Cylinder 4 and 5 misfire? My 98' M3

///M3* · #1 (**permalink**) 03-21-2007, 05:28 PM

Hey guys....I haven't posted much on here untill today so I feel like an ass, but this is whats happening with my beemer here and I appreciate any help.

So im out for a Sunday cruise and im just cruisin along on the hwy out here and I drop into 3rd then hit 4th then finaly 5th and im crusin about 120 or so then I pull of at my friends house and I notice my car is not sounding like it usually sounds and soon enough my check engine light comes on. So I have it towed to my mechanic and cylinder 4 and 5 have a misfire. I spoke with him and so far he has not found anything that just sticks out and says here I am fix me. He mentioned that one of the cylinders has a psi of 56=0. He has used a bore scope and did not see anything that just stuck out at him. He is going to drop the oil pan and check to see if he can find anything in that area or anything. My engine has 99,000 miles on it and has been babied. Less than a month ago I put a new timing chain in just to keep things up to date. He's a real nice guy that works on it and the shops called German Service LTD here in Oregon. I trust his work, but is there anything in the timing chain area that he could have had wrong and the problem I am having now is a result of that? I know it's a long story! Anyone here have any hope or answers for me or is this going to be 4k on a rebuild? Your feed back is appreciated, thanks!

reavisM3 · #2 (**permalink**) 03-21-2007, 08:06 PM

Usually if it's something in the timing it will effect all the cylinders. I would start with the basics. Try swapping the spark plugs, coils and injectors around to different cylinders and see if the misfires follow. If you don't have any results then you may have to tear into the engine. A cylinder with 56psi is pretty low but I wouldn't go tearing into an engine without checking the above mentioned stuff first.

Also what happens if you clear the faults? Does it run better? It may have just been sporadic faults caused by bad gas or something like that.

///M3* · #3 (**permalink**) 03-22-2007, 05:46 PM

When my friend used his peak tool to reset it the problem seemed to get better for a second and then the engine light and prob came right back 5 sec later...so maybe im just losin it and it really never sounded better, haha. I'll keep an update, but so far I have not heard anything back from my mechanic=( Thanks

BadGTho · #4 (**permalink**) 03-23-2007, 10:25 AM

you might have a problem with a coil pack harness, ground strap or plug connector...

and just thought i'd add that there is no way to manually time that car.

///M3* · #5 (**permalink**) 03-23-2007, 11:12 AM

So it is all electronically timed in this vehicle? I'm on a learning course with this car so bare with me...To check the coil pack harness, ground strap or plug connector...ext that would mean opening up the engine and divin' in correct? If I have my engine open once I would like to do a few things while im at it cause it just makes sense but let me know. I have 99k on my engine and trans. and would like to install a AA turbo in a short while. Not trying to get ahead of myself, but would you recommend forged pistons and rods while I have the engine open. Or is all that just not necessary? New Cams? Anything else you would recommend? Thank you for your help

goob_os101 · #6 (**permalink**) 03-23-2007, 12:33 PM

I had the same probs and it turned out to be a bad exhaust cam...FYI I did buy a head and had it taken to a machine shop to have them check the valves and to refresh it. I do not need it now and I can sell it to you if you want to built up a head or just to have as a spare.

///M3* · #7 (**permalink**) 03-24-2007, 11:24 AM

The car is not in my control at the moment........My mechanic has had it a week this money. I mentioned all the above suggestions to him...I have heard no answer from him yet, but thank you for help and ill keep an update

Paradigm_Guy · #8 (**permalink**) 03-24-2007, 01:19 PM

Quote:

Originally Posted by ///M3*

So it is all electronically timed in this vehicle? I'm on a learning course with this car so bare with me...To check the coil pack harness, ground strap or plug connector...ext that would mean opening up the engine and divin' in correct? If I have my engine open once I would like to do a few things while im at it cause it just makes sense but let me know. I have 99k on my engine and trans. and would like to install a AA turbo in a short while. Not trying to get ahead of myself, but would you recommend forged pistons and rods while I have the engine open. Or is all that just not necessary? New Cams? Anything else you would recommend? Thank you for your help

Just remove the plastic piece that covers the passenger side of the engine (where the oil cap is). You'll see the coils there. The socket's are all 10mm, and you'll want an extension for the ratchet. Would take 10 minutes max to switch around the coils.

Has your mechanic done a compression test?

///M3* · #9 (**permalink**) 03-24-2007, 04:48 PM

Quote:

Originally Posted by Paradigm_Guy

Just remove the plastic piece that covers the passenger side of the engine (where the oil cap is). You'll see the coils there. The socket's are all 10mm, and you'll want an extension for the ratchet. Would take 10 minutes max to switch around the coils.

Has your mechanic done a compression test?

He said cylinder 4 has a psi of 56.....What would you say based on that low of a psi? Any suggestions?

Paradigm_Guy · #10 (**permalink**) 03-24-2007, 06:47 PM

Quote:

Originally Posted by ///M3*

He said cylinder 4 has a psi of 56.....What would you say based on that low of a psi? Any suggestions?

Sounds like it may be a bad exhaust valve. A leak down test can confirm it.

baesoju · #11 (**permalink**) 03-25-2007, 05:45 PM

Could there be any issues resulting from some highway driving ?

BadGTho · #12 (**permalink**) 03-26-2007, 05:38 AM

Quote:

Originally Posted by ///M3*

So it is all electronically timed in this vehicle? I'm on a learning course with this car so bare with me...To check the coil pack harness, ground strap or plug connector...ext that would mean opening up the engine and divin' in correct?

incorrect. remove the plastic "M power" cover.. and its all right there.

BadGTho · #13 (**permalink**) 03-26-2007, 05:39 AM

Quote:

Originally Posted by baesoju

Could there be any issues resulting from some highway driving ?

NO.

///M3* · #14 (**permalink**) 03-26-2007, 10:24 AM

sweet deal......im gonna mention a leak down test to my mechanic and have him check the coil pack harness, ground strap or plug connector as well.....im kinda having to push him along here and it makes me wonder why he has had it a week and no answer. Thanks for the help guys

Paradigm_Guy · #15 (**permalink**) 03-26-2007, 11:39 AM

Might want to try a different mechanic.