944 Only Runs With Fuel Pump Disabled!

[eligunn]

I decided to start a new thread for this problem because I think the solution might not be related to anything electrical after all.

Basically what happens is the car runs super rich with the fuel pump enabled, but once I disconnect the pump it runs fine. It doesn't drive but it runs.

I googled this problem and found that another European car forum had this phenomenon listed as something people had experienced while trying to purge the fuel lines of gas by unplugging the relay or fuse. The car will run like this, but not have enough fuel to provide any torque.

What I found out with my car was that if I unplugged the fuse for the fuel pump( which I did to purge the system so I could disconnect the fuel rail) was that it ran fine and didn't stall out. where as before I couldn't get it to run at all or very poorly when it did run.

So my question is, what is it that would make a car run by sucking up it's own gas that would also make it not run with the electrical pumping of the gas enabled.

I have been trying to get this car to do something besides sputter and smoke for over a year now. This the first time I've had any positive result and that was by disabling a system that was supposed to be crucial to the running of the car.
My neighbor even came by while it was running and said it sounded great, and then I had to explain to him there was a demon inside the gas tank making it run.

I think what I need to do is just replace the damper and regulator.
I just want to know how this could happen. It's the weirdest thing I've ever seen a car do.

[krystar]

are the plugs wet fouled?

might injectors stuck open and it's just dumping fuel. that'd sort of explain how it's sucking fuel in and pretending it's a carb

[eligunn]

Yes I am thinking this is a possibility. Could the afm be telling the computer to send the maximum amount of fuel? I have tested the afm and it tested good.

I don't know for sure whether or not the injectors are staying open when the motor runs, but I don't think this is the case when it is not running because it seems to hold a bit of pressure while it sits.

[krystar]

unplug the injectors and put noid light on. at least u can tell if the DME is intentionally sending the signal to injectors

[mytrplseven]

Pull the vacuum hose off the FPR and see if theres a gasoline smell or wetness in there. Could be the Regulator is bad.

[mytrplseven]

Might also check the oxy sensor plugs at the rear of the engine. Pull the round connector apart and see what it does. This thing will cause the ECU to create a rich condition if it fails one way or another.

[eligunn]

Well, thanks everyone for your ideas. I think I'm going to put all my eggs in the fpr basket at this point. I just ordered one today, so I will let you know how it turns out.