RomRaider

Hi, I'm Currently working on a E61 523i With an MSD80 ECU,

I have got the following problem, The car keeps misfiring on Cyl4, With that misfire the injection is cut off.
The misfire only occurs when the car is idling with a warm engine, misfire allways comes up around 660/700 rpm's
when driving the car evrything is fine, not one single misfire untill the car is stationairy again

I have changed the injectors, spark plugs, coils, And Maf sensor Without result.. (i have coded the new injectors the right way)

Does anyone maybe have a clue whats going on here ?

Or Does anyone maybe know the MSD80 system ? When i Raise the idle rpm's to lets say 800rpm.. than no misfire occurs, But this can only be done briefly whith inpa. When i unplug and start the car again the rpm is again at 660

I have got the original full flash from the car, But i can't find the Idle Rpm map. Also i can't verify checksums

Hope maybe someone at this forum can help me

PS: Ori File added

Gr, Richard

Verify that there is no air leakage around Cyl4 injector or intake runner.
You may spray carb cleaner around. Idling engine will suddenly change RPM if there is some leakage.

The are no vacuum leaks.. i wish it was that simple

You may try to reconnect and switchover cyl3 and cyl4 wiring connectors to verify the ecu and wiring.
Provided this is not a direct injection system.
Subaru EZ30\EZ36 is prone to ecu failure of a similar way - injector driver is overheated.

do you mean change only the wiring ? or change the injectors, if i only switch the wiring from cil 3 to 4 it will not run correctly i guess ?

I did the injector changes many times to make sure the fault is not in the injectors, Coded them all with inpa with the right values that are on the injector, The car is still misfiring on cil 4 when stationairy

Do you maybe have a damos file or map pack for this engine ? If i can manage to raise the stationairy rpm the fault won't come back.

gr richard