I just did a search for TSB;s pertaining to your concern and came up with a spark knock related to the rear knock sensor.
Due to it's location it is easy to fill cavity with water from hood seal causing the sensor to not work correctly and or set a code P0332.
I have ran across this on Trucks but not in your application.Although it does list your application as a candidate for this condition.I would view a scanner and look at the knock sensor Pids along with computer advance and determine if this is indeed a spark knock you are hearing(piston slap).
All I got.
Post up some more info and people will give you more direction.
Ronnie.

Another log...

The "rattle" occurred just about where the vertical line cursor is.

I'll post more info as I progress...

Carl Grotti wrote on Mar 17^th, 2008 at 8:20pm:
Hi Carl,

I'm using a scantool called "EFI Live" which consists of a hardware module (smaller than a cigarette packet) and software (which produced the graphs you see above);

the module can record in black box mode, or with a PC/laptop it does "live" mode;

If you want the website link, please let me know.

I'm an electrical engineer, but I used to work in my Dad's transmission shop (family business) a long time ago.

Thanks
Joe

Questions:
- is top engine cleaner one of the fixes for knock...?
- if so, what is the correct way to apply TEC...?

Quote:


Yes.

Quote:


I don't know, but it sure can make an engine Ping.  For example it is common for some Chrysler V8 engines to begin to leak under the intake and ingest oil.  Often times not enough to really make it smoke or show other evidence.  Unmanageable engine ping is one of the clear symptoms though.

I can see by your nice graphs that the knock retard is kicking in.

Quote:


Sounds like you have already considered carbon knock.  This can make some really bad sounds and is often related to engine speed and load.

I have used the TEC many times with excellent results.  I pour it in while keeping RPM just high enough to prevent stall and, when I get the the bottom of the can, pour the rest in quickly enough to snuff the engine but not so fast as to hydro lock it 

Then let set overnight or all day.  Then take it out somewhere where you can blow it out with out getting a ticket for obliterating the traffic visibility for miles 

Quote:

How does a shop or dealer service dept. do this...? 

Dave,

Thanks, I'll look into Run_Rite.

Ve tool as in "virtual ve tool", no I have not used that;
I have used their flash/edit tool (which is GM specific) on another PCM.

Thanks,
Joe

Sleuth,
I heard that water trick only worked with leaded gasoline , due to the chemical make up of the carbon.

I havent personally checked to see if this was true though.

Qwix

The MAF is in front of the TB... would I spray(mist) water directly into the MAF...?
I don't want to wet the MAF elements, I don't know if they would be harmed.

I could remove the MAF (it seems to run without the MAF) and spray water into the TB like that.

So, I would set the spray bottle to fine mist, and spray water in as I open the throttle wide (same as yo would on a carburettor)...?

Oh... that only works for leaded gasoline...?  I can try it and see.

Thanks.

Yup, so now you wait till morning and "drive it like you stole it" out of your neighborhood onto a bypass. The chemical has probaly soaked down into your oil rings(gonna clean them out) so when  do this type of treatment I always level my speed off(once all the smoking is done) and drive between , say 40mph to 60 on a gentle increase, then back down to 40, gently for several miles to seat the rings back in There is a chemical called "Chemflow" that works well for getting the sludge out of piston rings, have used it many times for stuck oil rings in Chevy`s without pulling the engine down--using the procedure mentioned by Tom. As for carbon, the best way I have found is to use a chemical(like run0rite etc..) and administer it into the intake system as a mist loading the engine down slowly, then tapping the rpm to 2-3 k a few times, letting it load back up and continue till you use all the chemical--when she starts to load up and miss--rap it up a few k-letting it load back up a bit--then continue. Clear your codes and adapts. I have never seen the runrite  hurt an o2 sensor or Catalizer. "Tune-up in a Can" brings back the part throttle response that seems to get lost with carbon buildup around the valves and piston tops. Never seen a customer balk at the bill when administered correctly either.Sometimes , depending on the engine etc, I move the connection around to make sure I get the cleaner throughout the entire engine, the pvc hose sometimes will not allow you to get good cleaning on the front of the engine
Dave

Does it do it when it is COLD? Is it overheating? No water on the MAF.err.Sure if your neighbors can stand it, Guess you`ll have to say it "Mosquito Control" this time? Might want to take a look at the timing chain for wear perhaps? Dunno...at wits end. Perhaps some more and diffrent patterns to Look at, I`m sure someone will pipe up when they see something. Wonder what the Cam-Crank relationship is at when it does the deed?

