No Fuel Pressure, Need help

[Wolfhound]

I have a 2002 Ford Explore Sport Trac 4.0 with a problem I cannot find. There is no fuel pressure coming to the motor. The Fuel pump assembly with fuel pressure regulator is new, the fuel filter is new, all relays have been checked, all fuel lines have been checked, test fuel cut off switch, and the fuel rail and injectors have been cleaned. I am a mechanic and have been boggled by this mystery. My last idea is it could be the ECM. Pump was test and puts out 55 to 65 PSI no problem when powered directly. Anybody have any ideas on something I have overlooked that controls power to the fuel pump to cut out.

Thank-you.

 

[Squirrelmaster]

I know you mentioned the fuel cut-off switch, but I don't know what exactly you did to test it so I'll toss this idea out to you: fully cycle the switch. I had a problem very similar as yours on my old '95 X, and the switch seemed like it was functioning fine as near as I could tell. I finally became so fed up that I nailed the switch as hard as I could with my fist, fully tripping it, and when I reset it the fuel pump turned on. I guess as the switches age, they become a bit finicky about how much they really feel like working. Just a tip I had, and if you've already done so, I'm afraid I can't be too much more help besides saying to rotate the relays and verify their all good (another problem I had ). Best of luck.

Tom

 

[Dannyboy]

Hmm, I was dealing with my fuel system a few weeks ago but it's on an older truck and I would say you are right on with everything you are checking.

I got referred to a test that helped me out a bunch but I'm sure your truck is different. I would test out your wires, since it sounds to me like you are not getting power back to the fuel pump?

From what you've told me I would think it's electric. So to narrow down the steps you have taken


The Fuel pump assembly with fuel pressure regulator is new, Good, sounds like you tested this directly to current to test with a jumper wire or something
the fuel filter is new, good, yet irrelevant if you are not getting power to pump
all relays have been checked, good,
all fuel lines have been checked, good, irrelevant if you are not getting power to pump
test fuel cut off switch, did you zero this out with an ohm meter to test?
fuel rail and injectors have been cleaned. good, irrelevant if you are not getting power to pump

I would get out your voltage meter and "zero" out the ohms at each leg of the circuit starting at the ECM, this is where you send a signal to your relay to kick on the pump. Make sure you are getting power here, then it goes through the emergency turn-off switch, if you still have power here, then test between the emergency shut off switch and the pump. Could be a bad connection in a harness someplace.

I can point you towards a couple of threads if I'm unclear here but I'm pretty sure that is the route power travels from the ECM to your fuel pump. If the pump is getting power and running then it is a totally unrelated problem.

Is the truck not running at all?
have you tried a jumper wire while the fuel pump is installed in the tank?

 

[bdmaash]

- so did you check:
for voltage at the pump
for voltage at the relay
for voltage at the fuse

if it's the ECM, the control voltage for the fuel pump relay won't be there
if there's no control signal, check ECM relay and fuse first

 

[Wolfhound]

Thank-you everybody for the tips! Tom, I unplugged the cut-off and jump the plug and there was no success. I think I may have found the problem. I will post if it fixes it.

 

[chad551]

Did you check the gas tank to see if there was gas in it?

 

[Wolfhound]

LOL, has a half tank of fuel in it.

Here was the problem:

Dead Wire feed. The dead wire was from the connector from the cab to frame, then all the way to pump connector. It was a heavy pink with black stripe wire causing the problem. Could not find the break, so jumper wire was made. Truck runs good now with 65 Psi fuel pressure.


Again, thanks for the insights.

 

[Dannyboy]

Good to hear, I've learned so much in the past year about testing circuits. A toner is a fantastic tool for tracing and identifying wires for those who are reading this as well.