I am in the process of swapping engines in an 89 325i and am having trouble getting the the engine to start. Before the swap, the old engine started fine so I know electrical system had no faults. After the swap, the new engine turns over but doesn't fire. I realize there are dozens of possibilities here but I have done some troubleshooting and this is what I have found:
1. Fuel pump doesn't run when relay is in place and engine is being turned over.
2. Fuel pump does run, though, when the relay is jumped out. Output is to spec.
3. Fuel pump relay is getting voltage from main relay so it can't be a wiring problem between them.
4. Have swapped out fuel pump relay for another and still won't run.
5. Engine still won't fire with relay jumped out and fuel pump running which leads me to believe there could also be an ignition problem.
Is this a Motronic DME problem maybe?
1. Fuel pump doesn't run when relay is in place and engine is being turned over.
2. Fuel pump does run, though, when the relay is jumped out. Output is to spec.
3. Fuel pump relay is getting voltage from main relay so it can't be a wiring problem between them.
4. Have swapped out fuel pump relay for another and still won't run.
5. Engine still won't fire with relay jumped out and fuel pump running which leads me to believe there could also be an ignition problem.
Is this a Motronic DME problem maybe?