No start fuel pump??

[speedy_jody]

Hi,

I have a 2000 Grand Prix GTP 3.8 Supercharged that just turned 90000 miles. Well my problem is the car will not start. I figured it was a faulty fuel pump because the familiar buzz when you turn the key was gone, and I have no fuel pressure. I checked the fuse it was good, replaced the relays and then replaced the pump, still nothing. No buzz no start. Everything has been working normal, I just don't know where to go from here. Could it be related to the ignition switch?? Thanks for any possible help.

[BNaylor]

Its possible. Have you checked voltages with a multimeter?

At the fuel pump fuse or relay check for 12v. If missing then you can back track to the ignition switch.

[speedy_jody]

Thanks, I'll give those relays a test and let you know what I come up with.

[BNaylor]

Originally Posted by speedy_jody

Thanks, I'll give those relays a test and let you know what I come up with.

Best thing to do is start by checking the 12v at the fuel pump fuse (15 amp). If missing there then you have a problem going back to the battery or remote positive connection at the engine compartment fuse box since that fuse always has 12v present. It does not go through the ignition switch according to the GP service manual.

The fuel pump relay is energized by the PCM module when ignition is switched on. The fuel pump enable is an output directly out of the PCM to one side of the fuel pump relay. The other side of the coil is ground.

Also, check all the fuses to the PCM module such as PCM sense, etc.

You may have something such as a Passkey or theft deterrent problem preventing the fuel pump relay from energizing.

Good luck!

[speedy_jody]

ok,
I have tested the fuel pump relays and they are receiving power, the fuel pump fuse is good and there is power going to it, the ecm sense fuse is also good and has power. The ecm powers up the fuel pump and the fuse block has power to all the fuses and relays. Could I possibly have an ecm problem? This one is a stumper!

[BNaylor]

Originally Posted by speedy_jody

ok,
I have tested the fuel pump relays and they are receiving power, the fuel pump fuse is good and there is power going to it, the ecm sense fuse is also good and has power. The ecm powers up the fuel pump and the fuse block has power to all the fuses and relays. Could I possibly have an ecm problem? This one is a stumper!

If you listen carefully can you hear the fuel pump prime in the ignition run position? After the fuel pump and fuel pump speed relays it is noting but wiring and a straight shot to the fuel pump.

Have you tested fuel pressure at the fuel injector rail to see if the pump is putting out and the lines and fuel filter are good?

The output of the fuel pump speed relay is the last component before the fuel pump. There is a resistor but that would prevent the fuel pump speed relay from energizing.

You may have an ignition problem like the crank position sensor.

[speedy_jody]

I checked for fuel pressure and it is currently at 0. The fuel pump is silent when I turn the key. It dosen't seem to prime or activate in anyway at all. I would like to bypass the theft deterent system if possible, but can you? I'm not sure how to completely disable. The owners manual has procedures for changing the sensitivity of the alarm. You first remove the mall pgm fuse inside the glove box, then turn the ignition key to accessory, then turn the headlight switch from off to on, the car chimes from 1-4 times depending on the mode you want to be in. However, I don't think any of these option lets you override the starter interrupt in the passkey system. I really need to get a scanner!! Thanks for all the replies, hopefully we'll get this one figured out.

[BNaylor]

Originally Posted by speedy_jody

I checked for fuel pressure and it is currently at 0. The fuel pump is silent when I turn the key. It dosen't seem to prime or activate in anyway at all. I would like to bypass the theft deterent system if possible, but can you? I'm not sure how to completely disable. The owners manual has procedures for changing the sensitivity of the alarm. You first remove the mall pgm fuse inside the glove box, then turn the ignition key to accessory, then turn the headlight switch from off to on, the car chimes from 1-4 times depending on the mode you want to be in. However, I don't think any of these option lets you override the starter interrupt in the passkey system. I really need to get a scanner!! Thanks for all the replies, hopefully we'll get this one figured out.

Are you sure the fuel pump relay is energizing? Because it sure sounds like it is not.

As mentioned earlier the PCM controls the fuel pump relay. However, it is not the main control module that may or may not inhibit fuel pump enable. The enable signal comes from the body control module (BCM). The BCM controls theft deterrent.

Is your PCM stock or reprogrammed? You might check the 80 pin connectors on the PCM to make sure they are tight and also the connectors at the BCM located under the driver's side of the dash.

Other than that you could get the BCM scanned but that will be dealer only. A Tech II diagnostics machine is required. A regular obd-ii scanner will not detect GM Chassis codes associated with the BCM module.

[speedy_jody]

ok I have verified that the relays are in fact energizing. There is power to the fuel resistor it even cycles properly when you turn the key to on. My test light goes on for a couple seconds then off, just as the fuel pump should do. There is still power after the resistor, but I dont know where the wires go from there. Is it a straight shot to the fuel pump?? If so, is it possible I have a break in the wire? Or does the line proceed into some other device. Thanks for any help!

[BNaylor]

Originally Posted by speedy_jody

ok I have verified that the relays are in fact energizing. There is power to the fuel resistor it even cycles properly when you turn the key to on. My test light goes on for a couple seconds then off, just as the fuel pump should do. There is still power after the resistor, but I dont know where the wires go from there. Is it a straight shot to the fuel pump?? If so, is it possible I have a break in the wire? Or does the line proceed into some other device. Thanks for any help!

Just about a straight shot to the fuel pump according to the service manual. Since the fuel pump relays are in fact working I would rule out a PCM or BCM problem and go the direction of the fuel pump. You could remove the access cover at the trunk and check for 12v at the fuel pump connector. Maybe it was damaged or not put on properly when the last fuel pump was changed out. Also verify the ground is good because it must have a good ground. Also I would not rule out another bad fuel pump if you verify the voltage and ground is good at the fuel pump electrical connector. Good luck!

BTW - The fuel pump connector is the one closest to the rear of the car at the top of the fuel pump assembly. I can post a pic since I recently did a lot of fuel pump work.

Also, the gas tank level and float sensor use two of the pins on the same connector so make sure you get the right two.

[speedy_jody]

OK,
Sorry for the length of time to reply, but I do finally have a solution to this problem!! After many tests of the electrical system, I had to have my car checked by the shop.. I know its sad.. Anyway, the problem was simply in the wiring. Everything checked out fine from pump to relays, the problem was after the relays in the main power wire to the pump. Somehow, it showed an open circuit, and we found it to be a bad terminal. The tech report showed this to be located at terminal C200. I have no idea what that means, but it was repaired, $360.00 later and now all is well. The shop did tell me that without trying everything we tried, they would have probably tried to sell me a new fuel pump, then I could have paid for that and the electrical issue. So Thank You all for your help, I know by checking all these things I ended up saving a bundle. Problem fixed!! Hooray!!