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93 LX Fuel Pump will not prime?

2046 Views 7 Replies 3 Participants Last post by  TOM RENZO
Just recently purchased a 1993 Mustang LX (Little over a month ago).. Very very clean car with only 83,000 original miles. After having it about a week i went out one morning to crank it up and head to work, but it would just turn over and over but wouldn't start. I had it towed to the shop i bought it from. They had it all of a day, because it cranked right up for them the first time. Been driving it for 3 weeks since then with no problem. Then the same thing happened again this morning. Its baffling to me because the car runs so strong. The fuel pump does not prime (I know the noise), the inertia switch is fine. I dont have any diagnostic tools, but a friend is supposed to come over with some soon though. I just want to know if anybody has had a similar situation with these cars, and what they did.......... and i def. dont want to go the route some guys take and just start buying parts they "think" it could be.. wanna get it right the first time, and any help is greatly appreciated!!!


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most probabally the "ICRM" black box on the passanger side fender, it is not repairable, but it can be bypassed, you would have to get a wiring diagram and cut the 4 wires that control the internal relay, then add an aftermarket relay to the harness, or you could get a wiring diagram and find the wire that goes to the pump, cut that and feed it 12 volts, i don't reccomend it cause in a crash the pump continuously runs, or just replace the relay module but i think they're pricy, i had to cut and add relays to my taurus which had an icrm, the a/c and fan control relays are in the box as well, also the a/c diode and the ecm relay. if you need help with the wiring colours i have them. it could be a different problem but i'm pretty sure this is it, if it doesn't start again smack the box on the right strut tower see if it starts. don't hit it too hard you don't wanna ruin the whole box.
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could it be just the pump itself? I mean its a 20 year old car that hasn't been driven much. Thanks for the advice!
Well you will have to run the PUMP from the ALDL connector. This tests the relay and the pump as well. The secret to replacing the correct parts that are defective is proper trouble shooting. Good luck!!! Peace Tom:yelpleased::yelpleased::yelpleased:

Yes it can be a defective pump. That would be my first thought!!!
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yah of course it could be the pump thought you already checked that.
Chris i dont remember him saying he checked the PUMP???? He has an intermittent situation. That is the hardest thing to trouble shoot. He has to be ready when the pump fail to run to do diagnostic testing. Other than that i would suspect a bad inertia switch or a pump relay (IRCM ) Peace Tom:cooldude::cooldude::cooldude:
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i need to pay more attention.
No worry's Chris Peace Tom:bigthumbsup:bigthumbsup:bigthumbsup
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