Hi,

I´ve got a Clio here what has a misfire,
at idle i can clearly hear it plopping in the
exaust.
The P0350 is coming back always after a
short time, and sometimes i get one to
the Throttle Body Circuit.

I took a sample of the Coil pack at idle and
with a snap.

Could that be the Prob already ?

Thx Chris

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Christian, my not being incredibly well versed in that particular vehicle platform, I will need a some time to get code description and set criteria. :'(  I would think that seeing which cylinder (s) were guilty would be on the first order of business list, so a sync on #1 Secondary event ("I would think,") be necessary. The current ramps appear unremarkable and taken at a pretty low sample rate, (To My Less than Proficient Eye) so you may need a primary voltage shot to get an idea of what is going on at the end of the trail. Then if that analysis dead ends, you can look at relative compression, (always done early in the process for me, with a sync so I know who's home and who ain't) fuel rail pressure drop, etc. Always remembering that making an engine run is just like lighting the BBQ Grill you need, the right Fuel, Air (Under Correct Pressure ) and a Lighter. The best of Luck.

Rel. compression i took a look also in the beginning, but
i don´t think the is any problem.
Its not running real bad, but now and then the is
a miss.Sometimes more,sometimes for 10 Min nothing.

Here is the rel.comp shot...

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Christian I just did a quick search for that code and the only thing that came up was done in German, so all I can say is it looked like a Throttle Body :-/  http://www.bing.com/videos/search?q=2001+Renault+Clio+p0350+code&view=detail&mid=8FDCB38D341F2307B3EC8FDCB38D341F2307B3EC&first=0.

My AllData has Nada, Zip, Zilch, information on that platform so I would have to go Old School, but armed with the Throttle Clue, possibly re-vamp my testing strategy.

Your current ramp capture I don't like. The turn on as well as the turn off are not clean like I would expect them. I don't see these cars so would ask for a little more to bring at least me up to speed.

Can you probe ignition coil primary?

How many cylinders is this engine?

What type of ignition system are we talking about? Coil with distributor, DIS or COP?

Your relative compression looks fine to me.

Its a 4 cylinder with one big coilpack and 2 coils
in it. Here are 2 shots, maybe you mean this.

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Spence wrote on May 6^th, 2012 at 9:46am:

Your current ramp capture I don't like. The turn on as well as the turn off are not clean like I would expect them. I don't see these cars so would ask for a little more to bring at least me up to speed.

Hi Spence, I wasn't wild about the Current views either and couldn't see the sample rate, but after your post I did zoom in and am seeing about 11us cut off, I'll have to go back to my Nerd series for another refresher on the requirements (At my age, every day is like starting over).  Is this what you see also?

After a little closer look it appears to cross "0" close to 11.4us

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Hello Christian,

I reviewed all of your captures so far and your burn time is very short. Your burn time at idle is only roughly 600us and when you snap the throttle it is only 290us.

The burn time should be around 1ms.

As for primary drive (coil turn off is fine at 11.2us).

Have you removed the coil pack and checked for coil output and see how far it spark jumps with a spark tester?
The rough rule of thumb is 30kv (13mm or 1/2 inch).

Your power to the coil pack looks good and relative compression looks good.
The ground is touch and go blue trace is 440mv (0.44V) and red trace is 540mv (0.54V) but the amperage looks okay.

I have attached some pictures of my measurements.

Anthony Lamb

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Hi,

Thanks, so you don´t think it would be the Coilpack ?
I don´t have a sparktester in this way,
but i just ordered one. It should come in a week.

The Coilpack looks fine so far, no cracks or
bay spots anywhere, the cables are fixed inside,
so i can´t remove these one on one.
The contacts at the Coil and the Cable also look
fine as well.

How many miles on engine?

210 000 km = ~ 130 000 miles.

