PV 350 ,
         which sux , dont buy it .    useless as mudflaps on a sledghammer . terrible resolution.  

    allow for ignition timing advance and overlay on spark parade to see what intake or exhaust valve is opening when .  
    in ANNO wave you can stretch or shrink or whatever and the overlayed template  image stays in proportion  .

98_bmw_running_compression_marked_ANNO_wave.gif (103 KB | )

Title: Re: firstlook
Post by lbarron on May 8th, 2007 at 1:21pm
hey, here is a simple capture of a 4 cylinder engine, FLS in exhaust and triggered on the common HT king lead. cyl no 4 plug lead is half off as is obvious from the trace. all the valves are in good condition as far as i am aware as this test was performed on my car which runs fine. is there anything characteristic about the trace? surely the exhaust valve opening should be matched by a positive pressure pulse? is this to be expected or do the ocsillations in the pipe mask this?
firstlook_exh_mis.gif (21 KB | )

Title: Re: firstlook
Post by mwebb on May 8th, 2007 at 3:41pm
  my first thoughts were wrong .
         

have you tried using a 10" rubber tube on the FLSe , i made a 10" length starting with 4" of 10mm then 4" of 1/2 " then 4" of 3/4" tube to make what looks kinda like a trumpet ,  to clean up the hash in the exhaust pulses .  

it looks like the misfire signature pulse in the exhaust is delayed because your spark timing is very advanced  ?   how does that look with no loose spark plug wires ?

---------------------------------- firing order  1342 assumed .  

here is a similar waveform of a ABA 2.0 jetta , #4 wire is pulled back a bit to induce a misfire . the green verticle cursors are inserted at 180 degree intervals to take up 720 degrees to make it easier to see when the exhaust pulse IS happening . i have SWAGed  allowed a little for ignition timing advance .
 
 a new feature in ANNO wave .

i wait now for Wilf to show me my error ....

2_0_ABA_jetta_Ign_misfire_on_cyl_4_5_vert_.gif (111 KB | )

Title: Re: firstlook
Post by mwebb on May 8th, 2007 at 9:37pm
i have taken the liberty to mark off your waveform , i did not label any except the exhaust pulse  

but it would    be     Power  Exhaust  Intake  Compression    180 degrees for each   total 720 degrees
   but the valves open & close near to those #s not at those #s

now i will try to apply those cursors to RB 's 8 cylinder waveform  
4_cyl_IGN_misfire_unknown_Autonerdz_4_vert__001.gif (84 KB | )

Title: exhaust valve operation
Post by lbarron on May 12th, 2007 at 5:07am
Hello, i have been having a play with my firstlook sensor in the exhaust. I am trying to learn which stage in the cycle each pressure pulse is due to. this test was performed on my single cylinder, 4 stroke, yamaha 125cc motorbike. There appears to be one spark for each 360 revolutuion with one spark at the end of the exhaust stroke (the one with the lower firing KVs due to the lack of compression. . .)
This test was carried out under load at medium revs.

Am i right in thinking that the first positive pressure pulse is due to the exhaust valve opening and the pressure created by combustion being expelled into the exhaust pipe?

There is a second postive pressure pulse about 10ms after, is this the pressure created by the piston pushing the spent charge out of the cylinder? this makes sense to me as the second spark fires at the end of this pulse, indicating that the piston is nearing TDC. . .

finally, what do you think about the negative pressure pulse after the two positive ones? is it due to the relaxation of the sensor's  diaphragm, or the inertia of the exhaust in the pipe causing a depression or could they be due to valve overlap? . . .

I get the same characteristic trace at idle but the pressure pulsations are not as high due to the reduced volume of charge in the cylinder.

i thought that this may make the trace easier to dicipher as there are no other cylinders making any contribution to the pressure in the exhaust.

Thanks for any replies,
under_load.gif (17 KB | )

Title: Re: firstlook
Post by mwebb on May 12th, 2007 at 7:32pm
useing the ANNO wave program from AES version 1.5.9
i have included the blocks from the Tom Clozza vacuum article with vertical cursors to mark off each 180 degrees of engine rotation.   one block of
   intake compression power exhaust  shows 720 degrees of engine rotation as marked by the 2ndary spark waveforms .      
   i used the actual start of the exhaust pressure pulse as a reference to line up the blocks .    
125_cc_motorcycle_5_vert_TC_.gif (80 KB | )

Title: cranking
Post by lbarron on May 14th, 2007 at 11:33pm
heres a trace captured from my single cylinder 125cc motorclcle again. (4 stroke)
the firstlook sensor is in the exhaust, triggered on the HT lead. it appears that once the exhaust valve opens, there is a drop in pressure in the exhaust. (a negative pressure fluctuation) is this the case or am i being confused?
in the example of this test given in the Pico software a similar trace is reported.
is this one of the reasons that when you get a missfire, the pressure drops off (neg pressure pulse as the exhaust valve opens?)

thanks again for any light on the subject. . .
crank_open.gif (14 KB | )

Title: Re: firstlook
Post by mwebb on May 16th, 2007 at 11:54am
what is different ? it is not running here ? 400 rpm ? FLSi ?

Title: Re: firstlook
Post by lbarron on May 16th, 2007 at 11:57pm
oops, i left that bit out! this was a cranking test. When you see the drop in pressure, can you confirm that that is when the exhaust valve opens? is the slight rise after the initial drop due to the piston pumping the air from the cylinder? sorry if i seem silly, i just want to ret a solid understanding of which parts of the trace represent which parts of the engine cycle and this single cylinder example simplifies it.
Thanks!

Title: Re: firstlook
Post by mwebb on May 17th, 2007 at 10:13pm
you do not seem silly , none of us were born knowing how to rollerskate and yet somehow we learned .  i rollerskate well but it took me years to learn .   i still fall .

                     mistake here in this image , do you see it ?


you need ANNO wave by AES
125cc_motorcycle_cranking_FLSe_5_vert_anno.gif (69 KB | )

Title: Re: firstlook
Post by lbarron on May 28th, 2007 at 8:25am
this is a trace of a 4 clyinder engine at 2500 rpm. the engine has twin static ignition with the plugs firing 1&4, 2&3. i disabled injector number 4. (firing order 1342)
i used the primary earth for 1&4 plugs, at least according to the wiring diagram i did!
do you rekon this is correct? it almost appears to be a misfire on injector number 2. . .
what do you people think?

i just dont want to get confused over this!!
thankyou
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=2500_inj_miss.psdata (257 KB | )

Title: Re: firstlook
Post by lbarron on May 28th, 2007 at 8:39am
. . .and here is the same car with the same problem viewed at idle, the two traces just don't seem to cohere with each other. . . is there anything obvious that i am overlooking.  . .
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=idle_inj_miss.psdata (260 KB | )

Title: Re: firstlook
Post by mwebb on May 30th, 2007 at 10:20pm

lbarron wrote on :
. . .and here is the same car with the same problem viewed at idle, the two traces just don't seem to cohere with each other. . . is there anything obvious that i am overlooking.  . .



                                     
                          here is my interpretation of SOME of what is going on here .  i dont see where the fuel could have come from that caused the extra pressure in exhaust puff  for cyl #2 unless the injector for # 4 is leaking  .   since nothing was synced i am guessing on the sync . weak exhaust puff = no fuel = disconnected injector on #4 ?  
cyl_4_injector_disconnected_idle_.gif (97 KB | )

Title: Re: firstlook
Post by mwebb on May 31st, 2007 at 8:15pm
here is a screen cap of some of the active cursor options in ANNO wave ,
ANNOwave_active_cursor_.gif (101 KB | )

Title: Re: firstlook
Post by mwebb on Jun 9th, 2007 at 7:38pm
so , here is another thing ANNO wave can do ,
this is relative compression from 4 cylinders stacked up after the size amplitude and length has been adjusted such that they all displace the same amount of screen for 720 degrees .
96_accord_relative_compression_stack_ANNO.gif (79 KB | )

Title: Re: firstlook
Post by mwebb on Jun 9th, 2007 at 7:39pm
and zoomed in on the valve opening and closing events , that is not measured using FLS althiugh i believe the hi pressure FLS sensor can do this , i used a Fluke PV 350 .
96_accord_relative_compression_stack_ANNO_zoom.gif (103 KB | )

Title: Re: firstlook
Post by mwebb on Jun 14th, 2007 at 9:16pm
to Message
it is hard to find actual valve timing specifications , and
sometimes values provided are wrong .
so if you capture a running compression wave form with a
pressure transducer in place of a spark plug , you can use
the active cursor function in ANNOwave to measure exactly
when the valves open and close ,
   to check for and confirm jumped timing components .

of course with out a known good reference it may not be
helpful.  
87_844_valve_timing_how_to_diagram_.gif (35 KB | )

Title: Re: firstlook
Post by rahill on Jun 15th, 2007 at 12:10pm

    That's good Michael. If I were looking for cam timing problems it could be very usable but I wouldn't bet on the the exact timing that shows I think I could work with the symmetry of it though in verifying cam timing with out any problem.
What kind of vehicle is that? What ever it is that cam is ground on pretty narrow lobe centers  with a 100.5 degree displacement angle to be in a passenger car. I seldom see displacement angles this narrow on anything.  Even though it's bottom timing would appear to be installed straight up it's actually installed 2.5 degrees retarded with the intake lobe center at 103 degrees after tdc and the exhaust lobe center at 98 degrees btc.   With 224 degrees duration showing on the intake and 214 on the exhaust I would guess it was at least a 3.0 or larger engine. I wouldn't expect to see much change in the waveform until the valve was a ways off it's seat either.

