Bmw E90 320i engine N46B20BA misfire issues

[bonecrusher]

Hello Guys.

I am working on this vehicle.The car had misfire fault.I had cleared the fault codes(the misfire went away) and then fitted in 2 good coils that I had in stock to cylinders 3 and 4.Took it for a drive and re-read the fault codes. and this is what comes up

1. 2C24 O2 SENSOR (BANK 1, SENSOR 1 AND BANK 2, SENSOR 1) INTERCHANGED

2. 29CC COMBUSTION FAILURE ,
MULTIPLE CYLINDERS DETECTED

3. 29D0 COMBUSTION FAILURE : CYLINDER 4 DETECTED

4. 29CD COMBUSTION FAILURE : CYLINDER 1 DETECTED

5. 29CE COMBUSTION FAILURE : CYLINDER 2 DETECTED


6. 29CF COMBUSTION FAILURE : CYLINDER 3 DETECTED

7. 2E27 IGNITION COIL, CYLINDER 4 FAULTY

Thanks guys

[ori793]

this might not be coil problem but spark plugs, did you replace spark plugs as well?
whats is the mileage? these spark plugs tend to fail after 100K km from my experience.

you have to fit exact same coil and no other that "look the same" on this car.

[bonecrusher]

spark plugs are new

[eliasole]

Look intake for leaking and loose under pressure.

[eliasole]

or the maf.....

[bonecrusher]

I will fit in a new maf and see what happens.

[ori793]

what's the reading of current MAF on data?

[genius76]

on oldest 532 and similar be problems with pressure if you checked all electronics and 100% lambda sensor are correct - check pressure in cylinders

[mtechno]

I have known this engine to jump timing chain if it backfires, check valve timing has not altered as a result of missfire also check engine breather system pipes are clear & no air leaks have occurred.

[easytech]

Timing chain is indeed a trouble maker but when worn or jumped usually ecu throws also cam sensor fault.
Check the crankcase breather below the inlet manifold, simple test is to open the oil filler cap when engine running, if it nearly stalls the breather valve unit is broken.

[bonecrusher]

I have checked the crank breather it is ok. I have installed 2x new original oxygen sensors before cat, 4 x new coils and plugs and yet I still have the same faults.

[smokey08]

Looks like the pre cat oxygen sensor connectors are connected wrong. Swap the connectors with each other and try it again. I suspect they are lean misfires where the sensors are adjusting the wrong cylinders.

[the_riddler]

Agree with above
sounds like 1 off the faults is wrongly connected sensors.

happens alot on head work when tech does not lable connectors, whilst removing

but not seen those other faults at same time before....
but hey we learn new stuff by the day...

[bonecrusher]

Thanks for the tip, will update soon as it is fixed

[bonecrusher]

never got to fix this car. The customer and I were tired of putting money into the car. I advised him to take it to someone with more knowledge