1996 BMW 328 fuel delivery

328is · Posted at Sat Jul 05, 2008 3:10 pm

Electrical problem
1996 BMW 328 6 cyl Two Wheel Drive Manual 100k miles
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my fuel pump only runs when power is applied directly from the battery. the relay is operating correctly. although the pump runs with the battery powering it and the fuel is pressurized at the fuel rail the car will still not start. i have good compression and good spark. Shouldn't the vehicle still be able to fire if i have power to the pump?

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Dr. Hagerty · Posted at Sat Jul 05, 2008 4:42 pm

The item you have overlooked is if the fuel injectors are actually injecting fuel, check for an injector signal and let us know.

328is · Posted at Wed Jul 09, 2008 6:38 am

How do i go about checking for an injector signal? I don't think I have one, so what would my next step be after confirming this?

Dr. Hagerty · Posted at Wed Jul 09, 2008 5:26 pm

If there is spark then a bit of carb cleaner sprayed into the intake will get the engine started. The fuel injector signal or lack there of, can be determined by removing the electrical connectors at the injectors and installing a small light bulb called a "noid" light and watch to see if it lights up indicating fuel being injected. It is possible the computer that controls spark and fuel is faulty. I recommend seeking out a local BMW shop for the diagnostics.