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1988 Ford Mustang Fuel Problems

Alrighty, I'm going to start this from the begining. 2 days ago, my intank fuel pump in my 1988 Mustang LX 2.3 stopped humming. (good thing it died in my back yard). I went and bought a new fuel pump and dropped the tank. Before putting in the new one, I had a friend test the original one in the tank. The one just taken out of the tank is still working. (the one i bought wasn't funny enough) So we put back on the FULL gas tank with the original pump in it. Now the pump doesn't turn on when you go crank over the engine (the humming doesn't start). We checked all the fuses in and around the car. Searched and finally found the relay (under the drivers seat). We got a new relay, and it still doesn't work. But if you "override" the relay with a piece of wire, the pump will work but you still can't start the car. Can anyone give me an explanation quick? PLS HELP!

Reply to
Lori
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Check your EEC power relay too. It looks just like your fuel pump relay but is under the passenger side kick panel. The EEC relay powers up the inertia switch which then powers the fuel pump relay. HTH StuK

Reply to
Stuart&Janet

Stuart&Janet opined in news:RNS4b.339$ snipped-for-privacy@mantis.golden.net:

Well... not actually. The EEC relay powers up the eec, Which then can turn various other relays/solenoids on and off.

Including the Fuel pump relay. The inertia switch is only an interruptor in the line from the relay contact back to the fuel pump.

BUT

Stu's right about the EEC relay.. common failure and probably has corrosion/rust in it. WHen you install the new one, make sure the base is DOWN.

While you're down there, make sure the wiring ground lug (to metal just below the EEC) is making good contact and tight.

Reply to
Backyard Mechanic

Actually it applies + voltage to the inertia switch directly as well as the EEC then to the FP relay . The EEC actually completes the circuit after the fuel pump relay by grounding it, which would make your statement regarding grounding the EEC dead on.

Sometimes just giving the relay a kick gets em going again, BUT percussive maintenance is not a good long term strategy IMO.

BTW. I'm cheating. I have the EVTM but I've been down this road myself on a few cars. StuK

Reply to
Stuart&Janet

Stuart&Janet opined in news:rvT4b.347$ snipped-for-privacy@mantis.golden.net:

Okay.. on an 88?

The 87 has no such connection according to Mitchell which is pretty accurate.

BUT I ALSO have a 93 EVTM

And I see what you mean, but it isnt "powering up" the inertia switch, a switch is a switch.

Note that the power to the pump is supplied by the FPR... I'm looking at the

93-94 on the factory CD ROm and there is indeed a wire from the connection BETWEEN the FPR output and the supply side of the inertia switch. That is a "sense wire"..

The PCM internal circuit would SUPPLY 12volt from a high resistance on that pin. If the inertia switch or Fuel pump were open, then the PCM would see a positve voltage after the Fuel Pump Cycle finished. NOrmally after the cycle, the lead would be LOW.

If PCM has turned on the relay and the lead in question read LOW or NO voltage, it would flag a fault in the CCRM FP relay

That is how it can sense a Fuel Pump Circuit failure

AFAIK, that code, #95 or 96, is not relevant to an 88.

So YOu are right.. but I'm righter! ;)

Reply to
Backyard Mechanic

Ooops. Clarification!

Reply to
Backyard Mechanic

Reply to
Mike Fountain

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