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Fuel Pump/ECM Issues 91 Sport Manual Tran

bpitman

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Joined
June 17, 2012
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City, State
Missoula, MT
Year, Model & Trim Level
1991 Ford Explorer
I have been having a helluva time with my 91 Explorer Sport (2 Door, Manual). Last Thursday it died at the store, got it restarted and it went about 100 yards before it acted like it was out of gas and died. After realizing that the fuel pump was not engaging I replaced the Fuel Pump, Fuel Filter and Fuel Pump Relay. Still wouldn't start, and the pump still wasn't engaging.

Had a buddy scan the PCM/ECM with a scanner. Scanner basically said that it wasn't attached to anything, the paperclip/test light test gave a solid light (no pulses) with the test light. So I concluded that the ECM was out... I got a used ECM with the same code (F07F-12A650-VA) on it.

Car started and ran BEAUTIFULLY. Better than it had before the issue by far, for about 21 miles (I set the Trip Odometer when I got it started). Then the Engine cut out as I was driving home, and would not start. Removed the battery cable for about 2-3 Minutes reattached it and it finally started (not easily though, rough, super-low RPM idle (400-500RPM) and then finally came back to life. Drove it to my house turned it off and tried to restart in front of the house immediately. Would not start, just grinds.

Does anyone have any ideas? Is this just an issue with the ECM needing to be re-programmed when it was installed? Or am I just F'd?

Please Help!
 












PCM has to have power before it can tell the fuel pump relay to close and power the fuel pump. IIRC, this:
Had a buddy scan the PCM/ECM with a scanner. Scanner basically said that it wasn't attached to anything, the paperclip/test light test gave a solid light (no pulses) with the test light.
would also be consistent with no power to the PCM. KOEO does the CEL come on (CEL is supposed to come on before starting to indicate that the PCM has power and is ready)? If the CEL is not coming on, I'd go straight to diagnosing the PCM power circuit.
 






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