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pcross
11-16-2008, 06:43 PM
My 1995 525i ran like a charm yesterday. This morning, It would turn over, but would not start. I pulled and checked all the plugs - Good. Checked for hot spark - good. Checked the fuel pump fuse and relay - good. checked for voltage at the fuel pump - 12.3v good. Then, I pulled the fuel pump and put an independent 12 volts to the pump terminals - the pump ran. So...I'm getting a hot spark and voltage to the fuel pump which ran on the bench. Does anyone have any suggestions? I'm stuck.

pcross
11-16-2008, 07:57 PM
I've had an afterthought...Just because the pump runs when 12v is applied on the bench does not necessarily mean that it will put out sufficient pressure in the tank, correct? It could be spinning but not pumping, right?

whiskychaser
11-17-2008, 10:50 AM
I've had an afterthought...Just because the pump runs when 12v is applied on the bench does not necessarily mean that it will put out sufficient pressure in the tank, correct? It could be spinning but not pumping, right?

It may run ok on a bench but the fuel system runs at about 50 psi so the pump may be a bit lazy. Best way to check is with a pressure gauge. Did you try jumpering the relay and checking that fuel is making it to the rail?

pcross
11-17-2008, 07:11 PM
Yes. I jumpered the relay. Fuel was dribbling from the rail. Bad fuel pump. Ordered another today. Thanks much, Whiskeychaser.