Title: Re: firstlook
Post by mwebb on Jun 16th, 2007 at 7:58am

Rick Hill wrote on Jun 15th, 2007 at 12:10pm:
    That's good Michael. If I were looking for cam timing problems it could be very usable but I wouldn't bet on the the exact timing that shows I think I could work with the symmetry of it though in verifying cam timing with out any problem.
What kind of vehicle is that? What ever it is that cam is ground on pretty narrow lobe centers  with a 100.5 degree displacement angle to be in a passenger car. I seldom see displacement angles this narrow on anything.  Even though it's bottom timing would appear to be installed straight up it's actually installed 2.5 degrees retarded with the intake lobe center at 103 degrees after tdc and the exhaust lobe center at 98 degrees btc.   With 224 degrees duration showing on the intake and 214 on the exhaust I would guess it was at least a 3.0 or larger engine. I wouldn't expect to see much change in the waveform until the valve was a ways off it's seat either.




that is a 1987 Porsche 944 ,2.5 liter 4 cylinder engine auto trans , red .  basic version . 60k miles . no indications of any problems .  AC repairs underway .

notice the descending value right after TDC ,                does that little dimple belong ? or is that an indication of a problem , leak .  either way it is a minor change that is reflected in the waveform ,
             the piston is moving down,  accelerating , all valves are closed .
                      all the lines should be straight there . no abrupt change s .    ????
                               and yet there it is .

i think that that does show exact valve timing , i find that any change in pressure  shows up right away [see above]  in the waveforms , i was concerned that the engine speed might vary slightly and skew the the values and i cant say that didnt happen but at 2k rpm i think the effect is lessened.

since i selected every other TDC and set that space between to equal 720 degrees , if engine speed changed in the middle my measurements would be inaccurate .   next time i need to add ckp to confirm .

pressure transducers do not usually line up with them selves , they all seem to have some small delay , but if there is only one transducer being used the delay is uniform across the waveform , not a factor .  

Title: Re: firstlook
Post by rahill on Jun 16th, 2007 at 11:57am

Quote:
that is a 1987 Porsche 944 ,2.5 liter 4 cylinder engine auto trans , red .  basic version . 60k miles . no indications of any problems .  AC repairs underway .

notice the descending value right after TDC ,                does that little dimple belong ? or is that an indication of a problem , leak .  either way it is a minor change that is reflected in the waveform ,
            the piston is moving down,  accelerating , all valves are closed .  
                     all the lines should be straight there . no abrupt change s .    ????  
                              and yet there it is .  

i think that that does show exact valve timing , i find that any change in pressure  shows up right away [see above]  in the waveforms , i was concerned that the engine speed might vary slightly and skew the the values and i cant say that didnt happen but at 2k rpm i think the effect is lessened.

since i selected every other TDC and set that space between to equal 720 degrees , if engine speed changed in the middle my measurements would be inaccurate .   next time i need to add ckp to confirm .  

pressure transducers do not usually line up with them selves , they all seem to have some small delay , but if there is only one transducer being used the delay is uniform across the waveform , not a factor .      



Hi Michael
I'm not sure what that dimple is either. Some kind of turbulence right near the plug or could there be some valve leakage? I thought at first it might have to do with piston transitioning from acceleration to deceleration bu it's too early.  That would happen somewhere around 5 ms after tdc I think or somewhere between 60 and 80 degrees atc  depending on rod length to stroke ratio if I'm right in assuming you have 9ms per division up there.

  I agree that in looking at events with a pressure transducer the delay is not a factor as long as we're not trying to compare timing to electrical events or to another transducer and any events in the waveform itself are relevant.  What I meant by not seeing much change in the wave form until the valve is a ways off it's seat is that there wouldn't be any effective flow until the valve is off it's seat a ways.  In other words I would expect to see the change in the wave form on valve open events be a little delayed to actual seat timing  and valve closing events to show up a little earlier than actual seat timing. I of course couldn't really know that with out actually checking that  the old long way with a degree wheel and indicator.
    What that wave form does show is that we can identify valve problems and we can identify  cam to crank timing problems at least as long as there on the order of a tooth or so at the cam drive.
    I really like your anno wave program and I'll have to put that on my list of things to get. I've also been limited to using my pv/500 (same as the pv350 just an earlier version but the exact same transducer and circuitry according to the fluke repair center) Mine has had a few failures along the way and has been to the repair center a couple of times. I've been thinking about upgrading to some different pressure transducers that would offer better resolution in their respective ranges such as the set that ATS offers. I just haven't been able to spend the money quit yet but I will eventually. Do you have any suggestions on transducers?

Title: Re: firstlook
Post by romain on Jun 17th, 2007 at 8:53am
Hi Michael,

I'm curious about that slight bump in the pressure waveform, have you made any comparison with the other cylinders to see if this is uniform throughout the engine or just a signature to that one cylinder only ?

Title: Re: firstlook
Post by mwebb on Jun 17th, 2007 at 11:57am

Romain. wrote on :
Hi Michael,

I'm curious about that slight bump in the pressure waveform, have you made any comparison with the other cylinders to see if this is uniform throughout the engine or just a signature to that one cylinder only ?


i have seen an dimple in another car that did have a bad / leaking exhaust valve ,
   the waveform is below, 1998 bmw 528 , i do not know what significance the dimple has , that cylinder did have a leaking exhaust valve BUT i cant say what if anything in the waveform may indicate that .

                    i will stack up 3 cylinders from that car and see if there is a difference .    

 i did not record any other cylinders from that 944 .    the dimple is not present at idle either , when recording  relative compression waveforms , it seems like i should record idle then 2k rpm values with ckp ,

before i buy another pressure transducer i intend to explore various options , like this .
from Omega.     http://www.omega.com/ppt/pptsc.asp?ref=PX309-5V&Nav=preb03  
        these look very much like the Fluke PV 350 , but i can not say that that is where Fluke gets them from , i have no idea . but it looks like they should work - haveing said that i would NOT PURCHASE one until i found out how well they do with RFI and how well they do rejecting noise induced by vibration and or physical contact .       the microphone effect.
   the Fluke PV 350 has trouble with RFI and the FLS sensor has trouble with the microphone effect.        
 
98_bmw_running_compression_marked_ANNO_wave_001.gif (103 KB | )

Title: Re: firstlook
Post by romain on Jun 17th, 2007 at 3:29pm
With this attachments, I would like to attempt a description of what I think the sudden momentary cylinder pressure drop is caused by,

since the area of the TDC compression is shown, there would have to be a brief pressure relief for the waveform to display the sudden pressure drop,

now since the cam lobes for that cylinder, at this point in time are pointing away from the cam followers, I submit that there is a bad spot / abrasion or irregularity on the base circle of one of the cams, so that the cam follower (Hydraulic) is transmitting it's movement on to the valve, and momentarily releasing pressure, allowing us to witness the resulting drop in the waveform.

in brackets I inserted Hydraulic, as a mechanical valve train would not be able to effect that same condition due to the valve clearance provided .


Sudden_momentary_cylinder_pressure_drop_.jpg (73 KB | )

Title: Re: firstlook
Post by romain on Jun 17th, 2007 at 5:12pm
Hi again,

perhaps an other idea may well be a leaking exhaust valve ( usually due to that valve being stressed greater than the intake, except when carbon buildup is involved )

in the BMW wave, there was a fast pressure drop up to a point, where the lowered pressure made less of an impact on rate of drop,

so looking at the Porsche wave, we may be seeing the beginnings of a leaking valve.

Title: Re: firstlook
Post by mwebb on Jun 18th, 2007 at 10:35am
i can hardly wait until i get a car with a burned exhaust valve to see . :)  

Title: Re: firstlook
Post by rahill on Jun 18th, 2007 at 2:50pm
Michael just out of curiosity could you post the time in degrees  from  tdc to the change or dimple in the wave for both the porsche and the bmw  running compression waves being discussed here. Thanks.

