fuel pump - voltage going through fuse - 318i m40

[Headlock]

chaps - need some help - got a problem that I think may be down to fuel (or lack of)

checking voltages everywhere, but not getting 12 volts across the fuel pump fuse when trying to start the car - should it be 12v - or something lower?

does anyone know - or is anyone able to check with a voltmeter



also - does anyone know which relay is the fuel pump relay - think it is one of the ones that are outside of the fuse box - along the bulkhead, but not sure which one it is - there are slots for three, but I only have two in and can't find out what these two are for...

thanks
Steve

[Jackle]

I guess it'll be the same as my 325i, the middle one is the fuel pump relay, the one on the left (smaller than the others) is the DME relay, and the one that's missing will be for the O2 sensor (but if you haven't got an O2 sensor like me you don't need it anyway).

HTH

[Turbo-Brown]

Fairly sure it should be 12v across the pump terminals.

Not sure you can check the drop across the fuse, uness you're checking from the pump fuse to earth?

[Brianmoooore]

Won't be 12V anywhere when the starter motor is engaged. The starting current piulls down the battery voltage.
Check the voltage from the battery + terminal to the green/purple wire at the fuel pump, and from the fuel pump brown wire to the car body. These two added together will give you the total voltage drop.