[Redsyris]

I have recently replaced a fuel pump in an 03 mustang gt 4.6. Now the fuel pump goes and does not stop even after starting is continuously pumping at a high rate i have no idea whats going on can anyone advise?

 

[blown245]

is it stock or aftermarket? some may just sound like it though i think you may know that. Could be a faulty pump or you could check the signal from the pcm side to see if has a flaw or if the pump does. pain in butt but you can troubleshoot the problem this way, maybe even smack the pump lol

 

[wmburns]

Did you use the correct fuel pump for the application? There is a difference between the return and return-less fuel pumps.

Do you have a fuel pressure gauge? If so, what does the fuel pressure do when the motor is turned off? Does it fall like a rock?

What other symptoms are you seeing?

On a return-less system the fuel pump is supposed to run all the time. The fuel pump driver module (FPDM) controls the speed of the fuel pump to match the motor's requirements. So I'm thinking two possibilities.

There a leak in the flexible line inside the tank which is causing to FP to work harder to overcome the leak.

Or your new fuel pump is just real noisy and you are just aware that the FP is running.

 

[Redsyris]

as of current im not quite aware of the pumps specifics my dumb roommate bought it off ebay it is supposed to be an oem replacement i can tell that the pump itself differs from the original pump ill get more detail on that when he gets off for now im combing the wiring ti see if anything got unplugged or stripped may also pull the pump and check everything there. as far as being the right application it was checked to be the right application

 

[Redsyris]

so after some wire tracing and everything its still doing it i still lack the specs it runs and drives normally but is now giving off a p1237 code fuel pump secondary circuit fault

 

[wmburns]

so after some wire tracing and everything its still doing it i still lack the specs it runs and drives normally but is now giving off a p1237 code fuel pump secondary circuit fault

Honestly from looking at the possible causes for a P1237 my best guess is there's a pinched wire somewhere in the fuel pump or wiring harness. Since your reported symptom is excessive fuel pressure, that would tend to indicate the short is to GROUND in the RETURN part of the circuits. Since the circuit is a ground start circuit, a short to ground in the circuit return would make the FP run at 100% duty cycle.

A short in the +12 volt supply side would likely blow a fuse.

I did help someone in the past with a problem blowing FP fuses. The FP would work perfectly when tested but would blow a fuse when trying to drive. It turned out to be a wire pinched between the FP hat and the gas tank. When the tank was lowered to test the FP, this broke the ground between the gas tank and the car's body. Thus allowing the test to work. However when the tank was pulled up into position, the tank's ground was restored thus blowing the fuse.

>>
P1237 - Fuel Pump Secondary Circuit Malfunction

Open or shorted FP PWR circuit
Open FP RTN circuit to FPDM
Open or shorted circuit in the fuel pump
Locked fuel pump rotor
Damaged FPDM

 

[Redsyris]

thank you wmburns im going to pull it and try to trouble shoot some more its been hard to get under it since work has me till 8 and my garage isn't the most eqqupied considering i have another car in there getting a head replacement but im going to drop it again and remove the pump and check all the wires worst comes to worst ill make the roommate send the pump back but i haven't found any blown fuses yet