Recently picked up an 87 GT with the V6, Has a new fuel pump, fuel pump relay, relay wiring, and ECM (all replaced by the previous owner no less than 1 month before i purchased the car, due to the no start condition). Fuel Relay has not worked since I got the car 3 months ago, but allways started and ran on the oil pressure back up. Oil pressure sender went bad and the car died, I replaced the sender and everything seemed to work great, then this morning it started fine, ran for about 30 seconds and died. Shows oil pressure when cranking, but no pressure at the fuel rail. What steps can I take to check the operation of the fuel pump prior to replaceing it, and how hard is it to chase all of the wires and replace them.

Pin G of the ALDL is a direct wire to the fuel pump. Apply +12 to that wire and see if the fuel pump runs. The ALDL is under the cig lighter panel. You can also test to see if the Oil Pressure Switch, or Relay is applying +12 at this pin. Either the Oil Pressure switch OR the relay can supply voltage to the fuel pump



The Fuel pump relay is right behind the drivers seat, inside the engine compartment, behind the air cleaner canister, on the firewall. The relay should click when you turn the key to on.

Right behind the passengers seat in the engine compartment also on the firewall is a yellow connector. This is the connector to the gas tank. The black wire is ground. The Tan/White wire is to the fuel pump. The other wire (pink or purple) is for the gauge.

[This message has been edited by phonedawgz (edited 01-26-2011).]

Thanks for the info, I will check it when i get off work today.

Wow, I should have cleaned up my console before taking that picture.

You have checked your fuel pump fuse i assume ?

Put 12v power to the G conecter and now the fuel pump works as it should, turns on when the key is turned on and runs for a second or 2 after it is turned off, maybe it just needed a jumpstart? Runs great and even the shaking in oil pressure guage has gone away. Thanks again for the info.

That's weird.

I have to assume you don't have +12 wired to G all the time.

I take it that you applied +12 to G, and that 'started' the pump then, and somehow that 'fixed' the problem??

If so I suggest you use a volt meter to measure the actual voltage on pin G when the car is running. If that voltage is more than 1.5v below battery voltage you have a trouble that will come back. The big thing is that low voltage cause the pump to take more current for the same amount of power to run the pump. What that does is overheat the windings and burns out the pump. New pumps many times fail when replaced. They do that because what made the pump fail originally is low voltage to the pump. Considering what a pita it is to replace the pump, I'd strongly suggest checking the voltage. Also it's not just the relay that can cause low voltage there. It can also be a bad relay socket. The oil pressure switch if working correctly should also help make sure you have full voltage at pin G. Bottom line -Check the voltage on Pin G to ground.