Hi, I am tryong to bring back to life a 1987 GTA 350TPI after sitting for 15 years. I have changed the injectors, fuel tank, sending unit, fuel pump, relays fuel pressure regulator diapram.
I installed everything and the car would only start when the intake was duped.
saw that the fuel pressure was 40 at start but would fall to 10. eventually the fuel pump died. checking voltatages, its 12.4 everywhere in the fuel circuit except the plug behind the back seat were the sending unit connects.it is 11.9v.
Can anyone tell me where those individual wires go without me ripping the carpet out?
thanks for any help.

 

The ground goes to an eyelet under the driver's rear seat cushion. Check there for corrosion causing your voltage drop. If the 11.9 is being measured between your power and chassis ground, the power wire goes in one continuous run to c100 then to the fuel pump relay under hood. There is a fuse holder mounted to the inner fender on the passenger side just beging the headlight that provides power to the relay. Check to make sure that fuse isn't melted or burned.

 

I noticed that in my 88 IROC LO3 G304 (fuel pump ground) was located just forward of the driver's front seat. Before hand I searched hi and low on the rear seat area but ultimately traced it towards the front of the car.

To gain access I removed the sill plate, pulled the carpet just far enough (a few inches) to access it.

But, 11.9 volts at the fuel pump connector doesn't seem to alarming considering the run. Curious what it is when the key is turned on to prime for 2 seconds - what's the voltage drop then? Is that drop a larger number? You could also raise the vehicle, pull the connector and ohm the circuit to test wiring and pump for hi resistance.

 

Thanks for the tips. Will follow and report back.

 

Ok got the new pump installed and I am getting good pressure. Car will only start when duped and then die. So will start a step by step trouble shoot.

 

What do you mean by "duped"?