My M52 Runs Horrible, Stalls If I Apply Throttle, Rough Idle EDIT: Solved!

[KI4UJO]

I thought about adding this to the mystery connector thread, but I figured that it deserved its own.

My m52b28 came out of an e39. It ran perfectly - no misfires, rough idle, or any other issues (The car was an auto, and would not shift out of 1st). I pulled it, intending to drop it directly in. The only thing done to the motor while it was out (besides transferring the m50 flywheel, pressure plate, clutch and G250) was to replace the timing chains, tensioners, and guides (I found a broken guide and opted to replace all of it at once). The timing service was completed before changing the flywheel, using the correct timing blocks, flywheel pin, and cam advancement tool.

Currently, the motor is running on MS41.1 OBD2 management using an e36 auto harness, along with an m50 manifold, OBD1 valve cover & 1 year old coil packs (I am not running the oil separator). It is incapable of revving without stalling. Anything over 10-15% throttle will stall it. When restarting, I have to give it gas or it will not refire. I have been unable to find a vacuum leak, though I have not performed a smoke test.

Since I'm out of ideas at this point, I figured I'd let you guys take a shot at it. Here are the INPA screenshots:



























Any ideas? Also, I just noticed the battery voltage, however, I'm pretty sure the alternator is wired correctly (and was functional with the m50).

Any help is appreciated, I just want to drive my e30 again!

[328ijunkie]

Start with cyls 4/5 misfire. Water in spark plug holes?
Its pulling some fuel but i would eliminate misfires first and move on to fuel trims next. Who flashed ECU?

[KI4UJO]

There isn't any water in the plug holes (I had all of the plugs out a few days ago to do a compression test, simply to prove that the problem was electrical). For reference, the DME was flashed by Kassel Performance. I'll try swapping the coils & injectors later today and see if it makes any difference.

[328ijunkie]

Your air consumption at idle looks a smidge high. Kassel didnt delete Evap stuff on your ECU either. Try moving coils 4/5 to 1/2?

[KI4UJO]

I'll try it in a few hours when I get home.

[diesekte]

I had exactly your symptoms once. My issue ended up being that "turkey neck" hose attached to the ICV was fubar right before it connected to ICV kind of underneath it, so it was not at all visible without pulling the whole manifold. May be worth checking out if what dave suggested doesn't work.

[KI4UJO]

I switched coils 4/5 to 1/2. No change, misfire code is still on 4/5. Also, all of the ICV hoses are in place.

[Northern]

Assuming you're running an OBD1 fuel rail since you're getting a running losses error... are the tabs bent enough that injector 4/5 are actually plugged in? I had a cyl 1 misfire for that exact reason.

That tank valve and running losses error should've been flashed out by whoever you bought your tune from (although I guess some people keep the running losses valve)

[328ijunkie]

also whys your voltage so low?

[KI4UJO]

I don't know on that. It appears to be normal. On a side note, I think I have found (at least a major part) of the problem.I decided to change VANOS modules back to the one which came with the m52 (I had swapped it for the unit which I had rebuilt, but never actually seen operate). After this, the car ran the same, with one exception: an error code of "VANOS Jammed." Took the valve cover off to find that I had improperly timed the motor by a few degrees. I'll retime it tomorrow using the TIS procedure tomorrow and report back.

[KI4UJO]

Solved! My catalytic converter was plugged. I'm not quite sure how, as it was only a year old. At least I can move on with the build now.