Dave

This just a guess based on description and not being able to hear the noise in person. Have you checked the Bendix drive on the starter? They can get weak and the gear will move when the vehicle is accelerated and hit the ring gear.

Starter and flexplate are both good.

Quote:

Dave,

Good thought, shows you're thinking... 

My car is stock, and has always knocked (the dealer technicians couldn't solve it)... I have been monitoring AFR (via exhaust lambda) and it is not lean... I also been monitoring ignition advance, and it looks normal (does not seem to advance excessively).

I have been following up on the suggestions as time permits (I have a wife and a job), and I do appreciate everyone's suggestions, thanks to all.

Next step is to take care of oil thru PCV and potential knock sensor problem (according to TSB).

I am trying to hook up a scope to record while driving...

Good thought tho... I'll do some research into IAT/MAP/MAF effects.

Thanks,
Joe

Quote:

Dave,

I'm going to do something like that, a oil-catch container inline with the hose feeding the PCV valve...

I'm also thinking to fit the later model valley cover that has integral crankcase vapor collector... GM changed from valve cover to valley cover crankcase vapor collection because of oil ingestion... this will also give me the opportunity to inspect/replace the knock sensors, since all of this requires pulling the intake manifold (which on a late Firebird is tucked under the cowl...    )

About the pressure relief valve in the fresh air hose from the air cleaner to the crankcase: are you saying to allow the crankcase to build 4-6 psi of vacuum before the relief valve opens...?  i.e. so the crankcase is always under vacuum and never at atmospheric pressure...?  Am I understanding correctly...?
Hmmm.... I'll try that, thanks.   

Can spark plug gap influence knock...?

There's a GM TSB 03-06-04-060A saying to use iridium plugs gapped at 0.040" (instead of platiunum ones gapped at 0.060").

Does anyone know why the change...?

Dave, thanks, I'll read that link.

Quote:
Hi Dave,

Thanks for asking...

I applied TEC one time only, and it was a big improvement, altho on a hot day in slow traffic it will knock slightly.

I still need to check my plugs again, and to check my knock sensors (under the intake manifold which is tucked under the cowl-overhang; I'm waiting for a manifold gasket set; the cooling system does not pass thru the manifold, so I am thankful)...

And my Mrs makes sure to keep me busy with other things...

The 'rattle' seems to have moved from low range (1500 rpm) to mid range (2500 rpm)... it happens as you increase throttle thru low range, and it then stops as you keep increasing throttle to mid range.... I could be looking in the wrong place, but it does seem to me to be engine related... it's annoying, and I'm wondering what it is...

I have been under the car with a rubber hammer, I found this:
- the stock catback is sliding back from the Y pipe... I tightened the stock band clamp using a large breaker bar, but it is still sliding back... the Y pipe OD must have crimped, I'll expand it back out with a pipe stretcher tool;
- the O2 sensors (four) have a ring (for breathing fresh air I assume) which rattles and vibrates, but the sound it makes is very low;
- I need new motor/trans mounts, they're not broken but they're worn/soft/stretchy;
- the whole exhaust system has a very light rattle, but it doesn't seem to come from the cats;

I have been logging with the scantool every day and studying the logs; I'm logging pids like cylinder airmass to see if there's an abrupt change that may cause timing or AFR to change.

I have a Fluke color scopemeter (which I use for electronics) which I'm trying to connect up to the various sensors to take a recording when the rattle happens, but it's not so simple to figure out how to probe without puncturing wires (I'm a bit apprehensive about that) and how to run the test leads from engine bay to driver's seat;
I'm not too happy with the Fluke, it's not easy to use and the recording/playback user interface isn't very good.
I'm just about to buy a Pico Quad from AutoNerdz... 

Cheers,
Joe