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Marty, ASE Certified Technician
Category: Car
Satisfied Customers: 54022
Experience:  ASE & Bosch Certified Master Tech. Over 30 years experience.
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I have a 1988 bmw 635 csi the car will run for an hour then

Customer Question

I have a 1988 bmw 635 csi
the car will run for an hour then it shuts off creating pressure at the fuel rail, i can pull off the main fuel line relive the pressure then it will re-start. I have changed the fuel pump,
fuel injectors,pressure regulator, coil , cap , rotor, computer, timing position censor,idle control,unit, throttle body.
now i changed the in tank fuel pump. the pump connector was shorting out on the inspection plate. all is new but there is no power to the pump. What control the power to the in tank pump. PLEASE HELP.
Submitted: 4 years ago.
Category: Car
Expert:  Marty replied 4 years ago.

eurotec :

Hi, power to the in tank pump comes from the fuel pump relay through fuse #11. The fuse powers both the main fuel pump and the in tank fuel pump. If you have power to the main pump but no power to the in tank pump you must have a fault in the wiring between the pump and the fuse.

eurotec :

Full Size Image

eurotec :

Click on the wiring diagram above.

eurotec :

Let me know if you need anything else.

JACUSTOMER-87gx58x2- :

Thank You , would a faulty in tank pump explain the car shutting off after running for lets say an hour? This is my issue that i cannot solve

eurotec :

Hi, I think it's possible that a faulty in tank pump could eventually starve the main pump and create a problem. Ideally you should connect a fuel pressure gauge to the system to monitor the fuel pressure when the car dies and won't start.

JACUSTOMER-87gx58x2- : Thank you
eurotec : You're quite welcome. Let me know if you need anything else. If you would please take a moment to rate my service I would appreciate it.