Electrical troubleshooting thread. I'm stumped.
Before I start in, please accept my thanks for even reading and helping. It means a lot to me. My end of the bargain is to be quick to answer in a complete way, researching and investigating as much as I can.
'91 318is with a swapped M50NV and g240
Automatic harness
m20 starter/flywheel
I'm at the point of trying to crank my motor but I am not sure what piece is missing to get it to that point. If I try to crank the car, I get nothing. No turning over, no fuel pump prime, no starter click. With the key in the on position, I get all lights at the bottom of the gauge cluster on, and they dim when I turn the key to start it. I can visibly see my black/yellow wire move when I turn the key. Also, when the key is in the on position, I can hear a slight hum coming from the starter, which I am thinking is fishy. But, before I take the intake back off for the eleventy-millionth time, I wanted to check here.
Troubleshooting completed already:
- Fuel pump primes when supplied external power
- Continuity light shows power at the B+
- Continuity light shows power at the big starter terminal/wire
- Continuity light shows power at the relays on red wires full time
- Continuity light shows power at the relays on white/red wires on "on" position
- Fully charged group 48 battery and tested with another battery to make sure
- Ground wires present on both drivers and passengers side, and have jumped ground positions to other sources to verify.
Known issues:
- Oil level sensor wires not hooked up
- One loom of automatic wires still present in the harness, yet to be deleted
- SRS wire not jumped
- Tach coding plug not installed yet
Here's some photos of what I'm working with. Verbal beratements accepted, but I'm shooting for a running car before I patch it all up nicely.




Any help or direction is appreciated. Thanks!
Before I start in, please accept my thanks for even reading and helping. It means a lot to me. My end of the bargain is to be quick to answer in a complete way, researching and investigating as much as I can.
'91 318is with a swapped M50NV and g240
Automatic harness
m20 starter/flywheel
I'm at the point of trying to crank my motor but I am not sure what piece is missing to get it to that point. If I try to crank the car, I get nothing. No turning over, no fuel pump prime, no starter click. With the key in the on position, I get all lights at the bottom of the gauge cluster on, and they dim when I turn the key to start it. I can visibly see my black/yellow wire move when I turn the key. Also, when the key is in the on position, I can hear a slight hum coming from the starter, which I am thinking is fishy. But, before I take the intake back off for the eleventy-millionth time, I wanted to check here.
Troubleshooting completed already:
- Fuel pump primes when supplied external power
- Continuity light shows power at the B+
- Continuity light shows power at the big starter terminal/wire
- Continuity light shows power at the relays on red wires full time
- Continuity light shows power at the relays on white/red wires on "on" position
- Fully charged group 48 battery and tested with another battery to make sure
- Ground wires present on both drivers and passengers side, and have jumped ground positions to other sources to verify.
Known issues:
- Oil level sensor wires not hooked up
- One loom of automatic wires still present in the harness, yet to be deleted
- SRS wire not jumped
- Tach coding plug not installed yet
Here's some photos of what I'm working with. Verbal beratements accepted, but I'm shooting for a running car before I patch it all up nicely.




Any help or direction is appreciated. Thanks!
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