E36 M50 misfire

[thatdudeina36]

I cant figure out what's causing my e36 to misfire, I've replaced coil packs, injectors, cleaned out icv and replaced icv hoses, new crank position sensor, fuel filter, fuel pump, the car will shake violently back and fourth as it misfires and aswell as idle jumping all over the place, the car will sometimes rev up high and try to push past the brakes, whenever it stalls out the battery light comes on before any other lights do. I didn't replace the intake manifold gasket as they still looked good, I don't know what to do at this point or what could be wrong

[shogun]

moved to E36 forum

[E36 Em Tree]

Did you recently tune your car or change out your MAF? Possibly with the wrong one?

Also what were the recent events leading up to said problem? You check your spark plugs?

[thatdudeina36]

its a completely stock car, tried changing the maf sensor with another i had and no difference, it really starts to misfire even worse after accelerating hard but under city driving conditions it rarely does it. plugs only have 8k miles on them, and the misfire had just randomly happened it appeared and never left, the rpms drop and raise like crazy while driving aswell sometimes the engine will try to stall, its a auto aswell

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also i changed out the valve cover gasket so i have no oil in my spark plug holes or else where

[E36 Em Tree]

Have you checked the plugs recently to make sure the tips didn't break off? That could cause misfires

[thatdudeina36]

ive checked them and theyre fine but they were soaked in gas last time i checked them

[Ghost129er]

Sounds like a shoddy sensor or vacuum leak. Try disconnecting either one of the main sensors, whilst keeping the other connected (Eg, disconnect crank, leave cam connected/disconnect crank, leave cam connected). I had a similar issue turns out a faulty sensor was giving a shit input and causing the engine to miss and choke up like crap. Another issue I had with a crappy misfire/idle was the pipe to the ICV had blown off the joint due to a backfire in the intake and caused a massive vacuum leak which also affected the brakes.

The E36/M50 has the ability to run on a failsafe map with either one of the crank or cam sensors connected whilst having the other disconnected. Try it and let me know if it you find which sensor is causing the poor running condition.

PS - note that disconnecting the crank will mean you'd have to spin the key for a while to get it to start but worth a shot to diagnose and find what's wrong.

[thatdudeina36]

Sorry for not responding havent had the time to work on the car, I just tried with the cam position sensor disconnected, car ran like garbage then died, reconnected cam sensor now it only cranks and tries to start but then dies. possible crank sensor? already replaced the cam sensor 2 months ago

[Eric93se]

Measure the voltage to rule out an overcharging alt.

Early e36's charge at 13.8v

[JDStrickland]

I cant figure out what's causing my e36 to misfire, I've replaced coil packs, injectors, cleaned out icv and replaced icv hoses, new crank position sensor, fuel filter, fuel pump, the car will shake violently back and fourth as it misfires and aswell as idle jumping all over the place, the car will sometimes rev up high and try to push past the brakes, whenever it stalls out the battery light comes on before any other lights do. I didn't replace the intake manifold gasket as they still looked good, I don't know what to do at this point or what could be wrong

The battery light comes on when the engine is not running but the key is set to Position 2 (RUN). The battery light is not part of the symptom set.

I'm confused, you did not replace the intake manifold gasket because it looked good? If it looked good then it was destroyed and you need to replace it. The gasket does not tolerate being taken out and then put back in. If you had the intake manifold off, then you need a new gasket.

[thatdudeina36]

Fixed, Turned out to be the crank sensor

[ohgodohfucc]

I cant figure out what's causing my e36 to misfire, I've replaced coil packs, injectors, cleaned out icv and replaced icv hoses, new crank position sensor, fuel filter, fuel pump, the car will shake violently back and fourth as it misfires and aswell as idle jumping all over the place, the car will sometimes rev up high and try to push past the brakes, whenever it stalls out the battery light comes on before any other lights do. I didn't replace the intake manifold gasket as they still looked good, I don't know what to do at this point or what could be wrong

mine did the same, try grounding the DME case to the chassis, that fixed it for mine, a good test to see if this is the issue is to try and start the car with the DME outside of its compartment (still plugged in), and with a wooden piece separating it from the chassis, or a towel below it. If it just cranks but wont start your DME case needs to be grounded, dont ask me why the fuck it works, it just does. Now i have an alligator clip on my DME tray that i clip to the bracket and to the case to ground it inside the chamber.

Otherwise you have a vacuum leak maybe