Title: Re: firstlook
Post by mwebb on Jun 18th, 2007 at 10:05pm

Rick Hill wrote on :
Michael just out of curiosity could you post the time in degrees  from  tdc to the change or dimple in the wave for both the porsche and the bmw  running compression waves being discussed here. Thanks.

the 944 has the dimple at 17 degrees after TDC at 2030 rpm .
   i will check the BMW dimple location after i stack up the waveforms
944_Dimple_marked_at_17_degrees_after_TDC.gif (20 KB | )

Title: Re: firstlook
Post by fisher on Jun 18th, 2007 at 10:59pm
So, Ford's Thermactor system was an air pump that sent air to the exhaust stream to assist the catalyst ... but another systemFord used no air pump but, exhaust impulses and some sort of check valve to draw air into the exhaust stream; the exhaust pulses can induce a mild pumping effect at a particular load condition.
Intake manifolds have valves in them to change the direction of flow due to resonance issues.
         Air stretches and compresses both and likewise does exhaust.

Title: Re: firstlook
Post by mwebb on Jun 19th, 2007 at 9:51am

fisher wrote on Jun 18th, 2007 at 10:59pm:
So, Ford's Thermactor system was an air pump that sent air to the exhaust stream to assist the catalyst ... but another systemFord used no air pump but, exhaust impulses and some sort of check valve to draw air into the exhaust stream; the exhaust pulses can induce a mild pumping effect at a particular load condition.
Intake manifolds have valves in them to change the direction of flow due to resonance issues.
         Air stretches and compresses both and likewise does exhaust.



i should have marked it off better sorry ,
 the pressure transducer is in the spark plug thread.
at 17 degrees after TDC right there where the dimple is both of the valves are closed and the piston is heading down . the combustion chamber should be sealed , anything that happens in the exhaust or intake  is isolated by the closed valves  and not connected to the combustion chamber and so should not have any effect at all on the pressure inside of the combustion chamber .
                    assuming the valves have actually  closed .
    the exhaust valve opens at about 155 degrees at which point events in the exhaust will begin to have an effect on the combustion chamber pressure .  

Title: Re: firstlook
Post by fisher on Jun 19th, 2007 at 6:15pm
I was befuddled... So, we are looking at a compression event but no firing event. I had an impression of resonance. I suppose the best way to see about that dimple is to take the motor apart.
Sorry, I thought we were talking about FLS in an exhaust stream.

Title: Re: firstlook
Post by mdog on Jun 19th, 2007 at 7:21pm
I found out something about the Fluke PV350 and trying to use it for determining TDC.  It was 25 degrees LATE.  I used the CKP sensor to give me the true TDC.  Has anyone else checked to make sure their PV350 was really telling the truth?  This is the only car I've ever tried to verify the PV350's accuracy on, but I don't think I would trust it to tell you the true Top Dead Center on an engine.


PV350_reports_late.jpg (481 KB | )

Title: Re: firstlook
Post by rahill on Jun 19th, 2007 at 8:25pm
Yes I'm aware of it.  How many degrees late it is depends on the engine speed the time value is fixed. As long as your not using your transducer to check timing against electrical signals it all relevant though.  Some transducers are faster than others but I think you'll find all are slower than the electrical signal. As long as you are aware of the delay you can compensate for it when checking what the transducer sees against an electrical signal such as your doing there with the crank sensor. If you dig around in the archives on iatn you'll find some vacuum and running compression waves put up by some fella from Russia or maybe it was a link to his site and his transducers were very fast. I remember questioning him about them at the time and the delay was almost nothing as compared to my pv/500.

Title: Re: firstlook
Post by mwebb on Jun 19th, 2007 at 10:20pm
there is a "work around" for the delay thing IF you have ANNOwave , i have taken the waveform out of the Pico 6 capture here and stacked up three of them , they are all "transparent" and can be crunched or expanded or whatever to fit 720 degrees on another Pico 6 capture -
the instructions of how to do that are in the help file , i think

the delay in the FLS sensor is 84 degrees different than the Fluke PV 350 at idle in ONE capture that i have .

also , it looks like it is very important that the PV 350 be dead nutz set on zero BEFORE capturing waveforms     now i dont know if i have a stuck open intake valve on two cylinders or an un zeroed PV 350 , the difference here is 6.6 mv     , cylinder 6 has something stuck open and i thought it was an exhaust valve    , but i dont see that here
ACE Misfire flagged it as well      
1983_MB_380_sl_running_compression__set_zero.gif (62 KB | )

Title: Re: firstlook
Post by mwebb on Jun 19th, 2007 at 10:29pm
ACE Misfire Flags Misfire on Cyl 6    
1983_MB_380_sl_AMD_Misfire_on_cyl_6_.gif (126 KB | )

Title: Re: firstlook
Post by mwebb on Jun 19th, 2007 at 10:42pm

mdog wrote on :
I found out something about the Fluke PV350 and trying to use it for determining TDC.  It was 25 degrees LATE.  I used the CKP sensor to give me the true TDC.  Has anyone else checked to make sure their PV350 was really telling the truth?  This is the only car I've ever tried to verify the PV350's accuracy on, but I don't think I would trust it to tell you the true Top Dead Center on an engine.

AES [and maybe AutoNerdz ?] sells a shielded lead that will lessen the RFI you are capturing with the FLuke PV 350 -      

Title: Re: firstlook
Post by fisher on Jun 20th, 2007 at 10:34am
Like I was telling you, the gas stretttttches; so the electrical is the ONLY way to go to get TDC- the Fluke is no tool to use to determine TDC in the first place. I mean it is not an inaccurate tool so much as it is the wrong tool to use.
  Imagine a tank of gas and the fuel sloshing in it. If you give the gas a shove from one side of the tank, it doesnt register on the other side of the tank till the wave created gets there. Like a wave created by wind a thousand miles away across the ocean takes days to make the crossing and land in Oregon to the south of Tom. If you had a scope and measured the shove where it shoved, it would show you when the shove happened but the Fluke cant record it till it gets to Oregon (and thuslythere  made an impression on the Fluke). These principles and phenomenons are what the OEM is dealing with when he mentions resonance and introduces valves into the intake and high speed runners and idle or mild load runners.
  Gas is more stretchy than liquid. The action of the motor operating actually involves inertia... I mean, the intake is pulling that air in and if you really pulled that piston down hard past BDC and slammed the intake valve shut AFTER BDC; a bit of air kept entering the chamber even though the piston was either stopped or on it's way back up... it was pressurizing even though the piston was attempting to squeeze it back out, by inertia- much more noticeably than liquid which is non-compressible.
Resonance is more like vibration than a simple wave (like on the water example), so I imagine a LOT of what we see with these transducers is due to it.  It would be more hash-like and would appear at differing load conditions, but only under the right ones, like say, idle only or cruise only. I am impressed with how you fellows have been figuring out the FLS. Thanks.

Title: Re: firstlook
Post by fisher on Jun 20th, 2007 at 12:12pm
I spoke late; a good man already had clarified the Fluke thing.

Title: Re: firstlook
Post by mwebb on Jun 20th, 2007 at 2:25pm
i am not looking to find TDC , because it isnt lost  .   i am looking to find exactly where the exhaust valve opens and closes    and where the intake valve opens and closes in relation to TDC or something else .
                  with ANNOwave i can find both , now i can overlay a 720 degree running compression waveform ontop of 720 degrees of another capture and see exactly where things happen so i can figure out what went wrong or didnt go wrong .
                   many thanks to Jorge Menchu at  AES for building the ANNOwave software .

the page got pretty busy , anyway after matching the horizontal time to equal 720 degrees for all objects  i can now move that running compression overlay anywhere and line up the exhaust valve opening EVO of the running compression waveform with the EVO of the FLSe sensor waveform and i can see exactly when everything else happened for that cylinder ,     outstanding .
i could put up 8 overlays at one time or i can simply drag the 1 around to see what i want to see .
                this is exactly what i wanted .
also the option to add in horizontal cursors in either side bar is available but this page is kinda busy already   .

for those that want to find TDC put the pressure sensor on a purge valve , command it open , measure time between command and  transducer response .  build that time as kentucky windage  into your measurements  .
or think about it and come up with your own way . it's  easy , My Mom could do it .
1983_MB_380_sl_AMD_Misfire_ANNO_marked_.gif (94 KB | )

Title: Re: firstlook
Post by mwebb on Jun 21st, 2007 at 9:53pm
same mercedes 1983 380sl  3 cylinders

another feature of ANNOwave - here is a 1983 Mercedes 380sl
cylinder 2 6 7 running compression . the running
compression waveforms are transparent and i can load them
over 2ndary spark with FLSe captures to see what happens
when which valve is open .

and unknown to me , another option . ANNOwave ANIgif
running compression
Mercedes_1983_relative_compression_ANIgif.gif (66 KB | )

Title: Re: firstlook
Post by mdog on Jun 22nd, 2007 at 5:25am
For Mike Webb,

Your getting good with that Anno Wave.  I'll have to try some of those features out this weekend :D

Title: Re: firstlook
Post by mwebb on Jun 25th, 2007 at 8:12pm
http://www.quantex.ru/portal/methodics/gas.aspx

this is a russian web site , i dont speak russian , but it looks like they are quite a bit ahead of the Americans on the use of pressure transducers ?  how on earth did that happen ?
bablefish will translate parts of this .  

