Fuel pump issues.

[japmaxse]

Well I'm trying to help a friend out with his P5. We disconnected the outgoing line from the pump to see if there was any fuel coming out but nothing. It primes itself and receives 12v at the pump but no fuel. lol

Half tank full, I can here the pump whine when trying to crank but man there isn't any fuel coming out of the pump.

The pump is brand new along with filter, injectors rail FPR. With carb cleaner it starts right up so I know it's not electrical as far as ignition goes.

So what in the world is wrong with his car?

[japmaxse]

Now it's getting fuel to the inj weird. But it still wont fire up. maybe bad inj going to see if there working properly.
If you have any suggestions chime in.

[P-Funk!]

Bad pump or it is not a direct replacement.

Try another. Check the grounds as well.

[japmaxse]

Just a quick update. I checked the power at the pump while cranking it's receiving 11.9-12.0 volts. Which is about right. I also hooked up a fuel pressure gauge since now it's finally getting fuel to the rail but there's no pressure. I took off the FPR and theres barely any fuel getting to that side, it just trickles out.

Would there be any other reason why the pump is weak on supplying proper fuel pressure? Is the voltage supposed to be higher? Or is the new pump still bad?

[i12drivemyMP5]

Not a pinched or crimped metal fuel line anywhere?

[japmaxse]

Nope we checked it thoroughly. We might try another pump. I've never seen a pump do this, either they work or they don't but never half assed.

What I need to do is see a good pump flow and compare.

[grindMARC]

Are you sure you got the grommet and little plastic washer thing on the fuel pump properly?

If its a Denso fuel pump the odds of it being bad are very low. The other brand (can't think of the name of it) made for the P5 are not nearly as reliable as Denso's out of the box. This according to my buddy that owns an auto parts store. I suspected a new Denso of being bad just recently. Turns out it was my bad install and he was right. But, my problem was that the pump wasn't holding prime, not that it wouldn't start.

Did you check the fuel pressure at the fuel damper too? And then at the regulator? The service manual has step by step diagnostics for this sort of problem. Having a fuel pressure gauge will have it narrowed down in no time. Send me a PM with your email addy and I'll pass along the pages from the service manual if you don't have it.

[bazooka joe]

i have a spare walbro if you wanna borrow it?

[japmaxse]

Hey guys it finally started up thank God. Now we hate BOSCH fuel pumps because it was brand new and didn't even work properly. We went to the scrap yard for a pump costing only $30 with warranty and it worked like a charm.

Thanks guys for the help.

The P5 is back alive.