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-   -   Fuel pump not running.... (https://mustangforums.com/forum/general-tech/582574-fuel-pump-not-running.html)

uvastang 01-20-2010 06:37 PM

Fuel pump not running....
 
im not sure where to post this but im starting here.... i just swapped a 87 gt 5.0 engine trans rear end and all into my 93 4cyl. foxbody.. im doing a complete swap and have gotten almost everything but the exhaust on my 93... i changed over the computer and egine harness and kept the dash harness the same... my car will crank but the fuel pump is not running at all.. i have no pressure at the fuel lines on the engine... im wondering what i need to do to fix it?!?!.. the wiring diagrams ive tryed to look at arent much help and im not really certain if any of the fuel pump wires run through the engine harness or not???? anyone with any help would be great!!!!!

onlymustangfords 01-20-2010 06:57 PM

Is it a manual or automatic transmission?

By the difference in the years, and the fact that you kept the dash harness the same, I'm wondering if you have an issue with the neutral safety switch circuit or a clutch lockout switch? Also the early Fords had an inertia switch, that cuts out the pump in the event of an accident (or a big bump in the wrong place).

If it has one, and its been left open, it could be signaling the computer to shut off the pump.

P.S. I assume you already know whether or not the pump is good and that it is getting voltage.

uvastang 01-20-2010 07:16 PM

i have both cars.. the 87 and 93 sitting side by side and both ran and we had put a new pump in the gt but the 93 pump is good but im not sure that its gettin voltage now... i cant really find anything that looks like the same wires.. ive looked for the relay but cant find it.. but its a 5 speed... i really just dont know where to start looking or what im looking for really....

onlymustangfords 01-21-2010 02:58 PM

See if you can isolate the fuel pump wiring and try to power up the pump on its own. If that works, then work backwards by following the wires back through the harness to the fuel pump relay ( open up the cover and see the colors of the wires) and see if it's sending power down the wire to the pump and/or is power going to the relay to send the power to the pump.

Some place on the way back, something won't work. Pump, back to relay, back to relay power, back to switch etc..

Rather than cutting the wires, you could get a pump connector from your local parts store. They should have a listing for the connector in their ignition book or in the computer. (bluestreak,echlin etc..).

Then run direct power to it to see if it runs.

From the relay back, you should be able to disconnect wires fairly easily.

MustangBradley 01-22-2010 02:04 PM

On the 94&95 mustangs, the fuel pump receives power from two sources. The computer sends voltage to the pump for the 2 seconds of priming you hear when you first turn the key. Then, once the engine is running, the Constant Control Relay Module supplies constant power to the pump. I don't know if the 93, let alone the 87 uses a CCRM. This post may give you a new path to look at but what you should do is get a Haynes manual for for the 93 and that will have a wiring diagram in it that shows how the fuel pump is powered.

john89gt 01-23-2010 08:41 PM

http://www.veryuseful.com will give you all the wiring diagrams you should need if that will help?


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