M42 Fuel issues/ goes from 30 to 0PSI at WOT

[bmwman91]

Yeah, sounds like the pump since it ran fine up until the old one died and you replaced it. 40-45 PSI is normal for the M42 fuel system. If replacing the pump does not fix this, try a new fuel filter since they can get plugged.

Oh and yeah, the valve cover bolt holes are notorious for stripping. I had heli-coils in every one on both of my M42's.

[broach328]

injector. if the pressure was 0 psi but still running, then there must still be fuel flowing. But if an injector is sticking and bleeding all the pressure out under high flow but the engine remains running(although poorly), then that must mean the pump is still flowing normally and thats why the engine isnt shutting off entirely. If it dropped to 0 psi due to a pump issue, that would indicate total inoperation of the pump and the engine wouldnt run at all.

[Bimmian89]

http://www.youtube.com/watch?v=NcaD2oRjb4s

Car is running and has no fuel pressure, you can see the clear tubing. The car started and the fuel was about 10 inches above the T valve and stayed there until I revved the car a tad, but still had no pressure..

[Bimmian89]

AHHH, Finally its FIXED!! It was the power connector to the fuel pump was busted, so it would not stay on the prongs. The "fuel cut" i was experiencing was the connector going from making contact to not and would kill the pump and come back on. Wow am I glad thats fixed now to find a new plug somewhere. Thanks to everyone for the input!!

[oldmann]

Good deal.

We all made you look at a "good" part.

Easy fix to a difficult problem

[Bimmian89]

. That's the evil little plug!

[broach328]

the question now is how the fvk did that happen?

[Bimmian89]

Lol that's damn good question maine.. I'd say just 22 years and 165k.. Lot of time and miles. But the clip got broken somehow like changing the pump out, and just gradually worked itself apart.

[oldmann]

Find some small zip ties to wrap the plug with, My plug was opened up that same way. Then use one more to wrap around the receptacle too.

[Bimmian89]

Find some small zip ties to wrap the plug with, My plug was opened up that same way. Then use one more to wrap around the receptacle too.

Alright, that's kinda what I had in mind just electrical tape and small zip ties

[Bimmian89]

Does anyone know where to find a pump connector ive been looking for about 2 hours now. I need to know if i can just cut it, and splice it. There is a brown wire and orange and green maybe.. I just wanna know which is power and ground. Thanks

[bmwman91]

I've had mine zip tied in place because of the same issue for years without issues.

[Bimmian89]

Yeah I tried that and its just to sporadic, its like one of those wires is shorting out or something. It will run great two seconds later same thing jiggle it or move it a tad runs good. Is there any way to cut it off and splice a new connector of some sort on there? Im assuming its just power and ground right? Solid wires?

[roguetoaster]

Yeah I tried that and its just to sporadic, its like one of those wires is shorting out or something. It will run great two seconds later same thing jiggle it or move it a tad runs good. Is there any way to cut it off and splice a new connector of some sort on there? Im assuming its just power and ground right? Solid wires?

If you have a junkyard near you that has BMWs you should be able to find that plug and splice wires. Alternately you might want to consider cracking it open a bit more and soldering the wires to the connectors if possible.

[broach328]

Yeah I tried that and its just to sporadic, its like one of those wires is shorting out or something. It will run great two seconds later same thing jiggle it or move it a tad runs good. Is there any way to cut it off and splice a new connector of some sort on there? Im assuming its just power and ground right? Solid wires?

Its probably like a middle aged hooker and the poles on the pump do not fit snuggly in the female connector anymore. Poor fuel pump :(