Title: Re: firstlook
Post by Tom Roberts on Jun 26th, 2007 at 7:14am
Lest we forget....The Russians were first in space and first to land on another planet.   :o
venera13_sfc_02.jpg (46 KB | )

Title: Re: firstlook
Post by mwebb on Jun 27th, 2007 at 10:09pm
color=#ff0000]Chernobyl sunrise - and how many "hot" spots dot the ocean floor ? from soviet nuclear powered submarines with system failures , crews forever preserved by the radiation that permeates the areas they are now resting in ,  half life of the melted reactors measured in millions of years .
 [/color]

but they do have us beat on pressure transducer use , i think , still cant translate easily  

Title: Re: firstlook
Post by mwebb on Jun 28th, 2007 at 7:31pm
with the ANNOwave software using the ANI gif option , a previous image -  much smaller fingerprint than the russian website flash presentation -  ok theirs is better , but mine is in english and it was made in America .    
96_accord_relative_compression_stack_ANNO_ANI.gif (88 KB | )

Title: Re: firstlook
Post by mwebb on Jul 3rd, 2007 at 9:45pm
maybe i have figured out how to slow down the ani gif , here is another way to mark off 720 degrees , this time i use an overlay of the running compression waveform , then use vertical cursors to show exhaust valve open and close , this shows misfire on cylinder 2 .  there is restricted flow as marked by ripple in the FLSe waveform from carbon or ? the exhaust valve is not leaking because there are no Higher pressure exhaust valve opening events as a leaking exhaust valve would create .  
1987_944_FLSE_2ndary_misfire_ani_.gif (89 KB | )

Title: Re: firstlook
Post by mwebb on Jul 3rd, 2007 at 10:08pm
and again - maybe slower ....
1987_944_FLSE_2ndary_misfire_ani__001.gif (88 KB | )

Title: Re: firstlook
Post by mwebb on Jul 3rd, 2007 at 10:12pm
now it will not have the ani gif , just gif , i have to learn how to control these things

after calibrating running compression overlay waveform to known 720 degrees in the waveform ...

anyway if nothing else , you can see very clearly how to determine where TDC is based in the time of the FLS e pressure transducer ,  just set the exhaust valve opening event to match a previously recorded running compression waveform from the same engine and where TDC is is where it is - of course the spark waveform will be before it -  the spark waveform should be before it the number of degrees shown in scan data -    but it wont be because of the delay in the pressure transducer so ....

you could position the running compression waveform based on spark advance value in scan data to see when the events are actualy happening in relation to spark or CKP or ....
using the vertical cursors measuring in degrees [ calibrated to known 720 degrees in the waveform ]  to set the exact position    
1987_944_FLSE_2ndary_misfire.gif (92 KB | )

Title: Re: firstlook
Post by mwebb on Jul 15th, 2007 at 9:45pm

this is out of the though sequence here ... but it relates to the FLSe transducer delay , or the MAF sensor delay or both .
this shows misfire in cylinder 3 as per the FLSe waveform , dead injector , no biggie .
  but the misfire is also shown by a hiccup in the MAF sensor waveform for cylinder 2 intake pulse .
 
  to me , a biggie that i will remember and watch for .

1993_nissan_240sx_Misfire_on_3_FLSe_MAF_.gif (88 KB | )

Title: Re: firstlook
Post by rahill on Jul 19th, 2007 at 4:42pm
Here are a couple of fls captures on an 04 f 150 5.4 with a vct system. This engine is very sick and surprisingly only one cylinder has no compression according to a relative compression test and it's not where you might think it would be looking at the fls wave forms.  One of these captures is in the intake at about 510 rpm and the other is in the exhaust at about 1760 rpm. See if they will tell you anything about the condition of this motor or is there any useful info there at all.  I will add these in psdata so you can manipulate them and they were done on version 6.06 if it matters.
    Here is one from the exhaust.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_F_150__FLS_EXHAUST.psdata (334 KB | )

Title: Re: firstlook
Post by rahill on Jul 19th, 2007 at 4:43pm
Here is the one from the intake running at about 510 rpm.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=O4_F_150_FLS_INTAKE.psdata (193 KB | )

Title: Re: firstlook
Post by mwebb on Jul 19th, 2007 at 9:20pm

Rick Hill wrote on :
Here are a couple of fls captures on an 04 f 150 5.4 with a vct system. This engine is very sick and surprisingly only one cylinder has no compression according to a relative compression test and it's not where you might think it would be looking at the fls wave forms.  One of these captures is in the intake at about 510 rpm and the other is in the exhaust at about 1760 rpm. See if they will tell you anything about the condition of this motor or is there any useful info there at all.  I will add these in psdata so you can manipulate them and they were done on version 6.06 if it matters.
    Here is one from the exhaust.

---------------------------------------------------------------
for the record , this doesnt work well when there is a wave running through the waveforms ,  here i ignore the wave , but that is a bad idea    but that is the only sample presented .  
engine rpm is not stable , exhaust events are not evenly spaced and should occur every 90 degrees  .
               720 degrees  divided by 8 cylinders .  1 exhaust valve opens every 90 degrees .  

              and i need a much huger sample to pluck a stable 720 degrees  from.... but  working with what i have here  i get the following     ,  
    i dont see a misfire signature here and i dont see the effects  of the o2 puff following a misfire .... but i can line up the "combustion power " event   connected to the exhaust when there should be a lesser pressure dip than there really is ...
    so based on what is presented i see leaking exhaust valve on the fourth cylinder in the fireing order relative to the spark shown .

but that is ignoring the effects of that wave .... i need a bigger sample---    100ms psdata stable at hot idle with trans in gear brake on if possible .  
Rahill_ford_5_4_1760_rpm_FLSe_ani.gif (78 KB | )

Title: Re: firstlook
Post by mwebb on Jul 19th, 2007 at 9:25pm
for the record , this doesnt work well when there is a wave running through the waveforms ,  here i ignore the wave , but that is a bad idea    but that is the only sample presented .  
  engine rpm is not stable , exhaust events are not evenly spaced and should occur every 90 degrees  .

             and i need a much huger sample to pluck a stable 720 degrees  from.... but  working with what i have here  i get the following     ,  
    i dont see a misfire signature here and i dont see the effects  of the o2 puff following a misfire .... but i can line up the "combustion power " event   connected to the exhaust when there should be a lesser pressure dip than there really is ...  
    so based on what is presented i see leaking exhaust valve on the fourth cylinder in the fireing order relative to the spark shown .  

but that is ignoring the effects of that wave .... i need a bigger sample---    100ms psdata stable at hot idle with trans in gear brake on if possible .

for those who prefer a stable gif  
Rahill_ford_5_4_1760_rpm_FLSe_.gif (66 KB | )

Title: Re: firstlook
Post by rahill on Jul 20th, 2007 at 10:16am
Hi Michael
     I agree those captures are hard to make much of. You may well be right about that exhaust valve leak at the fourth  in the order . I'll check that before it's gets torn down. The firing order here is 13726548.  I can't really slow the engine down and get a more stable capture over a longer period of time. If I let it idle  that wave as you call it running through the wave form will get like the intake capture and I'll have to raise the voltage scale on the scope to the point that you'll no longer see any individual pulses or it will run right off the screen.  It becomes extremely unstable at slower speeds. Did you look at the intake capture and notice how the wave running through the wave form is like the inverse of what you see in the exhaust?  I'm pretty much thinking about what I might see in these wave forms when the valve timing is way out of sync with the piston position.  The only thing that makes me rethink that  is the ignition and injector timing is right according to the crank sensor and the fact that I show eight cylinders in a relative compression test. I think if one cam was 360 out of time I would only see four  cylinders in a relative compression test. The cams are synced together so if one is out of time both are out of time. There was the possibility of one being 360 off but the eight pulses in the compression test kind of ruled that out I think. I can pretty positively say at least one intake valve is wide open or close to it when the piston comes to tdc compression. From the fls wave forms  it looks to be the 4th in the firing order but from the relative compression capture it would logically be the 7th in the firing order.
    Thanks for taking a look at that and giving me your opinion on what you see in there. I know it takes a bit of your time to look through those captures and annotate them as you've done. I know I spend a bit of time looking through them a number of times after I've looked through them the first time for anything that just obviously stands out. I notice it looks like you figure there is a pretty good delay in the fls reporting when compared to an electrical signal. I found about a 3 ms delay in my pv 500 but I've never checked the fls for delay. I have gone under the assumption that it was at least quite a bit faster than my pv 500  and haven't figured on the delay much when looking at these wave forms.  I believe it's a piezo device rather than a pressure transducer and assumed it to be faster to report. Do you figure the delay to be about the same as your pressure transducer? I guess I should check it and find out what the delay actually is so I can figure that in there as well.
 Here is a relative compression capture  to give you a little more info about why those fls waves may look like they do with the blue being starter current and the red being #1 primary.
04_f_150_relative_compression.gif (20 KB | )

Title: Re: firstlook
Post by mwebb on Jul 20th, 2007 at 4:17pm
before you open it up ....
please get a running compression waveform from each bank and 1 from the cylinder with no compression .  psdata    50ms    try to get them all at the same rpm .  
i can annotate them pretty quickly , and i can stack them up to see cam timing issues .

also , FLS in the oil stick , to see if there is a vacuum leak into the crankcase and to see if there are bad piston rings somewhere .
      FLS will pick up vibrations from engine contact so wrap it in rags or whatever to isolate it as best you can .  i hang the FLS from the hood latch so it doesnt touch anything .  
include MAF signal set on AC coupling to partially  fill the screen
sync on something , #1 primary is ok .
psdata 100ms or 50ms


i learn by doing this stuff .  

