Fuel Pump Issues?

ruffdl · 08-16-2007, 08:42 AM

Six months ago my car (2000 528i) stalled on the hwy. A "so call" BMW tech diagnosed my car and determined it was the fuel pump. He replaced the fuel pump & fuel levelor and the car ran fine for about 4 months. Again on a different hwy, the car stalled again with the same symptons.. Just cut off no sputtering, no jerking, nothing.. I tried to start it and the engine would just spin.. I towed it home and left it . A week later I tried to start it again and it starts up on the first attempt.. I'm amazed. I proceed to drive it for a couple miles and it stalls again. It fails to restart.. I get it home again and call the "so call BMW tech" . He suggest that the fuel pump is gone again.. Again, he replaces the fuel pump and the car starts immediately and idles for 30 minutes or more. I again attempt to drive it again and again it stalls within 1 mi.. I lightly tap on top of the tank/fuel pump and the car restarts.. I get the car home again and it haven't started again since.. The so call BMW tech is no where to be found,, but he suggests that it sounds like the fuel pump relay switch. He said it was located in the trunk just above the battery. My question.. There are 3 square fuses/switches attached to the wire assembly in the trunk. 2 light green and 1 dark green.. Does any of these affect the ignition or fuel flow or would they cause the intermitting problems I'm having? Also,, I understand no one can successfully diagnose this over the internet, but I was curious to if anyone has ever experienced anything like this.. And finally, if anyone could recommend anything else to check.. Thanks in advance for your support.. This is my 3rd BMW over the past 10 years and this car has given me the most problems I've had out of any. I have over 170K miles.
Dennis

Jeron · Jeron's Garage

The relay is possibility but I don't know the location. The Bentley repair guide will show the location of the relay. Or maybe someone who has a manual will look it up for you.

Sometimes tapping on the relay will help it trip.

I would have replaced the fuel filter with the pump. I would also replace the fuel pressure regulator, assuming it isn't integrated into the fuel filter. Hopefully a clogged fuel filter hasn't damaged your new pump.

ruffdl · 08-16-2007, 10:46 AM

Thank you Jeron for your input & suggestions

grafhky52 · 08-18-2007, 06:45 AM

a clogged fuel filter will cause this situation also some thing to keep in mind is the 3-2 valve under the car. this also could cause your problem. the way to diag this problem is to measure fuel pressure starting at the rail and working you way back.

mrmistoff · 08-20-2007, 12:52 PM

We had same problem. Replaced the fuel pump & relay switch, the car would turn over but not start. Had it towed to dealer & they replaced the DME computer. It was costly, but the car is running like new again.