F80 misfire

[Tymula_81]

Originally Posted by TopJimmy

Timing is off on 4 and 6. Gotta investigate further.

Why is Flex reading 90% ethanol?

I was on e90 doin a log for the tuner at that time

[Tech567]

Originally Posted by Tymula_81

So currently my car has a small misfire at idle but once I get passed 2k rpm the car runs fine. I changed the plugs,injectors,running compression test and tested the coils. Idk what else try. Back story is I was tuning my pi with f80 Paul and I kept getting a studder after 65k rpm. As i was changing the plugs i notice the old one had a small piece broke. I installed the new ones and still had the same problem. then he adjusted the pi. The car ran fine for a week while tuning then as I stopped at a Light I felt the misfire. I'm clueless right now any suggestions would be greatly appreciated.

Damn that piece can score a cylinder wall enough to not see on a major change with a compression tester but DME will pick it up.

[Wanted_M]

Originally Posted by Tymula_81

What cylinder

I'm guessing that's #6, that 105psi compression is heck of low for these motors as you might have damaged the piston/ring. What I do, is drive the car till engine is hot, come home, let it sit for half hour, remove everything and conduct test for best results. Rule of thumb is that all cylinder's variation should be 10% between the highest and lowest readings.
A new motor typically is 180-200psi, after several thousand beat down miles they hover around 145-160psi and that's what I'm used to. The best advice I can give from my past builds, is conduct a compression test prior to modifying so you have a baseline and conduct once/year or six months to check the health of motor.

[andrei.m4]

After replacing the timing and reseting the adaptations i solved my issues with missfire!!! 5k km tested and 0 issue!

[JAI///M3]

Originally Posted by andrei.m4

After replacing the timing and reseting the adaptations i solved my issues with missfire!!! 5k km tested and 0 issue!

What do you mean by replacing the timing?

[Tymula_81]

I figured it out. It was my flywheel

[Gotulukn]

Originally Posted by Tymula_81

I figured it out. It was my flywheel

How did you find that out? I'm having a misfiring issue with my 2015 m4, stage 2 catless. I had a valve cover gasket leak, so replaced that just that I figured its time for a spark plug change, since its been over 30k miles, but before that never had any misfires.

I had new BMW High power spark plugs, read that its better for flex fuel, gapped at 0.020, misfired at 4k under full throttle immediately. Codes for injector 5, and misfires happened Mechanic thought it was coils, I bought 6 new dinan coils, still misfired and installed a new injector, misfires were still there. I asked him to just changed the plugs to 97506, gapped at 0.022, misfires are gone and driving strong!

After 2 tanks of 93, and 3 tanks of full e85, the misfire is back at ~4k RPMS, but this time there are no codes.. even when i purposefully floor it to have it misfire, it just wont throw any codes, just sounds like my MHD antilag.

I guess I could look at my intercooler if its empty, or loose fittings for the intake etc...

[Gotulukn]

Originally Posted by andrei.m4

After replacing the timing and reseting the adaptations i solved my issues with missfire!!! 5k km tested and 0 issue!

How do you know it was a timing issue? My misfire issues still isnt resolved, I just changed my own plugs out today, installed new plugs again, and still wont go past 4k to 5k rpms with full throttle, no check engine light. half or even 60% throttle it revs fine.

[SWFL_M3]

I have been having the exact same issue in cylinder 4. Changed plugs coil packs injector spark plugs the whole 9. Tried all different mixtures of ethanol and no improvements. I’m left with a compression test and leak down I guess. Any insight from anyone or are more people experiencing this too?

[M Vier]

I have the same issue for the last few months.

Misfire at >6k rpm on sport plus and a good pedal push.

Spark plugs are relatively new. I was gonna change the coils, but after reading the thread, I may wait.

BMW AD couldn't figure it out. No codes.

M4, bone stock, well maintained, 100k miles.

Any idea? Thanks

[Tymula_81]

Mine was the flywheel. I had no codes but only shook at idle.3 springs broke in my flywheel

[Gotulukn]

Originally Posted by M Vier

I have the same issue for the last few months.

Misfire at >6k rpm on sport plus and a good pedal push.

Spark plugs are relatively new. I was gonna change the coils, but after reading the thread, I may wait.

BMW AD couldn't figure it out. No codes.

M4, bone stock, well maintained, 100k miles.

Any idea? Thanks

Hi and to everyone else in the thread too. I figured out my high rpm misfiring, it was difficult to figure out because there was no check engine light and all parts were new!

It was the damn DINAN COIL PACKS!! After having new plugs, new coils, new plugs again, new valve cover. I bought new delphi coil packs and my car is butter smooth again!