Blowing fuse #11

[X_WizarD_X]

I keep blowing fuse #11 (Labeled-"Injection Electronics").
It does not happen immediately after starting the car. Usually after driving atleast a few miles it will blow the fuse. I have installed a new fuel pump and have changed the fuel pump relay thinking one of those may be bad. The voltage at the fuse (while car is running) only shows 11.8 volts while other circuits are showing around 12.2 volts. Anyone have any other idea at what may be causing it to blow. It can not be a dead short as it does not blow immediately. Does anyone know what other components are running through this circuit?

Thanks,
Dan


1991 318is M42

[Rocla]

I believe only fuelpump is behind that fuse.

[tonytony]

:stupid:

[DaN]

Just checked a diagram, only the fuel pump is on the circuit.
So I would check that you have a 7.5 amp fuse in there.
Check fuel pressure, maybe there is a restriction causing high current draw from the pump. Takes a bit to build up.
Maybe the pump is defective, what kind is it?

I'm curious why you have 11.8-12.2 v while running, do you have charging system problems as well?

[X_WizarD_X]

I'm curious why you have 11.8-12.2 v while running, do you have charging system problems as well?

I must have been getting a bad voltage reading earlier....I just checked again and was getting 13.8v on every circuit but the fuel pump circuit which was getting 13.2v....Very odd.....I just chaged out to a spare ECU and still the same problem. Also checked the voltage at the fuel pump and it shows 13.8v
And it is a new VDO pump...$230 worth...lol....Initially I also thought it might have been a bad pump, that is why I changed it out...

[Rocla]

I strongly think that if your problem is not in pump it's in the wire between fuse and and pump.

Not ecu, not relay or engine harness.

Edit: take of the + cable from pump and measure if pump side of fuse 11 is grounded, right after you've blown the the fuse.

[bimmer8604]

sounds like a high resistance problem somewhere in that circuit, i would check your grounds/connections.

kyle

[DaN]

High resistance= lower current. ohms law