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Old 12-22-2007, 05:55 PM   #19
pearce9906
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Join Date: Nov 2007
Location: OHIO
Posts: 20
Default Re: 88 lx 5.0 needs help!

Ok, more info. Took the Ignition module to be tested today, turns out it was bad, replaced it with a new one. No change to my current problem. (just a refresher, pump relay out and pump still runs, two hots, one constant, one switch one power) Turns out the switch on power is the supply to the fuel pump, pink and black, started checking the harness, past owner had byassed inertia switch, hacking into the pump harness with direct switch on power, also bypassing the relay. I fixed all the hacking, put new relay in, but now have no power to the pump.

Trying to track down problem, this is what I have so far:
1. at the relay, there are five wires, one is constant, two pink and black (one runs in harness towards front of car, unsure of where it goes, i would like to find out if anyone knows, the second pink and black goes to fuel pump), one wire comes into relay from the inertia switch, and one goes from relay to the ecm.
2. Constant power is constant, obiously. Switch on sends power through the inertia switch back to the relay, then this power goes to the ecm.
3. How does the ecm open the gate to the pump?
4. If I probe the wire going to the ecm with a test light, the relay clicks open and the pump runs, still doesn't prime and shut off like I think it should when the car isn't running though.

Anyone have a GOOD wiring diagram of the fuel relay circuit? Good being the operative word there.

By the way, code 87 is now the only code being pulled.
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