M50NV: injectors not firing? Not starting

[tazer]

There are a few things worth checking-

-CPS could be bad-
-Is the harmonic balancer (crank pulley) the one that came with the motor? the M50NV and M50TU are different and can cause a no start for correlation.
-Im not positive on the M50NV but there is a grounding wire on the M50TU that runs out to the front side of the vanos unit. Someone mentioned this is a ground for the injecotrs
-Check your ground from engine to the chassis once more to make sure there isnt corrosion between the contacts.
-Final thing, check check and re check your wiring from the M50 harness to the E30 body harness. Simple to do a continuity check to make sure whoever wired the adapter did the correct pin-out.

[Nick_S]

-CPS will replaced with another that is also tested well within spec
-Yes, harmonic balancer is stock to the motor, I'll double check it's installed correctly but IIRC it has a guide pin?
-Injector ground is secured and check for good grounding
-Will double check and re-wire wheel it to be sure
-Harness adapter from Nando. He seems to have made quite a few that work properly so I'm trusting this was done the same.

[dillon7]

I just had the same exact problem and it ended up being bad injectors. Pull out your injectors and bench test them to be sure that they will open.

[Nick_S]

I just had the same exact problem and it ended up being bad injectors. Pull out your injectors and bench test them to be sure that they will open.

Hadn't thought of that for some reason. I soaked them in Sea Foam over night but didn't bench test them. My idea was to get the car running first, then sort out any lingering issues. Hopefully they're not causing it to start in the first place.

Today I tried two new different DME's and nothing helped. Tried my other CPS which was again, supposedly good and no luck. Ordering new cam and crank sensors this week to eliminate that variable. Still cranks and seems to have spark (runs with carb cleaner sprayed in) but while cranking, we tested a positive on an injector harness and it wasn't seeing any sort of power during cranking. I couldn't imagine 3 different DME's being bad and since both CPS I had were used I'm realllllllllly hoping that's the issue. Otherwise it would seem to me it would have to be the harness adapter because that's the only other major component that has changed.