help i have no fuel

[madchaz]

hi guy's i need help.i have an 85 notchback with a 5.0 ho and a throttle body injection.my entire fuel systems down.changed the pump the computer+3 relays that i found under the seat the dash and inner fender .inertia switch is bypassed.pump works if wired hot but no injection.any ideas?.thanks the mad one.

[badstanglx]

check wiring grounds to harness stuff like that

[Martin0660]

The 5.0 stuff isnt my bag, but a few thoughts......

Does the pump prime when you cycle the key? (should run a few seconds then off). On the later stuff, the computer needs to see a PIP signal to run the pump after the initial prime. So if it primes then nothing, I would look into the ignition as well. Not sure if that is TFI or not, but it could be the module, PIP, or wiring in around that.

Bob Myers

[madchaz]

thanks guys,i was thinking about grounds or a short,but wanted to see if i was missing something else.and the pump has no power from the key will not prime only when wired direct.but i have a few more ideas now.thanks again madchaz

[ArmyWarrant]

I would take a multimeter and verify that the relay under the seat is getting power from the computer and the ignition. I believe the wire from the computer is pink with a black stripe and from the ignition is red. If you have power there then go back to the fuel pump harness and do the same there.

If you have it at the relay and not at the pump then suspect faulty relay or faulty wiring between the relay and the pump.

If you don't have power at the relay I would suspect the computer is faulty.

My 91 had a bad spot in the computer where everything worked except the signal for the fuel pump. I had spark and everything but couldn't get the fuel pump to work except by jumping it direct.

[madchaz]

well i have power to relay under seat but not back to the pump unless i ground the inertia switch then the pump runs but still no injection.so i'm thinking it's foward to computer instead of back to pump?

[349Stroker]

There is most likely a ground out by the igniton coil on drivers side shock tower.It looks like an older glass fuse holder

make sure that is grounded

[ArmyWarrant]

Also check the ground by the ECM. Also I believe the fuel pump relay is grounded through the ECM so if that part of the ECM is bad then the fuel pump relay won't get its ground. Try grounding the fuel pump relay and see if it works. If it does I would try finding someone who has a known working ECM and see if it fixes the problem.