Clio 1.2 16v misfire, is it the coil pack?

[victorimba]

Greetings,

Searched through the forum and found many similar threads but none that completely matches the issue im having with my car which is a Clio mk2 1.2 16v from 2006 (D4F-722).

The problem at hand: the engine is misfiring on cylinder 3 (check engine light is on and occasionally flashing) and I feel like it at its worst at start up and gets a bit better after a few seconds, still runs rough on idle though. First thing I checked was for spark via a spark plug tester (a light that connects to the plug and spark wire, like this one: ) and it flickered consistently when the engine was running. I went on by examining the injector and it seemed fine after some testing with a multimeter and ocular inspection.

Then I found this video:


Since I dont have the correct socket for getting the spark plug and doing a compression test out I went back to testing the coil pack. Everything checked out fine according to whats being stated in the video EXCEPT for the resistance measurements between leads 2 and 3, which should be about 9.6 Kohms. Mine showed "OL (open loop)" no matter how i probed and positioned my testleads.

So, my question is: could the coil pack be the reason for my misfire even though I got a consistent spark with my spark plug tester or am I doing something wrong?

 

[Martin_172]

If it's an intermittent misfire that's a hard thing to see in a spark plug tester.

They seem to be worse at part throttle when they start to fail and behave at full throttle.

Could packs are VERY common for failing on these engines

 

[JamesBryan]

You mention the EML flashing occasionally.

If it's anything like the RS's, it's usually a fuel injector.

 

[victorimba]

If it's an intermittent misfire that's a hard thing to see in a spark plug tester.

They seem to be worse at part throttle when they start to fail and behave at full throttle.

Could packs are VERY common for failing on these engines

I see. Anything else you know that can be done to test this as a DIYer?

You mention the EML flashing occasionally.

If it's anything like the RS's, it's usually a fuel injector.

Could be. I've measured resistance in cylinder 3 injector, made an ocular inspection and found no crud etc - I also pressurized the system for a few hours and saw no leakage and the spray pattern was not obviously deviant from the other injectors. I guess more extensive testing can be done with special tools but right now im not leaning towards an injector issue.

 

[Martin_172]

You mention the EML flashing occasionally.

If it's anything like the RS's, it's usually a fuel injector.

it will also flash with a coil pack failure when it detects a destructive misfire

 

[victorimba]

For some closure on this thread. I got the correct socket and performed a dry and wet compression test which showed low compression on cylinder 3 (about 75 psi compared to the others around 160). Could be multiple errors but thats probbly why it misfires.

 

[victorimba]

Back again. Took the top off and found a burnt exhaust valve that was leaking. Also found a very pitted camshaft and lifters/tappers. So, im looking at replacing the camshaft while im replacing that valve. Thinking of buying a used shaft and got some feedback on another forum that the 712 and 722 engines might share the same camshaft and tappers/lifters, which would make the search a bit easier. Can anyone here confirm if thats the case or not?

 

[Meic]

Back again. Took the top off and found a burnt exhaust valve that was leaking. Also found a very pitted camshaft and lifters/tappers. So, im looking at replacing the camshaft while im replacing that valve. Thinking of buying a used shaft and got some feedback on another forum that the 712 and 722 engines might share the same camshaft and tappers/lifters, which would make the search a bit easier. Can anyone here confirm if thats the case or not?

Hi, have you made any progress with this fault?

 

[victorimba]

Hi, have you made any progress with this fault?

Sure. Had low compression in cylinder 3 due to a burnt valve and at the same time a faulty ignition coil. Swapped both parts and it now runs ok. Fyi the d4f 712 and 722 does not share the same camshaft.