BMW Repair Questions? Ask a Mechanic for Answers ASAP
Hi, welcome to Just Answer.
With the jumper in place...see if the engine runs. Also, how did you determine the old fuel pump was faulty?
Alright, you may have a bad computer main relay or the engine computer. The engine computer triggers the Main Relay, which in turn triggers the fuel pump relay. If the main relay is not the problem the engine computer might be. With the fuel pump jumpered, it should allow the engine to run. Switch out the Main Relay, if the engine still doesn't start...tap on the engine controller gently while someone cranks the engine and see if it fires than.
Main Relay Location.
The crankshaft sensor could be a possibility, but if you are not getting both spark and no trigger to the fuel pump relay, it further indicates a deeper problem. If you are getting good spark, than you can elliminate the CKP sensor. The engine computer is also in the "E" box with the fuel pump and main relay.
It doesn't mean that the engine computer is o.k., but it means that the ignition spark and engine compression is good. So either your problem still lies in just the fuel delivary or the fuel injection. Do you have access to a fuel pressure guage?
Well, that's difficult to interpret without a guage..it should shoot out. Did you replace the fuel filter? Are any of the hoses kinked? Did you install a NEW pump? Are you positive the fuel level is sufficient for the pump to pick up? You also need to be positive none of the lines at the pump are loose or cracked and sucking in air...if so that will reduce the pressure and flow.