Title: Re: firstlook
Post by Wilf on Jul 20th, 2007 at 4:52pm
A lot of the time (always) mechanical integrity is easier to see with the engine cranking and not running.
I use two FLS 100 testers and do intake and exhaust at the same time with a sync.
That way you don't have to deal with any turbulance caused by the misfire.
That is my 2 cents
Take it for what it is worth
Here is an example of a toyota

Wilf
panoramic_crank.gif (213 KB | )

Title: Re: firstlook
Post by rahill on Jul 20th, 2007 at 5:56pm
Michael
The truck is still laying around here so I'll see about getting those running compression waves.  Maybe I can do that in the morning. I just got a 16x1.5 compression test adapter for it yesterday afternoon.
   This thing will not run at a steady rpm at idle but I'll see what I can do. It only has 6-8 inhg of vacume and that fluctuates about 4 inhg up and down when it tries to idle. If this  wasn't computer controlled it wouldn't even run with out making some major adjustments.

Wilf
   Thanks for that suggestion on using the fls for a cranking test you make a very good point. I don't have two fls' but I'll take a look see with the one I have..  

Title: Re: firstlook
Post by mwebb on Jul 21st, 2007 at 7:30am
yes of course , Wilf's suggestions should give up the problem and it will eliminate the "wave" .
you may want to  attempt to AC couple the MAF sensor signal with FLSe   for the intake  pulses waveform.  and sync it to something .

still i would like the running compression waveform s , and idle with FLS in the oil stick with maf ac coupled , just for reference ... please o please .

i have to leave a note on the laptop remember the cranking tests .... i am not getting any younger  

Title: Re: firstlook
Post by mwebb on Jul 22nd, 2007 at 11:19am
here is the Intake FLSi  waveform overlayed on top of the FLSe waveform .  if these patterns are consistently the same ????  
i can overlay the cranking waveforms to verify the answer to the question .

i would like running compression waveforms for cyl 7 2 6 and one other ... for reference please o please .
Rahill_ford_5_4__FLSe_FLSi__undefined_.gif (81 KB | )

Title: Re: firstlook
Post by rahill on Jul 22nd, 2007 at 12:55pm
Hi Michael
      I will get those wave forms but I got side tracked yesterday with Dogs and didn't get them done. Friend of mine was running a bear south of here for the game and fish folks with my tracking collars on his dogs. I have my name ph number and address on my tracking collars so all day long I kept getting calls about lost dogs showing up in folks yards. Most folks don't understand those collars are radio transmitters so they don't know what to think when you tell them that the dogs owner will be along shortly. I ended up taking a trip south to help round up dogs. In the old days these dogs had good homing instincts because they always just ran loose on a fellas property and went where they wanted but these days they spend all their time in a kennel so on a hunt after a couple days on track they get hungry and go to the first sign of civilization rather than home. The homing instinct has been kind of bred out of them so to speak.

    I see you and I are roughly on the same page with those wave forms. I came up with the peak in that intake wave being at about 442 degrees after #1 firing event but I also came up with 442 degrees after the firing event in the exhaust wave as being about 42ms after the firing event  you show that point as being a little earlier than 442 degrees. I still tend to think there is a valve timing problem here as well. I guess we'll know more about that as soon as I get those captures done.
     Time wise what do you figure the delay to be with the fls?  Thats something I'm still unsure of.

Title: Re: firstlook
Post by mwebb on Jul 22nd, 2007 at 6:33pm

Rick Hill wrote on :
Hi Michael
      I will get those wave forms but I got side tracked yesterday with Dogs and didn't get them done. Friend of mine was running a bear south of here for the game and fish folks with my tracking collars on his dogs. I have my name ph number and address on my tracking collars so all day long I kept getting calls about lost dogs showing up in folks yards. Most folks don't understand those collars are radio transmitters so they don't know what to think when you tell them that the dogs owner will be along shortly. I ended up taking a trip south to help round up dogs. In the old days these dogs had good homing instincts because they always just ran loose on a fellas property and went where they wanted but these days they spend all their time in a kennel so on a hunt after a couple days on track they get hungry and go to the first sign of civilization rather than home. The homing instinct has been kind of bred out of them so to speak.

    I see you and I are roughly on the same page with those wave forms. I came up with the peak in that intake wave being at about 442 degrees after #1 firing event but I also came up with 442 degrees after the firing event in the exhaust wave as being about 42ms after the firing event  you show that point as being a little earlier than 442 degrees. I still tend to think there is a valve timing problem here as well. I guess we'll know more about that as soon as I get those captures done.
     Time wise what do you figure the delay to be with the fls?  Thats something I'm still unsure of.

there is no rush , i just would like the waveform before it gets dissassembled if possible  

if you get scan data timing value , and a running compression waveform , i can position the exhaust waveform where it should be relative to the spark waveform , same with the intake .  
you can see the values in degrees as valves open and close with TDCs and BDCs .  you can compare those measured values to Ford specification and see if there is valve timing problem s . [and CMP CKP ?]
     
            and as Wilf suggested , cranking FLSe with MAF signal on AC coupling synced to something.

i would concentrate on that spike in the intake if i were doing this , then the 2 misfires .

 the dogs have priority.

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 3:44pm
Michael here are the running compression waves for the cylinders you asked about.There are no revelations here for me as I already knew there wasn't anything wrong with this a new set of heads wouldn't cure.  With a leak tester on #4 the intake is always open but I can hear that the cam is moving the valve as I roll it through. I think maybe that intake is bent or a seat fell out. Do they do that?
 Anyway I'll start with #4 and I'll put up the psdata file so you can manipulate them.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f150_running_compression_4.psdata (42 KB | )

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 3:47pm
here is #7. These are all synced to #1 primary.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f150_running_compression_7.psdata (33 KB | )

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 3:48pm
here is #2.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f150_running_compression_2.psdata (30 KB | )

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 3:50pm
here is #6.  
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f150_running_compression_6.psdata (31 KB | )

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 3:55pm
Running with the fls at the dipstick and the maf ac coupled didn't come out so well. I couldn't seem to get rid of the noise and the same with the fls and the cranking waveforms I think mostly over using such a low voltage range to get much of a wave form. Here is running with the fls at the dip stick and the maf ac coupled.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f150___maf_ac_coupled_fls_at_dipstick_001.psdata (22 KB | )

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 3:57pm
The cranking with the fls did not get rid of the wave through the waveform here is fls at the intake cranking along with the maf ac coupled
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f_150__fls_intake_cranking.psdata (22 KB | )

Title: Re: firstlook
Post by rahill on Jul 24th, 2007 at 4:00pm
Last is cranking with the fls in the exhaust. This did change some from the running exhaust capture but there is a lot of noise on the signal. I tried wrapping the fls in rags and seting it on a stand not connected to the truck but it didn't seem to help much.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f_150_fls_exhaust_cranking.psdata (42 KB | )

Title: Re: firstlook
Post by mwebb on Jul 24th, 2007 at 9:04pm
 i cant really fit #4 into a place i am happy with on #7 .  
i would have liked larger samples with a few 720 degree cycles , like 100ms in psdata not just 1 screen with 1 event so i can take what i need to get a match ,
both have been sized to 720 degrees and #4 is overlayed on top of #7    valve opening and closing are marked off for #7    i dont know what factory specification is .  vertical on #4 is not scaled to match #7 but they are both 720 degrees as per sync provided

i would like a larger / longer  sample of #4 running compression ... please o please  
Rahill_ford_5_4_RC_7_with_4_overlayed_ani.gif (51 KB | )

