Fuel Pump and/or FPDM issue?

[bbayne35]

A couple of days ago, I had a no start normal crank condition. Ultimately, I disconnected the MAF, and it started. I shut it off, reconnected the MAF, and it started again. I cleaned the MAF, and it seemed fine.

This morning, no start normal crank again. I did not hear the fuel pump this morning. So, I checked voltage going in and going out of the IFS switch. 12V in and out. I also had 12V going in to the FPDM. Per a post by wmburns, I also checked the voltage at the connector located under the car by the rear bumper behind the gas tank (C420 on my 2000 GT). This is the connector that goes to the fuel pump. With the key on, I had 12V at the BN/PK wire constantly. In other words, I measured 12V beyond the 3 seconds or so that the fuel pump is supposed to switch on. We turned the key off and then back on so I could check the voltage at the RD/BK wire, and I saw no voltage. Are these readings normal?

I reconnected C420 and disconnected the FPDM connector. I jumpered the FPDM PWR (PK/BK) to the FP PWR (BN/PK) and grounded the RD/BK to the grounding screw next to the FPDM. I heard the fuel pump click on. So, we reconnected the FPDM connector, and the car started. We shut it off, I turned the key on and heard the pump, and it started again.

So, what do you guys think? Does a fuel pump start working intermittently when it is about to fail? Were my voltage readings at C420 correct? Is the FPDM beginning to fail?

Thanks!

 

[musclemustangcb]

I have seen cases where a fuel pump will.stick and not run, but then free up and run. Its very possible to have it be intermittent. The fpdm can also be intermittent.

 

[bbayne35]

I did some more testing. I have a Predator tuner, so I decided to monitor Fuel Pressure. When I first started the car, it was at 40 psi, but quickly dropped to about 7 psi. The car was running a little rough at idle. As soon as I stepped on the accelerator, the RPMs dropped and it stalled. I manually ran the fuel pump as described above, but I measured the current this time. The fuel pump ran, and the current was just under 7 amps, which I believe is normal (correct me if I am wrong). I re-connected the FPDM, and the car started with the fuel pressure staying around 40 psi. I manually ran the fuel pump once again to be sure, and it ran again. The pressure stayed around 35-40 again.

So, I am concluding that the fuel pump is functioning and that the FPDM is working intermittently. My plan is to replace the FPDM. Does this sound correct?

 

[musclemustangcb]

It's hard to diagnose with out being there, but it sounds like ur definitely heading in the right direction.

 

[bbayne35]

I installed the new FPDM. The car started, and the fuel pump seemed to prime with each key on. I used my Predator to monitor fuel pressure, and took the car for a drive. It started fine, but the pressure gradually dropped to about 7 psi. I barely got it back in the garage before it stalled. I ordered a new fuel pump (and grommet). I have a full tank of gas. What is the best way for me to drain the tank? I have done some searching, and running the fuel pump manually may not be an option if it is no longer working. Is there another way to siphon the gas out? Thanks.

 

[ouray19]

This may be a silly question, but have you checked the fuel filter. If everything electrical is working but pressure is falling off, could be something as simple as the filter.
As far as draining the tank, following info was given me by member wmburns;

If what you are trying to do is drain the tank, I can help. Disconnect the fuel filter and place a hose to direct the gas into a container.

Find connector C240. C240 is in the rear center of the gas tank under the bumper. It is a round connector the is easily visible from the rear of the car.

Open the connector and inject 12 volts to the RD/BK and BN/PK wires TOWARDS the fuel pump. This will make the fuel pump run at 100%. If nothing comes out, reverse the leads.

Hope this info helps

 

[bbayne35]

I last changed the filter 15000 miles ago. I tried running the fuel pump with external power, but it was not working. I bought a cheap ($45 from Advance) micro electric fuel pump and connected that to an external 12V. I clamped a tube to the output of the fuel filter that went to the micro fuel pump which then went to a gas can. It worked. It took about 30 minutes or so to drain 11 gallons. I tried using a drill pump, but had no luck. We dropped the tank and installed the new fuel pump. I managed to snap a small plastic sleeve that goes from the EVAP canister tube to the canister. The Ford manual says to disconnect the connector prior to dropping the tank. But, the yellow R-clip on the connector is a bit of pain, and the plastic sleeve going in to the canister apparently cannot take much wiggling. My recommendation is to remove that sleeve from the canister instead of disconnecting the connector. You can carefully pry it out with a flat head screwdriver. I used epoxy and electrical tape to put the sleeve back together, but I ordered one from Ford to install later. If you end up snapping it like I did, it is part number XR3Z-9E629-DB. By the way, I took out the fuel filler neck and took a look at the check valve. Definitely no siphoning through the filler neck!