fuel pump problem

[mtbingdude]

I just replaced the head gasket on my 1995 windstar, and it ran great for 2 weeks, when im hit with another problem. No fuel, i traced it to the fuel pump. The pump runs when i hook up 12v battery to it, so the pump is good. The power wire has battery voltage and the ground is good. The pump doesnt run when its hooked up though, even though its got voltage. Its got me going in circles rechecking everything over and over... still cant find anything defective. any advice?

[mtbingdude]

UPDATE: just found out that power side has .4 voltage drop. any clues to where i am losing that?

[wiswind]

OK, on a 1995, the fuel pump relay is inside the CCRM (Constant Control Relay Module).
A fancy name for a small metal box with relays in it.
I have pictures of the CCRM in the pictures that the link in my signature takes you to.

Now, the FIRST thing that I would check is the fuel pump inertia shutoff switch.
This is a safety switch that is designed to turn off the fuel pump in the event of an accident.
Once tripped, it must be manualy reset.
This is located in the jack compartment.

Power flows through fuse "N" in the engine compartment fuse/relay box.
This is a 20 amp fuse.
From there, the power flows into the CCRM Pin 11 and through the relay contacts.....and out of the CCRM Pin 5

Then the power flows through a variety of wire harnesses and back to the Inertia Shutoff Switch, that is in the cargo area, in the jack compartment., then it goes through another wire harness and to the fuel pump.....then to ground.

The power to energize the coil of the fuel pump relay (inside the CCRM) comes from the PCM power relay, which is in the engine compartment fuse/relay box.


The way to reset the Inertia switch is to press down on the button......when it is set.....you can still push the button about 1/16".......and that is normal for when it is OK.
If that does not solve the problem.....try checking for power at that point, relative to a good ground....with the ignition ON.

[mtbingdude]

alright, im back to where i started. nothing seems be be wronge with anything in the circuit, i get battery voltage at the pump, but pump doesnt turn, unless i run another wire from the battery and use that instead. both wires test the same voltage but only the new wire turns the motor.

Edit: voltage drop is 309mv across the entire positive circuit.

[mtbingdude]

alright, i just jumped the pin 5 and pin 11 on the ccrm connector, and the motor worked. how do i go about checking to make sure the pcm is sending a signal to the relay?

[wiswind]

Fuel Pump Relay COIL leads on the CCRM are pin 13 (HOT) and 18 (to PCM pin 80).
The PCM provides a ground path for CCRM pin 13....to energize the relay coil, and turn ON the fuel pump.

[tripletdaddy]

It might be easier just to figure out if your relay is ok than the PCM. You've gotten this far. As Wiswind pointed out, to electrify the coil, it needs a ground at pin 18, so with the relay in run a jumper to pin 18 or to a wire that goes to pin18 from a good ground. Your pump then should run if the relay works and it should also give you a measurable 12 v at pin 5 which you previously jumped power to from pin 11 to test run the pump. I had tried troubleshooting the electrical system for an elusive problem with the fuel pump system like you are and got nowhere. Finally, just gave in and put in a new relay and problem was fixed even though the old relay had all the symptoms of a fully functional relay. I could actually get it to work everywhere except for the fuel pump. I think they get weak after awhile and don't work like they used to so like work kind of but not really. It works enough to carry a millivolt, which is what our testers work at, but not several volts that the pump requires.

[mtbingdude]

awesome, thank you guys very much.

[searcherrr]

Originally Posted by mtbingdude

awesome, thank you guys very much.

Whatever happened with this mtbingdude? Post back. I've got a strange problem I'm seeking info on that may be related to this too.

Also, if this helps anybody:

[mtbingdude]

I'm still here, I fixed my problem by replacing the ccrm with one i found at the junk yard. Everything runs like a dream now. Any questions feel free to ask away. again thanks for all the help guys.