need expert help diagnosing misfire

[Ickle]

rite its on a x reg scenic k4j 1.4 16v petrol with 80,000 miles
has a slight misfire that you can hear by engine and by exhaust,
changed coils and injectors with known working parts out my car to rule that out and its still the same,
next done a compresion test that comes up 200psi on each cylinder, so seems no prob there,
done breather test on header tank to rule out headgasket and that seems fine,
checked electrical conectors on coils and injectors and they have power to them fine,
has no milky residue in oil filler and is not losing water,
could this be a headgasket blown between cylinders where the water is not getting to and its losing compresion here?
also if you unplug conector for injector 1 (gearbox end) it does not affect the running any different

any help appreated
thanks

 

[VXR killer]

Ht leads, soark plugs?

 

[Ickle]

Forgot to mention its had new plugs, it doesent have ht leads its got individual pencil coils

 

[stephen chadwick]

also if you unplug conector for injector 1 (gearbox end) it does not affect the running any different
thanks

surely youve found your problem then? is it intermitent or all the time?

 

[Ickle]

It is all the time on idle when its cold, soon as it warms up or is reved its fine but then as it gos back to idle same problem again, also driving it is fine no loss of power or stutters or anything.

 

[Dan519]

It is all the time on idle when its cold, soon as it warms up or is reved its fine but then as it gos back to idle same problem again, also driving it is fine no loss of power or stutters or anything.

seen this before on a 172. I found it to be dirty injectors that didn't close fully so the engine would idle with all 4 injectors unplugged.

 

[Ickle]

But ive tried the known working injectors out my clio that are the same,
Mite try swapping them round now tho and c if it stays as a problem on that cylender or moves to another

 

[Dan519]

needs plugging in to proper diagnostics at this point

 

[Ickle]

Had it on a snap on diagnostics that come up with polluting, whats next?

 

[Jonny1*2]

Lambda sensor probably

 

[Ickle]

Pre cat or after cat? Also how much are they?

 

[Kev_md]

Try an Italian tune up.

 

[Ickle]

Any1 else have any ideas?

 

[Chapster5]

Pre car lambada sensor I'd reckon maybe idle control valve?

Nick

 

[Ickle]

Thanks ill try thease next, also engine management light is on

 

[MicKPM]

The MIL will most likely be on because of the poor idle/missfire. I've got a 1.4 16v Megane II in the workshop waiting for me on Wednesday with exactly the same fault so will report back (unless you manage to resolve it between now and then).

Mick

 

[Ickle]

Yea that would be good if you could let me no what you find, thank you

 

[scotty2hotty81]

If its not pre cat lambda then everything has been covered bar ecu, peugeot ecu's get spiked and cause misfires.

 

[MicKPM]

The Peugeot issue is caused by several things though; such as water ingress, and lack of surge protection... the cars are still coming out with the same silly issues to. This issue will be something silly i suspect.

 

[valver2012]

The MIL will most likely be on because of the poor idle/missfire. I've got a 1.4 16v Megane II in the workshop waiting for me on Wednesday with exactly the same fault so will report back (unless you manage to resolve it between now and then).

Mick

Hi Mick, I have a similar problem with a 1.416v k4j engine. I plan to replace the 02 sensor on Saturday.

How did you fix your one??

Cheers

 

[MicKPM]

A faulty MAP Sensor was the cause of my naughty K4J (Megane II) idle missfire.

 

[Ickle]

Thanks mick, ill try that along with a new lamba sensor as that seems to be a popular problem

 

[MicKPM]

I'd check your injectors also. I had two Clio II's in yesterday both in need of one injector each.

 

[Bobby.]

You could just pay Renault £60 odd for a diagnosis check instead of wasting money on sensors etc. Shooting in the dark.

 

[Ickle]

Mick we tried the injectors with working ones out my clio and tried the scenic ones in my clio and they are fine, but thanks,

Renault enthusiast i had it pluged in to snap on diagnostics and it came up as a code for pulluting, so gotta be a lamba sensor or similar, thanks

 

[valver2012]

Hi Ickle / Mick, I have exactly the same problem as you. I be interested to see how you get on.I tried a Map sensor but that did not work, so I have ordered a new 02 sensor. Hope to get a chance to fit it on Saturday so I let you know if that works.

Let us know how you get on!!

Cheers

 

[MicKPM]

Have you had any diagnostics carried out yet on the vehicle? Don't replace parts like Map sensors on a whim mate as they're not cheap!

OP - Have you checked the coils and confirmed them as working yet? The K4J does use these stupid things.

