Fuel system problem

**XM15** · 11-05-2013

First off, I just wanted to say that I appreciate the help I have received in the past from you folks. I have a new problem with my GTP.
2000 GTP S/C Series II

I had a problem previously with my fuel system and replaced the fuel pump, which did not fix it. I bent the connector over on the fuel pump relay and found the problem was the fuel pump speed resistor. I replaced the resistor and all was well for a few weeks. The car wouldn't start the other day and had to bend the connector over again indicating the resistor was bad, already. I haven't had the opportunity to pick up another yet and had another issue. The car wouldn't start again. I pulled both fuel pump relays and then replaced them after a minute or so and the car started right up. It did run pretty roughly (idling) for a short time then drove fine. The car has never died once it has started. It seems that it is on start-up that this issue occurs. I have turned the connector back so it runs through the resistor and it will still start and run fine, sometimes.

Any Ideas on what might be causing this besides a bad fuel pump or resistor?

**dsmuts** · 11-05-2013

Could be a dying pump

**XM15** · 11-05-2013

I thought that was the problem a few weeks ago too. My pump was still under warranty so I replaced it, and still had the same problem.

**BillBoost37** · 11-06-2013

I wouldn't condemn a pump without checking pressure. Maf can do this type of thing.

**XM15** · 11-06-2013

Ok, So I have done a little trouble shooting and here is what I have. Fuel pump is definitely good, the fuel pump relays are good, the fuel pump speed resistor is good.

I started the car and it ran fine for a while. Upon slowing in traffic it died and would not start again. When you turn the ignition on, but not engaging the starter the fuel pump does not cycle. Give it a while and turn the key on and off several time and the fuel pump will come on and it runs. Drive it a short distance and it dies again. The pump again does not cycle with the key being turned on. There is no power going to the pump now with the key.

My thought is a short somewhere in the relay/fuse box under the hood or a shorted wire somewhere.

Anyone else have this issue?

**BillBoost37** · 11-07-2013

Pump should have a fuse, not a circuit breaker. If there was a breaker, I'd look for a short to ground. Since you only get it when warmed up/running for a while...I think your observation/diagnosis is good.

**XM15** · 11-09-2013

So, here's where I'm at now. When I turn the ignition on the pump does not prime. There is no current going to the pump at all. The fuel gauge sender gets its power and works. The relays are getting their current when the key is initially turned on. I haven't been able to locate any wires that have been damaged as of yet.

Q: does the ECM control when the pump comes on before or after the relays? (ie.. Does the ECM control the relays?)

**XM15** · 11-09-2013

I found the problem, but not sure how to get to it to fix it without causing damage.

There is a loose connection inside my underhood fuse/relay panel where the fuel pump relay plugs in. I have removed the whole box, but I am no sure how to take it apart without possibly damaging it.

Does anyone know where a video os or a diagram of this.

Thanks for any help.