I just aquired a 86 5.0 TPI trans am that i cannot for the life of me get to prime the fuel pump. It was running fine a few weeks ago, but then after installing a new alternator and maf sensor it wont prime.

I have been one the forums looking at old posts trying to figure this out for weeks and i cannot get it to work. I cannot find the inline fuse in the engine bay, if there even is one. Fuses all look good in the box, i tried tracing all the wires and if i remember correctly 2 go to the ecu, 1 to the aldl port 1 around the aldl port (believe it goes there too) and one i have no idea (which according to wiring diagrams is the one that goes to the engine bay fuse...)
I have checked grounds at the pump, i am getting no voltage to the power wire on the junction behind the rear seats. Sending unit works great. Replaced pump with a good one, replaced relay with a good one and still nothing.

Only thing i can think of is maybe the ecu is bad? It is just hanging in the pass footwell...

 

It's very cleverly disguised, here's a couple of pics.....

 

ive looked there but cant seem to find it, nor find remnants of it. Is that the only location for an 86?

 

My fuel pump isn't priming on my 90 GTA (TPI) also. The fuse pointed out above tested OK on mine, as do the relays that the orange power wires lead to (since orange wires go to 3 different relays mounted on driver's side upper firewall I test all of them and they all are good... get a audible click and get good continuity once energized). My engine cranks strong, but no fuel pump prime "hum" sound.

This shouldn't be a battery problem, right? I mean if the starter motor cranks well then there shouldn't be a power supply problem to a dinky little fuel pump right...

My guess is the fuel pump went **** up or a mouse chewed on the power wire leading to the fuel pump.

I also depressed the valve nipple on the TPI fuel rail and noticed no pressurized hissing and no fuel drip (figured that would be the case but why not).

If the gas tank went dry, would the fuel pump still make the typical prime hum sound? I would think so. Thought I would ask as there is a slight possibility that the tank is dry.

Thought I'd post before getting into the fuel tank.

 

I would check the fuel pump bulkhead C313 connector between the seats, you can probe the wires on the inside or get underneath the car and disconnect the fuel pump connector, you should have a constant 12 vdc on the orange wire, if you do than check continuity to ground on the black wire, if you have both of these I would suspect the fuel pump has failed or wiring the tank has lost connection.