Mick

 

[valver2012]

According to the service history the coils were all replaced 10k ago by renault main dealer. I tried each one by running the engine and pluging each one out and they all effect the idle ie make it worse and the fact car drives fine I ruled them out?? Would I be right saying that!!!

I have just received a new Bosch 02 sensor in the post today so I am hoping to replace on Saturday. I also have a full set of injectors which I got from a donar megane k4j so if the 02 dont cure it I will fit those and if that dont work I going to dump my girlfriend as its her car and its costing me a fortune.!!!

 

[Ickle]

Lol thease problems are a nightmare, mick we used the coils out my clio that we no work so ruled that out, car is now gonna be scraped as its my girlfriends dads and between 3 of us didnt no what was causing it and her dad was adament the headgasket was blown between 2 cylenders so striped it down last nite and cant see any breaks so gave up and is scrapping it, although im sure its a sensor as the problem goes when reved, oh well will never no what it was now.

Valver2012 hope u find ur problem with out to much cost on it, let me no how u get on

 

[Jonny1*2]

lol. I can't believe they ripped the engine apart without getting PROPER diagnostics done. 10minutes on clip and you would have been able to find out the source.

 

[Ickle]

I no, waste of a car, on the plus side i got a spare engine for my car now if anything goes wrong lol

 

[lemonnobby]

alternators can effect idle on megane 2

 

[valver2012]

ya I will Ickle, ive replaced the plugs airfilter cleaned the throttle checked for air leaks, swaped the step up motor, the last 2 things is the 0 and the injectors.Ickle did you change the 02 sensor at the manifold on the back of the engine??also the socond one is on the exhaust half way down. Thats my next job!!! I cant understand it as I had a megane coupe k4j which I bought new 10 years ago and the only problem I had was a set of coils in 3 years that I had it. It always idled perfect!!

 

[MicKPM]

alternators can effect idle on megane 2

This is very true... and a good point. There was a TSB about it I believe and requires a new alternator and some wiring IIRC

 

[Ickle]

ya I will Ickle, ive replaced the plugs airfilter cleaned the throttle checked for air leaks, swaped the step up motor, the last 2 things is the 0 and the injectors.Ickle did you change the 02 sensor at the manifold on the back of the engine??also the socond one is on the exhaust half way down. Thats my next job!!! I cant understand it as I had a megane coupe k4j which I bought new 10 years ago and the only problem I had was a set of coils in 3 years that I had it. It always idled perfect!!

No we didnt change any sensors, i wanted to swap the lamba and map sensors but he woudnt and is to quick to strip it down, i said from day 1 its only gonna be a small fault like a sensor or wire and it wont be as involved as mechanicals,

Yea try the sensors it really cant be much, ive had my clio 3 years only had 1 coil fail and tdc sensor so cant knock it aand its on 60,000 miles now

 

[valver2012]

No we didnt change any sensors, i wanted to swap the lamba and map sensors but he woudnt and is to quick to strip it down, i said from day 1 its only gonna be a small fault like a sensor or wire and it wont be as involved as mechanicals,

Yea try the sensors it really cant be much, ive had my clio 3 years only had 1 coil fail and tdc sensor so cant knock it aand its on 60,000 miles now

Meant to ask you as well, did you inspect the T Belt!! I was talking to another guy who had the same problems and he brought the car to Reno main dealer who fixed it and told him it was the fact that his timing belt was missing 2 teeth and the lambda was faulty. that cured it for him but as he said if the belt was missing teeth it should have effected it at all speeds and not idle so he reckons it was the Lamda but the garage had changed the belt first and when that didnt work did the Lamba and charged him for the lot!!

 

[Ickle]

No didnt inspect the belt but did check the timing with proper tool

 

[valver2012]

Well lads finally got it sorted.:race: She ticks over now like a Swiss watch idles perfect. I replaced the 02 sensor. Took her a run there now and the car reminds me of when my own one was new.

When I took out the old 02 sensor it was black with sut. The car has like yours Ickle has 78k on the clock and I know you have been through the car except for the O2 Sensor!

Thanks lads for all the help!!!:cheers:

 

[Ickle]

Well done, good to get progress and glad ufixed it and are happy with it

 

[Techz]

Hi gents, while we're on the topic I'm having a similar issue with my 2l (F4R) I've diagnosed thus far that I have a misfire on cylinders 1 and 4 due to no voltage at the coil pack leads, I have changed all 4 packs and a map sensor before this. Will only fault however after a few mins of driving, get volts to all 4 on startup and for as long as I idle in the driveway. Was wondering if anyone had some ideas