ENGINE MIS FIRING

[Robert63]

Hi All I have posted this problem previously and have had plenty of advice on here as to what the problem could be. The car in question is an 04 plate 2.2 zed. I have had this misfiring problem since February, the rev counter fluctuates between 500rpm and 1000 rpm when idling, and it is a heck orf a job to keep the engine running. I had an diagnostic check done with adelphi software and it produced an error code 2783 Air Mass Meter Hot Film Intermittent . So I replaced the MAF Sensor the error code reset and didn't come back however the engine ran just the same.
I then noticed there was a tear on the Air inlet hose, so that was replaced however the engine ran just the same. I have today replaced the cam shaft cover gasket and fitted a new battery and a new set of plugs and the engine is still misfiring. I tried driving it down the road just to see I only went a few yards before the car was jerking as if there was kangaroo juice in the tank, so I reversed it back into the garage.
So to list the parts replaced : Air inlet hose, MAF Sensor, Cam Shaft Cover Gasket, Battery, Set Of Spark Plugs.
I am really at a loss now and don't know what to check next, all ideas would be greatly appreciated.
Many Thanks

 

[sw4nny]

Coils?

 

[Smartbear]

Have you scanned it again? I’d also run it with the maf disconnected & see if there’s any change.
Rob

 

[tomrdy]

Sounds like it could be a coil to me. When you replaced the sparks, did you inspect each coil?

I had a faulty one for ages and the car would stutter randomly and go away if I turn the car off and on - never threw a code until one day, I just kept trying to drive it while it stuttered and eventually went into limp mode. Then it turned up misfire on Cyl 4.

The coil looked fine on initial inspection, but then i discovered a tinnnnny chip-away at the bottom of the rubber boot. Replaced it and alls well.

 

[colb]

Coils worth a check starting by swapping any suspect coil if you have a code for a particular cylinder with one of the others to see if the misfire code follows the change, if it follows then change that coil for a replacement. You might also consider a smoke test on the engine to see if you have qany further air leaks, The Maf is removed and smoke pumped into the intake hose sealed with a rubber glove streatched over it and the smoke blown in through a hole in one of the fingers. Best done with the throtle opened so the smoke gets through quicker. If you have any leaks in the system the smoke will be seen escaping from the source. These engines require a completly sealed vacuum system to run correctly, find air leaks visually without smoke can be difficult. How to smoke test on youtube, quite simple to build your own kit as retail units are pricy.

 

[AveZ4coop]

Sounds like it could be a coil to me. When you replaced the sparks, did you inspect each coil?

I had a faulty one for ages and the car would stutter randomly and go away if I turn the car off and on - never threw a code until one day, I just kept trying to drive it while it stuttered and eventually went into limp mode. Then it turned up misfire on Cyl 4.

The coil looked fine on initial inspection, but then i discovered a tinnnnny chip-away at the bottom of the rubber boot. Replaced it and alls well.

+1

 

[ph001]

I would just change all 6 coil packs for what they cost. It might solve your problem...it might not! If not, remove the top DISA valve (the one that’s easy to access) and inspect the inlet manifold for excessive oil deposits. If so it is probably a ccv problem and this can certainly cause idling issues like you describe.

The other very simple test you could do to check the ccv is to remove the oil filler cap with the engine running and compare against this video I made. It’s N52 but I’m guessing should be similar...

https://youtu.be/VhcqVSkhIeA

 

[Robert63]

Hi many thanks for the reply and the advice, I have just run the engine up and removed the oil filler cap as you have illustrated on your video, I am not getting that air escaping noise that you have on yours , are there any conclusions that can be gained from this. Many thanks.

 

[colb]

That rush of air noise when the cap is lifted is the air rushing into the vacuum, if you don't hear that then your engine has a bad vacuum due to air getting in elsewhere, check the underside of the cap first to see condition of the seal, if thats ok then smoke test it to track the leak(s) in the system.

 

[ph001]

Yeh, it’s air going in, not coming out. I think a bad ccv valve could cause lack of vacuum too. Be nice if someone with a healthy M54 could try the test just to confirm the N52 isn’t radically different in this area??

 

[Jembo]

There was some throttle body repair I did on my old 3.0 - it changed the plastic one to stainless steel.... can’t for the life of me remember the parts name right now

Didn’t cost too much, simple DIY if you have a set of spanners / socket set

 

[ph001]

There was some throttle body repair I did on my old 3.0 - it changed the plastic one to stainless steel.... can’t for the life of me remember the parts name right now

Didn’t cost too much, simple DIY if you have a set of spanners / socket set

^^^Good shout.

 

[Robert63]

Many thanks for all the advice, latest update is as follows
1 I have had a test done on the car again with adelphi software and there are no errors present.
2 When the engine is revved hard quite a lot of what appears to be "black muck" comes out of the back of the exhaust, not sure if this is right.
3 I have observed the DISA valve in situ and can see the rod moving when the engine is revved.
4 I have observed the DISA valve in situ with the electrical plug unplugged, obviously the rod doesn't move with it unplugged, however the engine behaves exactly the same with the valve unplugged.
Is all of this pointing to a faulty DISA valve or something else. Not quite sure where I am right now.

 

[enuff_zed]

Have you tried the coils yet?

It is conceivable that the 'black muck' is due to unburnt fuel as the misfire means not every cylinder full of mixture is being ignited.

 

[Rockhopper]

The black stuff you are seeing is probably just water and soot thats collected in the exhaust.
I'm not familiar with what the BMW ECU is capable of but many cars can detect misfires on individual cylinders.
General misfires are detected by tiny variations in the reading from the crankshaft position sensor.
If you are not getting an error code logged or the check engine light come on whilst its misfiring then I wonder if you have an ECU fault?

 

[ph001]

The op has no vacuum in the crankcase and black soot coming out of exhaust. Has bad ccv written all over it in my book. Surprised no M54 owners have stepped up to help and check if their car behaves same as in Youtube video.

 

[Robert63]

Hi Many thanks for all the tips . I have replaced the coils, also there are no error codes present. Perhaps my description of the problem is not quite accurate its not quite a mis fire more than a regular fluctuation with the engine revs up and down.

 

[craig3.2]

Mine was doing this recently too,and it was 3 bad coils. Renewed the 3,all fine now re no miss fire,poor/rough idle etc all gone.

If yours is still having similar issues, then,as ph001 said, symptoms also could be bad ccv?
That would be my next fix. Think they are relatively cheap,at circa £50,o.e BMW?

 

[Robert63]

Hi All many thanks for the tips so far, I have replaced the coils but the fault is still there. Perhaps my description of the problem is not quite accurate. Its not so much as a mis fire , more like a fluctuation in the engine revs up and down. Many Thanks

 

[Pete1726]

Coils all the way. Sorted mine out