Title: Re: firstlook
Post by mwebb on Jul 24th, 2007 at 9:39pm
here is with running compression of cylinder 7 with running compression from cylinder 2 with running compression from cylinder 4
the begin and end in degrees for #4 are not the same as the other 2 , all three waveforms cover 720 degrees   2 is bank 1,  7 bank 2   there does seem to be a very slight cam timing difference between bank 1 and bank 2   ? ???  
Rahill_ford_5_4_RC_7_and_2_with_4_overlayed_ani.gif (61 KB | )

Title: Re: firstlook
Post by rahill on Jul 25th, 2007 at 10:59am
Michael when you opened the #4 running compression test did you click on 100%.  The truck is now being torn down so I can't get another capture. There is as much time on #4 as the others. I had at first thought there was a possibility of one cam being 360* out of time but  it looks as if that is not the case so I guess the pictures in alldata in the timing chain replacement section are misleading as to where the teeth for the cmp sensors fall. In there it looks as if the 3 teeth and the 2 teeth should be 360* from each other but that can't be the case looking at the running compression wave forms. The valve timing events also look to fall about where they should as well so I'm going to say the cams must at least be very close to correctly timed. Given that this cnk sensor cam sensor relationship must be about correct and this looks different than any fords I've looked at in the past. Normally I would see the first of the three teeth and the first of the two teeth cross zero voltage at 20*-25* atc and in this case it's the second of three teeth crossing zero at 10*atc and that tooth is missing in the two tooth pattern. I'm going to say the cmp to ckp sensor relation ship is possibly a little early but otherwise correct and does fall inside the internal pip window of 10*btc and 35* atc. Until I see different I have to say the cmp,ckp relationship is correct. Below is what it looks like with the actuators at 0 duty cycle or fully advanced as the duty cycle on the actuators increases the cams will retard from this point. The vct has a range af about 60*

 You are pretty good with that anno waveform program and do a nice job of putting those waveforms into perspective. Thanks for taking a look at these it helps confirm what I'm thinking about this thing.
https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=04_f_150_ckpcmpign_prim.psdata (212 KB | )

Title: Re: firstlook
Post by mwebb on Jul 30th, 2007 at 6:58pm
this thread is getting to be like a run on sentence , but the subject is still the same ? i guess , so ....

new "Tip" for the FLSe sensor for when you use it in the exhaust -    From    ATS , does it work , yes , does it do what they say it will do ? i dunno , i dont know what they say it does .  

this is what it does do ,
i have captured FLSe synced to #1 primary on a 6 cylinder BMW M52 engine , these  are hash makers , there is almost always a lot of mess in the exhaust pulse train on these .
  i made a different "tip" to use on everything , it increases amplitude and it works for that , it does not really do anything for the hash .    This "Tip" from ATS does clean up the hash but , you loose amplitude .
both captured with the same FLS sensor from the same car at hot idle in reverse with brake on , no DTC .
 below i have overlayed the FLSe ATS waveform   just below the waveform captured with my "tip"
it is easier to identify a weak exhaust pulse which usually equals a low flowing injector , there are no "long line" misfires     i have overlayed cursors to mark off where the ATS waveform shows the peak of the weak pulse and put the cursors at the same place , 84% on the waveform with my "tip "
                                 it is much easier to see it with the ATS "Tip" .  
                                             
using AES ANNOwave software i have matched 720 degrees to 720 degrees and i matched the amplitude exactly so that amplitude would not be  a part of this comparison .

the car idles smoothly hot in gear, no perceived misfire or anything .
     
ATS_FLS_tip_compared_10w_6v_ani.gif (143 KB | )

Title: Re: firstlook
Post by mwebb on Jul 30th, 2007 at 7:32pm

for those who dont like the ani gif , here is just gif

new "Tip" for the FLSe sensor for when you use it in the exhaust -    From    ATS , does it work , yes , does it do what they say it will do ? i dunno , i dont know what they say it does .  

this is what it does do ,
i have captured FLSe synced to #1 primary on a 6 cylinder BMW M52 engine , these  are hash makers , there is almost always a lot of mess in the exhaust pulse train on these .
  i made a different "tip" to use on everything , it increases amplitude and it works for that , it does not really do anything for the hash .    This "Tip" from ATS does clean up the hash but , you loose amplitude .
both captured with the same FLS sensor from the same car at hot idle in reverse with brake on , no DTC .
 below i have overlayed the FLSe ATS waveform   just below the waveform captured with my "tip"
it is easier to identify a weak exhaust pulse which usually equals a low flowing injector , there are no "long line" misfires     i have overlayed cursors to mark off where the ATS waveform shows the peak of the weak pulse and put the cursors at the same place , 84% on the waveform with my "tip "
                                 it is much easier to see it with the ATS "Tip" .  
                                             
using AES ANNOwave software i have matched 720 degrees to 720 degrees and i matched the amplitude exactly so that amplitude would not be  a part of this comparison .

the car idles smoothly hot in gear, no perceived misfire or anything .
ATS_FLS_tip_compared_10w_6v.gif (118 KB | )

Title: Re: firstlook
Post by Wilf on Jul 31st, 2007 at 5:00am
Mike

Could the one slightly shorter exh pulse not be caused by something other than an injector?
Do you have an acompaning injector capture to show us that there is a poorly flowing inj in this vehicle?

Wilf

Title: Re: firstlook
Post by mwebb on Jul 31st, 2007 at 11:09am

Wilf wrote on Jul 31st, 2007 at 5:00am:
Mike

Could the one slightly shorter exh pulse not be caused by something other than an injector?
Do you have an accompanied injector capture to show us that there is a poorly flowing inj in this vehicle?

Wilf

as one example ;
in the GTD forum look in the thread about the 4.7 jeep , you will see a image of low er FLS fpr pulses in the fuel rail which line up with weak puffs in the exhaust pulse train .
in my limited experience , when ever i follow up ,a weak exhaust pulse WITHOUT a long line misfire = low flowing injector .
                         but since you have been doing this longer than me ..... feel free to show me what i am doing incorrectly .  :)  

but on this BMW i have not proved what the waveform shows - i was   comparing the waveforms from the 2 tips more than i was looking to fix a car .  

Title: Re: firstlook
Post by rahill on Jul 31st, 2007 at 12:06pm
Michael what is the difference between the two tips?  Smaller opening, larger opening, screen or restriction in the coupling?
   I looked at the wave forms you annotated for the 4.7 and I would agree with your analysis of the waveforms but I kind of wondered about whether the fuel wave pulse problem were really for   #1 and #6 injectors. That would put injection  somewhere around 150 degrees before the intake valve opened which seemed kind of early. I've never looked at the injectors on one of these so I really don't know but  like that ford I was looking at up above the injectors were triggering at about 70 degrees before tdc overlap or intake valve opening. Made me wonder if what we were seeing in the exhaust waveform on that 4.7 was really caused by an injector although it would make sense that it was. I would like to have seen an injector capture on #1 and #6 to go along with the fls exhaust capture.

Title: Re: firstlook
Post by Wilf on Jul 31st, 2007 at 2:37pm
Mike

I doubt that I have used the FLS more than you
I wanted to see a inj capture to try and gain knowledge from someone that uses the toolconstantly
I neversaid anyone was doing anything incorrectly
Rather than let this forum turn into a copy of others I can simply stay away

Wilf

Title: Re: firstlook
Post by Tom Roberts on Jul 31st, 2007 at 7:06pm

Quote:
Rather than let this forum turn into a copy of others I can simply stay away


Don't you dare Wilf   ;)  I think you know that FLS better than anyone.  Certainly better than me  :-?

It's easy to jump to conclusions with that tool as the waves leave a lot to interpretation.  You question everything.  This is good.  With a tool like that you need to substantiate things to draw valid conclusions.  It's easy to assume things that later prove to be less than completely accurate.

