M20 engine running on 3 cylinders :(

[Chuckcruzin1986]

Hello,

We rebuilt my 87 M20 engine and just started it. Number 2, 4 and 6 is not firing but is getting spark. Compression is nice and even. We pulled the plugs and they are new, clean and dry.

It seems odd to me that every other cylinder is firing. Ideas?

By the way, we put a 1990 ECU in it which is number 380 .... could this be the problem? We also tried an "E" computer.

Thanks,
Chuck

[Chuckcruzin1986]

found the problem, plugged injectors

[FadedGreyE30]

Did you get new injectors or clean your old ones?

[Gruelius]

broken wire in ecu harness bad ecu. check injector banks using multimeter and if that doesnt work try someone elses ecu.


also check fuses 10 20 21

[jlevie]

Those cylinders are injector bank 2 and all of them not firing suggests a fault in the firing cricuit for that bank. Run a continutity check from the DME connector to the injectors on those cylinders. If not a wiring problem it will be the DME.