Intermittant fuel rail pressurizes to 20 or 40 psi

[guyd_15]

The Mini has left me stranded a couple times now...

Turn the key, fuel rail pressurizes to 60 psi most of the time...

However, it has shut off a couple times while driving and also has had a no start condition intermittantly. When it cuts off or won't start I check the fuel pressure gauge it reads 0, 20 or 40 psi.

When I supply the pump with 12 volts from the battery (jumping directly to the green and black power supply wire), fuel pressure always rises to 60 psi.

I removed the fuel pump relay and energized it and checked continuity between the fuel pump supply poles, near 0 ohms resistance. Thought it might be the fuel filter, so I replaced it, no change.

Any thoughts...it's my daily driver and I need to get to work tomorrow!!!

Thanks,
Guy

[guyd_15]

bump.....

[mo' parts]

sounds like the fuel pump may be on its way out, or the check valve in the pump.
power up the pump by jumping power to the + side of the coil and pinch off the return line, it should peg your gauge.
you can also check the voltage at the pump connector to make sure your getting a solid 12+ volts. to check the check valve/leaky injectors or other, prime the pump take the gauge reading and see how long it will hold press. it should hold for a good while before bleeding down.
cycling the ign. a few time to get it to pressurize properly is also another sign of a failing pump.
hope it helps

[turbovanman²]

Adam pretty well has it nailed, it really sounds like the pump is going out. Check voltage at the pump and this will confirm it.