Title: Re: firstlook
Post by mwebb on Jul 31st, 2007 at 8:48pm

Wilf wrote on :
Mike

I doubt that I have used the FLS more than you
I wanted to see a inj capture to try and gain knowledge from someone that uses the toolconstantly
I neversaid anyone was doing anything incorrectly
Rather than let this forum turn into a copy of others I can simply stay away

Wilf

  nobody ever critisizes my  posts  ... it is good that some one has :) , i wish more people would actually so that i can make changes as needed to improve my swags and abilities  ,  no one should stay away  least of all you Wilf you were the one that showed me about  valve opening and closing events in the first place   ,,

i meant it when i typed if i am doing something incorrectly , i would like to know about it.        

   i still have the car , i got a waveform with the Fluke PV350 AC coupled  on the injector rail hoping to see injector flow per cylinder ... but the waveform does not sync and is not usable   .
everything looks different ... same BMW .   more time on thursday .
             now it does have "long Line" Misfire on #1  

here is how i find the delay , that is a honda running compression waveform overlayed , close but not exact .      



the new ATS "  tip" looks like a tube within a tube , a clamp to hold it to the tail pipe  ....
i will post a photo .  
1996_BMW_328is_Long_Line_Misfire_on_1.gif (91 KB | )

Title: Re: firstlook
Post by mwebb on Jul 31st, 2007 at 9:00pm
in ani gif
1996_BMW_328is_Long_Line_Misfire_on_1_ani.gif (107 KB | )

Title: Re: firstlook
Post by utooflyer on Aug 1st, 2007 at 3:32am
great site!
i only come on this site to learn.
i thought at the start i knew it all.. 27 years fixing cars
most cars are fixed with common sense air leaks or misfire due to spark arcings out or the scan tool points you were to follow? alldata or bosch esi-tronic its easy??? or dealer back up ..lost that long time ago...knowledge is power!!
i came on this site i reaserched a scope as you do,the old foot n the mouth is a curve i will never be caught with my first fk up again..or second mitsi gdi lol i learn the hard way ..but its cool
found a guy roberts scary he knows shitloads!!!
then john t and wilf and jarviss and rich b and mr fisher and now we got mick and ronnie!! and mike webb and old school ekul(helpful guy) nick from uk
all you guys scare me but i wouldnt change` it for the world.
.. wilf i feeel you dont give enough away to totties like me i need to learn i want your skills keep posting and keep me learning I want to learn what mike webb is` showing and wilf you intimidate the hell out of me but you are  my instructor! help me regards
john  ..no smilys this time.......

Title: Re: firstlook
Post by John Thompson on Aug 1st, 2007 at 6:31am
Hi Mike,

The difference in 02 content (contained between individual cylinder exhaust strokes) drives differential pressures between the exhaust strokes of good combusting and misfiring cylinders.  The unconsumed O2 (and sometimes HC) from a misfire (or partial misfire) causes a difference in mass between the exhaust strokes (homogeneous gasses and non-homogeneous gasses). Non-homogeneous masses create an obvious pressure differential in the signal created by the FLS.
I think you are equating the “long line” pressure transitions (in the signal created by the FLS) between exhaust pulses as the signature of a misfire and that is correct. Any pressure transition between exhaust pulses is an indication of a differing combustion event between cylinders.  It’s just that the “longer the line”, (greater the pressure transition) the greater the misfire if that helps. Long line misfires are “dead holes” that you and your customers will definitely “feel”. Shorter lines (lesser pressure transitions between exhaust strokes) are partial misfires or combustion inefficiencies that you may “feel” as a quiver or not “feel” at all.

Since the FLS is a Piezo device, I look at the FLS waveforms as the “sound” of each cylinders exhaust stroke. Of course each cylinder’s (entire or total) sound will occur at a predictable point of a 720 degree cycle, differences between individual exhaust stroke “sounds” are easily identified. With the resonance difference that “different design” exhaust systems create through different bends and different muffler baffling however, I’m not sure that that you can dissect and analyze the mini-content of each exhaust strokes “sound” in the same way between “different” manufacturers and engines. What “sounds” like a burnt valve on a Ford may “sound” like a low flowing injector on a Chevy? I dunno, but I think that at least valve "sounds" may be easier done on the intake side of things with the FLS. That’s my take for WIW, but I think that between you and Wilf working these signals so much we'll probably all know sooner or later  ;)



mwebb wrote on Jul 31st, 2007 at 8:48pm:
the new ATS "  tip" looks like a tube within a tube , a clamp to hold it to the tail pipe  ....
i will post a photo .


A tube within a tube is a venturi (http://en.wikipedia.org/wiki/Venturi_effect) which should smooth the signal somewhat and maybe make the overall pressure differentials easier to pick out but I’m not sure that’s a good idea for what you and Wilf are doing since you will lose some waveform “sound” definition and change the picture.

Title: Re: firstlook
Post by Sleuth on Aug 1st, 2007 at 2:48pm
Not picking straws here guys or trying to be negative, but John finally mentioned something i can relate to, when is the missfire a missfire? All combustion engines have missfire`s to some extent, some engines more so than others,  I haven`t used John`s software,  must have some filters to filter out certain "built in missfire" or abnormalities in the firing /combustion process? Are we not approaching design and function with the current crop of auto diag tools? Does the OEM taylor the o2 sensors surface area-construction for this? Perhaps I am not being "picky" enough.

Title: Re: firstlook
Post by mwebb on Aug 3rd, 2007 at 9:05pm

wrote on :
Not picking straws here guys or trying to be negative, but John finally mentioned something i can relate to, when is the missfire a missfire? All combustion engines have missfire`s to some extent, some engines more so than others,  I haven`t used John`s software,  must have some filters to filter out certain "built in missfire" or abnormalities in the firing /combustion process? Are we not approaching design and function with the current crop of auto diag tools? Does the OEM taylor the o2 sensors surface area-construction for this? Perhaps I am not being "picky" enough.




did the factory techs of the 50s wonder how they would ever improve the technology available at the time ?  

i  

Title: Re: firstlook
Post by utooflyer on Aug 4th, 2007 at 8:34pm
your the only person i would spend my my days listnent too you have a passion!!
have a good day mate!!!!
was` that merc      white or black???

Title: Re: firstlook
Post by mwebb on Aug 12th, 2007 at 9:01pm

Wilf wrote on :
Mike

Could the one slightly shorter exh pulse not be caused by something other than an injector?
Do you have an acompaning injector capture to show us that there is a poorly flowing inj in this vehicle?

Wilf

  i am looking for something else to cause " weak puff " signature , so far unsuccessfully , but i will keep trying -

a long line misfire should cause a "weak puff" signature in the FLSe pulses ... but it can not because when the engine slows down from the misfire , the "Long Line" signature that is displayed is right on top of where the "weak puff " would be .          

sometimes - the intake pulses will give up a misfiring cylinder by dropping vacuum just a little when the engine slows down from misfire or partial misfire  and sometimes intake pulses do not give up a thing ?

weak puff
i was trying to see if i could get a weak spark signature from this 2002 lancer 2.0 at hot idle , i was holding the spark plug wire for #3 out of the end of the DIS coil about a 1/2 inch ... i was trying to get weak spark but not long line misfire ,  i never did get an FLSe signature for weak spark , but i did show that on this car    at hot idle  spark or weak spark does not cause a "weak puff " signature .   and on this car , the intake pulses do dip to show misfire and or partial misfire .

but   there is also a regular wave riding the intake pulses. the wave is longer than 4 cylinders and shorter than 8 ....does'nt sync ,  low peaks on that wave should not be confused with a misfire .
one day when i have nothing to do , i intend to track down that wave as many but not all engines have it , i have my suspicions .
      [/color]
2002_lancer_2_0__LL_misfire_No_weak_puff__delay_001.gif (84 KB | )

Title: Re: firstlook
Post by fisher on Aug 13th, 2007 at 3:02am
I wonder if that wave is harmonic...or alias.

Title: Re: firstlook
Post by fisher on Aug 14th, 2007 at 11:41am
Maybe I am confused, you said there was a wave that was between 4 and 8 cylinders in length. I took it to mean that it was not happening every rev or every other rev, relative to the spark firing event or TDC on CKP, say. If it did not sync to th electrical impulses on the car then it would be some kind of noise or whatever.

Title: Re: firstlook
Post by mwebb on Aug 14th, 2007 at 3:26pm

fisher wrote on Aug 14th, 2007 at 11:41am:
Maybe I am confused, you said there was a wave that was between 4 and 8 cylinders in length. I took it to mean that it was not happening every rev or every other rev, relative to the spark firing event or TDC on CKP, say. If it did not sync to th electrical impulses on the car then it would be some kind of noise or whatever.


  ....or could it be that overall engine vacuum fluctuates slightly with mixture change related to what the o2 sensor is doing ... or IAC flutter has an effect , or
  choice C something else .. most likely choice C.      

have to see if the wave in the intake vacuum does sync to something , so if you have the FLSi connected anyway ... and you have a few extra minutes ....  

Title: Re: firstlook
Post by mwebb on Aug 16th, 2007 at 10:16pm
we can make it get confusing .or we can make it very confusing ..

but we can also try and sift through the confusion and find  what signature = which condition    and then record it / remember it for the next time .    
even when i dont find the answer the first time , i can learn by failing .

here is something ... a misfire or ? a ? intake pulses do not show anything .  
2000_passat_ATQ_2_8_misfire_on_3_or_6_ani_001.gif (133 KB | )

Title: Re: firstlook
Post by mwebb on Aug 17th, 2007 at 9:01pm

                              or it can be very simple and un-confusing .      

2000 VW / AUDI ATQ V6 2.8 DOHC .

like this , a running compression waveform captured while an Omega pressure transducer [set on AC coupling ] is connected to the intake vacuum ... higher vacuum is up on the waveform . this cylinder's fuel and spark are disconnected .
you can clearly see the effect or affect ? that the induced misfire has on the intake vacuum waveform , and you can see that the intake vacuum aligns with the valve events in the running compression waveform .
a Fluke PV 350 transducer grounded to battery negative was used to capture the running compression.
the two transducers do not have the same response time ... the waveforms are very slightly staggered , but close enough to see ... that the misfire is reflected by dip in the intake vacuum equal to about 25% of the amplitude of the change in vacuum in the waveform itself . a tiny but very measurable amount .

so now we know , misfires are reflected in dips in intake vacuum that line up with the intake valve opening events of the misfiring cylinder . at least on this ATQ V6 engine .

