Fuel pumps help?

[retfr8flyr]

I am at a dead stop currently in my TT install as we can't get the fuel pumps to fire. Got everything hooked up and turned the key on to check the fuel system for leaks and the pumps will not turn on. Have been going through everything for a week now and it all checks out, the wiring is correct, the diagnostic checks all show good but the PCM will not turn on the pumps. We even tried the stock setup and it’s the same. If you disconnect the pumps at the tank every check is good, once you connect the pumps you get a fuel control module out of limits code. If the pumps are wired direct they work so the pumps are good and both modules check out good. Needless to say I am very frustrated. Anyone have any ideas?




Earl

 

[me-gone]

Did you turn the key on?

 

[Hawgman]

Did you check the fuse? Did you check the fuel system cutoff switch in the drivers side footwell?

 

[KIMMER]

Double check the fuel pump relay under the hood and fuel cutoff switch like hawg said. I would start checking for power with the key on after the relay and work my way back until I found the item the power wasn't going through. If you don't have power past the relay, check for power before it, maybe it went bad...just throwing out a couple ideals. Hope you figure it out...wanna see that beast turn on!

 

[ChevyKiller]

Ditto on the cutoff switch. Didn't you cut it when you installed the pumps? Did you reset it?

 

[xvesnfpu]

Just a side note, and not sure if it has any relevance, but what happens when you run the diagnostic via the Info & Reset button on the dash? After my Whipple installation, but before I reflashed the PCM with the Ford calibration tool, I would get an error during the fuel diagnostic. I can't recall the error, and either way, it disappeared immediately after I flashed the PCM for the new fuel pump and fuel pump driver.

 

[retfr8flyr]

Thanks for the ideas guys but have already done all the suggested steps. My guy has the Ford scanner to do all the electronic testing through the port and everything checks good. All the wiring is good, we checked every wire in the harness and there is power and ground all the way to the pumps.



Earl

 

[Hawgman]

What pumps are they?

 

[retfr8flyr]

The Ford GT500 pump setup.

Earl

 

[ChevyKiller]

Probably a dumb question - but it is the complete kit, right? With extra DM and harness?

 

[retfr8flyr]

Yes Mark it's the complete kit.

Earl

 

[cekim]

how about the sensor side? Fuel rail pressure sensor hooked up? Have not looked at its failure mode (i.e. whether floating high means high pressure or low pressure), but certainly that might be confusing things.

 

[ChevyKiller]

Yes Mark it's the complete kit.

Earl

Is it the JDM or FRPP? I don't lik the wiring of the JDM version and the FRPP is pretty straight forward. I talked to some people today to try to help you out cause I was thinking perhaps the harness and DM culd be year specific for CPU compatibility but that's not an issue so the only other options that I can think of are...

#1 - the fuel level sensor - is it placed right? If the sensor is right, then that leaves...

#2 - may be just a bad harness. There could be an internal ground or other internal wiring problem. I know you have everything hooked up right so that leaves an issue in the wiring itself. If the fuel sensor is correct, then everyone I talked to agreed you see if you can swap the unit where you bought it for another kit. It really sounds like a bad harness to me.

 

[retfr8flyr]

Thanks for your efforts Mark. The fuel level sensor is working correctly and we checked every wire in the harness for continuity and they are all good. The thing that has us stumped is we connected the stock wiring and stock fuel pump basket back in the system and it does the same thing. It has to be something with the PCM but everything checks correctly. I guess the only thing to try next is a new PCM but I hate to pay for a new one when I know there was nothing wrong with this one when I shut it down and it hasn’t even had power attached to have screwed up.

Earl

 

[cekim]

What about fuel rail pressure? Checked the value at the PCM connector? Gone through the FPDM diag check-list in the manual?

What exactly was the code you got? ("out of range" - but what was the number?)

The PCM should spin up the pumps with the key on until it reaches the desired pressure - if the sensor there were wrong, disconnected, not functioning, etc... It would not spin them up...

 

[retfr8flyr]

I'm not sure what the number was I'll have to ask my guy, he was doing the testing with his scanner.

I forgot Mark it's the Ford Racing kit not the JDM.

Earl

 

[ChevyKiller]

Well that really throws a wrench in the mix. (doing it with stock)

Okay, so at least we know the pumps and harness are good. Geez, this is a stumper. I just can't imagine the whole cpu being bad. I like Cekim's idea that it may be the connector. Definitely rule that out before looking at a cpu.

Best of luck - this is a toughie.

 

[retfr8flyr]

Yes it’s driving me nuts. I’m an old school guy, cubic inches, cams and double pumper carbs, hell I’m just old period. This fuel injection, electronic throttle and everything controlled by the computer is way over my head but I’m trying to learn as I go.



Earl

 

[ChevyKiller]

You're preachin' to the choir, Earl....preachin' to the choir...lol

 

[retfr8flyr]

Hooray!! My guy found the problem and everything is now working correctly. Just have to put the entire interior of the car back together and will be back where we were two weeks ago. One of the wires from the PCM back to the fuel pump modules had somehow gotten chaffed and there were only about 4 filaments in a 10 filament wire that were not cut. The wire would check for continuity, because it was not grounding out, but would not carry the required voltage so the PCM would throw a code and not fire the pumps. He found it by tracing the wire and checking the voltages the entire length of the car. I won’t make FFW with the car now but at least I will get it running.



Earl