Random Misfiring

[Penedo_Aero]

Hi!
I have been trying to find the cause of a missfiring for weeks and I am kinda lost. I brought the car to different garages and they told me opposite things like:
-Compression is fine so it is a electrical issue (Garage1)
-There is a compression issue in cylinder 4 (Garage2)
-There is a compression issue in cylinder 2 (Garage3)

The bolt of the coil in cylinder 1 is loose. This bolt is shared with the camshaft sensor so this is also a little bit loose.

If you have some idea of what to try please let me know!

Cheers

 

[Sean197]

If you can get it plugged into CLIP (Renault diagnostic machine) it'll give you a fault code, and you can start from there.

 

[PITA]

Hi!
I have been trying to find the cause of a missfiring for weeks and I am kinda lost. I brought the car to different garages and they told me opposite things like:
-Compression is fine so it is a electrical issue (Garage1)
-There is a compression issue in cylinder 4 (Garage2)
-There is a compression issue in cylinder 2 (Garage3)

The bolt of the coil in cylinder 1 is loose. This bolt is shared with the camshaft sensor so this is also a little bit loose.

If you have some idea of what to try please let me know!

Cheers

The cylinder with the dephaser solenoid is number 4, they’re numbered from the flywheel/gearbox end.

What kind of misfire is it? Random, high RPM etc.

Have you checked the usual suspects of coils, plugs and cam sensor?

 

[Penedo_Aero]

If you can get it plugged into CLIP (Renault diagnostic machine) it'll give you a fault code, and you can start from there.

Thanks for the quick reply!
I did it already and the error that appears is missfire in cylinder four.

 

[Penedo_Aero]

The cylinder with the dephaser solenoid is number 4, they’re numbered from the flywheel/gearbox end.

What kind of misfire is it? Random, high RPM etc.

Have you checked the usual suspects of coils, plugs and cam sensor?

Hi thanks for the quick reply!
I have replaced the spark plug, coil and map sensor already and same thing! The only thing I found is that when I moved the camshaft sensor the car rev up suddenly although It didn’t work fine. The misfiring happens in all the range of rpm. And as the guys from the garage told me about a compression issue I thought on a bigger issue

 

[Foxspeed]

so what is the "compression issue" then???

leak down test / wet compression test - results etc???

is the plug sooted up???

 

[Penedo_Aero]

Everything I know so far is that compression is low. One of the garages told me that it was in cylinder 4 and the other one in cylinder 2.
Tomorrow I will do the compression test by myself.
Any advice/tip for doing it properly?
Thanks!

 

[Foxspeed]

make sure throttle is fully open
spin engine over for same amount of time each turn
once done it dry...put a few squirts of oil down and do it again and see if there is any difference... (if its the rings the wet test should be higher psi)

 

[Penedo_Aero]

Thanks for the tip!
I have checked the compression and the results are:
-Cylinder 1: 150psi
-Cylinder 2: 150psi
-Cylinder 3: 150psi
-Cylinder 4: 0psi

I havent tried the oil thing yet!
Some idea about what can cause a suddenly lost of compression? I am guessing a valve?
There is no any smoke from the smoke btw

Thanks

 

[PITA]

Sounds like it’s time to take the head off and have a look. You’re not fixing that without taking it off anyway