2000_passat_ATQ_RC_Omega_Intake__4_Misfire_.gif (75 KB | )

Title: Re: firstlook
Post by mwebb on Aug 17th, 2007 at 9:04pm
 
     
ani gif , same as above , but different .
, but you learn a lot while trying .

2000 VW / AUDI ATQ V6 2.8 DOHC .

like this , a running compression waveform captured while an Omega pressure transducer [set on AC coupling ] is connected to the intake vacuum ... higher vacuum is up on the waveform . this cylinder's fuel and spark are disconnected .
you can clearly see the effect or affect ? that the induced misfire has on the intake vacuum waveform , and you can see that the intake vacuum aligns with the valve events in the running compression waveform .
a Fluke PV 350 transducer grounded to battery negative was used to capture the running compression.
the two transducers do not have the same response time ... the waveforms are very slightly staggered , but close enough to see ... that the misfire is reflected by dip in the intake vacuum equal to about 25% of the amplitude of the change in vacuum in the waveform itself . a tiny but very measurable amount .

so now we know , misfires are reflected in dips in intake vacuum that line up with the intake valve opening events of the misfiring cylinder . at least on this ATQ V6 engine .
 
2000_passat_ATQ_RC_Omega_Intake__4_Misfire_ani.gif (89 KB | )

Title: Re: firstlook
Post by jarvissamuel on Aug 18th, 2007 at 6:55am
Hi Michael

I have a question.  What benefit does hooking the pv350 to bat neg?  Everytime I have used it I have hooked directly to the scope leads.

I think mine is broke I was trying to check for a timing issue on an 98 explorer 4.0 ohv and it would not show the vacuum portion.  It has in the past and this was with a new 9v batt.

Anyone know where to get a pv350 checked/fixed or is just cheaper to replace it?

Here is an image of the pv350 capture
98explorer4Lohv_comp_1.gif (47 KB | )

Title: Re: firstlook
Post by fisher on Aug 18th, 2007 at 11:52am
Hi Sam,
        I remember you told me some things about my own Fluke. I evetually took it to Branom Instruments, here in Seattle and they took care of me as they sell Fluke equipment and service. They dont restrict their business strictly to Fluke however.  The price for me to have them check it was worth it, mine needed nothing.
         You ought call them, I think if it needed repair the cost to fix it would be about 75% that of a new one,  max... You can find them on the web and one number to call is 1 800 767 6051.
          They repair 'process control instrumentation' as well as testing equipment including DVOMs, transducers, etc.
 For sure you can look for a company that repairs and calibrates instruments.

Title: Re: firstlook
Post by mwebb on Aug 19th, 2007 at 5:57pm

jarvissamuel wrote on Aug 18th, 2007 at 6:55am:
Hi Michael

I have a question.  What benefit does hooking the pv350 to bat neg?  Everytime I have used it I have hooked directly to the scope leads.


for better resolution with the PV350 i use the "metric" setting .
 
the adapter i made to use the PV 350 threads into the spark plug threads , a 1/2" copper pipe with a quick disconnect fitting on top for the PV 350 , it electrically connects the case of the PV 350 to the spark plug threads ... so  the benefit is that if there is a voltage drop problem on the ground side , it puts RF hash in the waveform , so if you ground the PV 350 to the battery negative , it helps to diminish the RFi hash ...
i have take the liberty of overlaying one of my good running compression awo files on your capture , you have an rfi problem but  your resolution is not good either ... what kind of adapter have you fabricated to use in the spark plug thread ?  
Fluke_pv350_s_jarvis_autonerdz_ani.gif (116 KB | )

Title: Re: firstlook
Post by jarvissamuel on Aug 20th, 2007 at 6:47am
Thanks Mike I will give it a try.  My apadter is just hose connected and clamped to the hose from my compression tester.  I may have been having a problem wiht my usb connection on my pc as well I went to use the scope and the voltage was reading 5v less than what it was wiggling it would correct it.

Here is an image of when the pv350 was apparatly working
97caravan3L_camphasing.gif (50 KB | )

Title: Re: firstlook
Post by mwebb on Sep 2nd, 2007 at 6:08pm
   

using AES ANNOwave for the graphics and Pico 6 scope software.

this BMW with M54 6 cylinder engine has a COP ignition system , AceMisfire can find misfires pretty easily , but if you dont have Ace Misfire yet.... .

you can stretch aluminum furnace tape across the tops of the COP coils , then connect the secondary lead to the furnace tape taking care to not touch ground with the tape or test lead .
use primary from the #1 coil or primary current from #1 coil to sync and   - unfortunately the 2ndary spark waveform did not show the misfire this time ? but the FLSe pressure transducer in the exhaust does .
,

i have overlayed a running compression waveform and matched it to equal 720 degrees of the image , so that 720 degrees in the image matches 720 degrees of running compression waveform length ,
then i drag the running compression waveform so that the Exhaust valve opening matches the Long line misfire , drop in some cursors to clarify everything and shazam one misfire is on cylinder 4.
at 2k rpm no load . this spark system is similar to ford multi strike at idle , this is about 2200 rpm.


on this car , you can also connect to the primarys with a PRB and get spark primary in parade  
DBL3501_02_325i_87899_miles_IMM6.gif (106 KB | )

Title: Re: firstlook
Post by mwebb on Sep 2nd, 2007 at 6:10pm
 wrong image above ,  
DBL3501_02_BMW_325i_M54_LL_M_cyl_4__2_2k_ani.gif (89 KB | )

Title: Re: firstlook
Post by mwebb on Sep 29th, 2007 at 7:27pm
1991 BMW 535i  M30 engine ,  
2k rpm , spark does not show misfire , but FLSe does .... weird ? i also have waveforms that show misfire that spark and o2 do show , but FLSe does not ?

first set the verticle cursors so 720 degrees in cursors equals 720 degrees in waveforms, then i have set the cursors by swag to kinda sorta match the valve opening / closing  events then added on 30 degrees in front to allow for spark advance at 2k rpm , another swag , then over lay the the cursors on the waveform and drag it around until the valve open close event lines up with the LL misfire , look where spark should be ,    and shazam , there it is .   cylinder 4 .
                         i'll be dipped in fried bat poop .
1991_BMW_535i_M30_wnew_2ndary_LL_misfire_ani__gif.gif (102 KB | )

Title: Re: firstlook
Post by mwebb on Oct 6th, 2007 at 7:43pm
here is a vacuum leak , picked up by Mr o2 sensor but although the mixture is leaned out by the vacuum leak , it was not leaned out enough to cause a misfire as shown in the FLSe waveform .
disconnected purge vacuum line before purge valve , 00 saturn SL1 .  
2000_saturn_SL1_intake_leak_on_purge_valve_cyl_2_ani.gif (132 KB | )

Title: Re: firstlook
Post by Alex Richards on Mar 25th, 2013 at 9:01am
Hello all,

Relatively new to the forum and hope you don't mind me bringing this one back from the dead, but I have a weird vehicle waveform that I'm attempting to figure out...

This is a 2001 cavalier 2.2L LN2 OHV engine, Firing order is standard 4 cyl stuff, 1,3,4,2

I hooked up the Firstlook to intake vac, have the sync hooked up to #1 coil (waste spark system so you'll see #4 fire 360 after) and green is system voltage while cranking.

This is a WOT cranking test, fuel disabled

Power balance says cyl 3 is the issue, wave form if I'm looking at it right says Cyl 2 is...

Not sure what to do here, This is a slight misfire at an idle, seems to smooth out while driving or if it's revved off idle.  Really want to use this for a presentation I'm doing Friday.


https://www.autonerdz.com/cgi/yabb2/YaBB.pl?action=downloadfile;file=crank_voltage-firstlookintake-cyl_1_secondary.psdata (11329 KB | )

Title: Re: firstlook
Post by crackerclicker on Mar 25th, 2013 at 12:54pm
Hi Alex,

You'll probably get more responses if you open a new thread for your case.  From your description of #3 failing the power balance, I'd guess that the intake wave is showing you that you are getting pressure in the intake during #2's intake stroke.  That pressure may be coming from a leaky #3 intake valve during #3's power stroke.

I'm busy right now, but when I get home I can put up an image that can show this better.  Perhaps by then others will have seen this, and can chime in.

Title: Re: firstlook
Post by crackerclicker on Mar 26th, 2013 at 8:54pm
Sorry Alex, I meant to do this yesterday. 
an_fl.jpg (91 KB | )

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