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Discussion Starter #1
My 90 5.0 will start and run for maybe a minute before the rail pressure drops and the car stalls and dies. I have replaced the spark plugs/plug wires/ alternator/ distributor cap&rotor/ Battery Terminals and just replaced the Fuel filter and installed a Holley Fuel pump (255lph). Please help.
 

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You try replacing the relay for the fuel pump? Sounds like it is priming but not switching to run.
 

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Discussion Starter #3
It ran for a close to a minute before it stalled. If the relay was not working wouldn't it die right after starting?
 

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Discussion Starter #5
I heard it before we started it then after it died when trying to restart it the fuel pump did not make any noise.
 

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I would suspect the relay, but you did not answer the question. WHILE it was runnning did you hear the pump?
 

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Discussion Starter #7
Are the relay and the fuel pump regulator the same thing?
 

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Pull the relay put in a jumper to give then pump 12v see if it starts and runs. If it does you narrowed it to the relay or the circuit.
 

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Discussion Starter #9
Where is the relay? How can I charge it to 12volts?
 

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relay is under the driver seat or on the pass fender wall. I believe 90 is still under the seat. Pull the relay put a jumper in the biggest power wire holes PINK and ?. There is another way to test also ground in the wire on the eec test port but I think that is for when you have no fuel pump at all. The fuel pressure reg is something else and not your issue.

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
 

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Could also check the inertia switch to be pushed but that shouldnt be it since the pump came on once.
 

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Discussion Starter #12
I couldn't find the Inertia switch on the drivers side firewall, but the car did start and run at about 37psi on the rail gauge before stalling.
 

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Was the fuel pressure still there after it died? Pull the ECM out of pass kick panel check it for corrosion inside. If there is then you may need to replace it. Also check the 10 pin conn (salt and pepper shakerstoward rear pass of motor) maybe add some dielectric grease to them. Otherwise may just be the PIP in the dizzy.

YOu may consider pulling the codes for the heck of it.
 
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