Thread: Fuel pump problem....new pump, power to pump, pump doesnt work

So guys, I have a 2000 P11, it tries to turn over and crank, but doesnt. I changed the cap and rotor for the hell of it.

So it came down to fuel, pulled the fuel filter, no gas came out when trying to start or anything.

So anyway, I checked the current to the pump, it has power, but the pump wouldnt turn on, so I changed the pump to a Walbro 255, and put everything back and when I put the key on start the pump wont turn on, I also changed the fuel pump relays with new ones and nothing, I checked the fuel pump fuse and its good and getting power. The only fuse that I wasnt getting a reading in which I replaced was the starter motor, but it works so no biggie.

What can it be? And how can I diagnose this problem further from here? Is this ECU related? Helllp!

If there is voltage at the pump terminals and the pump still doesn't work it's a bad pump. Not sure what else there is to say.

Not necessarily, ive looked this up, this has happened to other people before. Im trying to think what else it could be without having to run a power wire from the battery to the pump wires

I guess what I meant so say was that if there is +12v between the pump terminals, the problem lies in the fuel pump. No?

yes



if good power at the pump harnes then yep , bad pump....


is the P11 pump controlled by the ecu?

I unfortunately do not have a voltage meter, just a test light.



The P11's is controlled by the ECU. For example if you copy the key (to a non chip key or not programmed chipped key) the car does a fuel cut off when the non programmed or copied key is inserted, all via the ECU. I tried my other keys and none work, I hope its not ignition related.

The car has been sitting for about 3 weeks, do you guys think maybe the battery has enough power to attempt to crank but not enough to power the fuel pump? When I tested with the light, one of the positive terminals lit up the tester light really bright, the other was very faint. (think the positive plug has two connectors, one of them was very faint).

Oh god... The ECU has an immobilizer? That could be the culprit right there (I wouldn't rule it out).

You say your test light shows voltage on both positive terminals for the fuel pump but one is faint and the other is not? I don't know the P11 wiring, but my guess would be the wire that gave you the bright light is the fuel pump +12v source. I'm guessing the other wire that had less voltage comes from the immobilizer circuit in the ECU and acts as a low voltage switch for the fuel pump circuit. Since you're getting some voltage there is sounds like that's working.

Then again, I could be wrong and the ECU could just not ground out the fuel pump relay to control the pump during immobilization. It seems I'm well out of ideas. Sorry. =(

Edit: Oh yah, it's time you bought a digital multimeter. I think I bought mine for $15 some five years ago and it's served me well. Just feed it a battery every couple of years.

+1..

I used Fluke's at work all the time, but found the $15 ones from the auto parts store to work just fine for what we're doing. we don't need to have 99.99999999% accuracy.. 99.5% accuracy is just fine....

i left mine out in the rain though.. argh

hopefully you get it figured out man. oh and the ve is still going strong.

Very true, im going to Spain in 3 days, I dont have time to diagnose, I just dont want my car to get booted and towed so im looking for any alternative. Ive never had an issue with this car which is why this pisses me off!!! I might take a look at the ECU, it might be wet or something, the car has been in 2 major accidents all in the front and its been fixed (I went the cheapo route of fixing it and I mean I dont have any wheel well liners and such, everything else was done perfectly) so I wonder if any water got to the ECU, this all happened after the typhoons we had in NYC/NJ 2 weeks ago.



Great to hear man, im glad you stuck with the community. Ill return someday, but with a GTiR.