I would check your grounds if they test out okay then i would pull the coil pack out and use a test light on the coil secondary and see how far it jumps to the test light (don't let the test light touch the coil post) with someone else cranking the engine and slowly move the test light away from the coil and repeat for both coils. If it doesn't jump 25mm it is defiantly the coil pack.
Also i made a mistake with how far it should jump it is 25mm or 1 inch.
Also i forgot to mention you may have to run a ground from the coil pack body to engine ground when you remove it to test it.
Good luck

Hopefully this picture will help explain how to test the coil pack a bit better. (coil is a old denso one i had laying around). Have the test light clip on engine or battery ground.
Also don't forget to check the battery terminals for corrosion.
Hopefully this helps out a little bit.

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Anthony , in every market exist a suitable and professional spark tester for under 10euros....

Most of them have possibility to adjust air gap and have pointers  how much kV is for every distance. And probably the most important thing is You can't get hit by secondary ;)

Coils on that particular engine last around 50.000km mainly because not all services have tool for spark plugs mounted on it. Result is over load coil because it has enormous resistance between spark plug electrodes. Some of those was found with gap 2.1mm , if you add extreme temperature  HT leads are exposed to( engineering on that engine is not great at least ;) )  and no possibility to remove them from coil and check for internal open circuit you get P0350 and You should always change spark plugs together with coil  ;)

One more thing to look when you have misfire on 1.2 16V . Lot of services just pull leads straight up when changing plugs instead of  twisting them before pulling and leads get damaged so its good to look for sparking traces in spark plug holes ....

Hey Branko
I was just showing Christian another method as he doesn't have the right tester at this moment in time. Personally I always use a adjustable spark tester.
It's always fun when you do get hit by a secondary. :D

Hi,

Thanks for the good Idea.
But i have a adjustable sparktester ordered, so
i will test it with that when its here ;)

The Spark plugs are about 1 Month old, they
changed them without a result, so i thought
about the coil.

I will look in the rubber hose to each Plug if there
are any traces and if they fit tight.
And then i will take a pic of the coil when the
Sparktester arrives.

Then i will see if it gets a new Coilpack ;)

I can tell you that you should buy it just on model make without even codes pulled out  :D  I have about 2 every week with same issue ;)   BAD quality and nothing else there

Hi Christian

Check the end of the plug lead about 20mm from the spark plug, where the boot narrows down

You may find a mark about the size of a pin head where the spark is tracking through.
HTH

David

I looked very caregully to the boots, but couldn´t see
any thpe of spot, crack,trace or bad material so far.
But we will see when the Tester arrives, then the
boot ist sparking outside..

Although I know jack crap about this car, I was looking through your captures and noticed one point that looked different than some of the others.  Here are a few pictures to look at and some thoughts on them.  It's hard to say for sure, but I may have stumbled upon the point at which there MAY have been a miss.  Why it missed ( if it actually did ) is still up for grabs.  Do you have a pressure sensor that can be deployed into the exhaust in order to verify that a misfire is actually occurring during your captures???

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Sparktester arrived - 25mm from Pin to Pin ?
Never ever....15mm yes, 20mm - thin Line, not constant spark, 25mm - no chance

Yep 25mm from pin to pin or on the spark tester where it says 30Kv.
Well done if you put a coil and leads in it should be a fix.

I Ordered a new Coilpack, we will see ;)
In the Time i took some Secondary-Pics,
and i saw one event repeating, but i don´t know
what i would name it, or if it´s nothing.
I would say "strange" - two other Cars don´t
have it.

Maybe this is gone with the new Coil as well :)

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Coil didn´t help - it was the ECU that was bad.
New one in and everything is fine.

Hello sorry for the late reply.
Strange it was the ecu and not the coil.
Does the old ecu have look anything out of the normal?
Can you post some picture of the ecu circuit board?

Outside you didn´tsee anything.
No bad Pins or anything like that.
No, the old ECU went into swap at the Dealers,
so we can´t open it anymore.