I posted this in 5.0 tech too, but figured some here may be able to help too...
We're having trouble with my dad's '91GT. He was getting ready to have the engine bay painted and I talked him into hidding wires. Well, that has proven to be a bad idea as the car hasn't started for over a month now. When the key is turned forward, the fuel pump doesn't start. I've downloaded every wiring diagram I could get my hands on and we have checked and replaced both fuel pump relays (the on under the driver's seat and the one in the passenger side fenderwell) and the EEC power relay located above the computer. I put a meter on the old and new relays and the results are the same. On the FP relay under the seat, when the key is in the on position I have power to all wires except the green/yellow power wire that according to the diagrams I have goes to the fuel pump. At the FP inertia switch I'm getting a power reading with the key on, but it's only showing about 5 volts. I forgot my paper at my dad's that I listed the colors of the wires on, but the relay in the pass. side fender only had key on power in two fo the 4 wires there.
The other and I fear more serious problem is that we tried to pull the codes with a handheld code reader, when the key is switched on the reader usually beeps and the light flickers on it and then the codes start to come out. Now when the key is on the light goes dim and nothing else happens.
When hooking up all the hot wires we accidently put one to ground. This shouldn't have done anything bad as putting a ground to power would have.
So at this point we're out of ideas. I'm now fearing tha something is shorted in the EEC. I don't know how to test it. I read online that if the injector has power with the key on the EEC is good, but I believe that isn't true since I also read that the EEC activates various things by grounding the circuit. If this is the case then the injector should have power and the EEC would act to ground it to fire the injector.
I appreciate any and all help. I'll post back later with which color of wires had voltage and which did not.
We're having trouble with my dad's '91GT. He was getting ready to have the engine bay painted and I talked him into hidding wires. Well, that has proven to be a bad idea as the car hasn't started for over a month now. When the key is turned forward, the fuel pump doesn't start. I've downloaded every wiring diagram I could get my hands on and we have checked and replaced both fuel pump relays (the on under the driver's seat and the one in the passenger side fenderwell) and the EEC power relay located above the computer. I put a meter on the old and new relays and the results are the same. On the FP relay under the seat, when the key is in the on position I have power to all wires except the green/yellow power wire that according to the diagrams I have goes to the fuel pump. At the FP inertia switch I'm getting a power reading with the key on, but it's only showing about 5 volts. I forgot my paper at my dad's that I listed the colors of the wires on, but the relay in the pass. side fender only had key on power in two fo the 4 wires there.
The other and I fear more serious problem is that we tried to pull the codes with a handheld code reader, when the key is switched on the reader usually beeps and the light flickers on it and then the codes start to come out. Now when the key is on the light goes dim and nothing else happens.
When hooking up all the hot wires we accidently put one to ground. This shouldn't have done anything bad as putting a ground to power would have.
So at this point we're out of ideas. I'm now fearing tha something is shorted in the EEC. I don't know how to test it. I read online that if the injector has power with the key on the EEC is good, but I believe that isn't true since I also read that the EEC activates various things by grounding the circuit. If this is the case then the injector should have power and the EEC would act to ground it to fire the injector.
I appreciate any and all help. I'll post back later with which color of wires had voltage and which did not.