<X style="MARGIN: 0px">My dad is the original owner and he said he took this truck to Ford twice for problems with the front tank and when on the front tank the fuel gauge would go up and down, or just stick in one place. The second time he took it in they didn't fix the problem and he just stopped using the front tank.<XX>
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<X style="MARGIN: 0px">I'd bet you they replaced the friend wiring, but not the problem when he had the truck since where the wiring has friend again, is below the splice to the fuel inertia box and the harness with red/yel wire that melted together.<XX>
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<X style="MARGIN: 0px">I noticed that red/yel wire too, but just figured Ford changed it at some point, but now I think it was changed under the warranty work my dad had done.<XX>
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<X style="MARGIN: 0px">Here is my plan: I'm going to replace the whole front tank fuel pump assembly, and pull that whole harness out all the way to the front tank and replace it all. I'm also thinking about replacing that fuel inertia box since it got real hot there too.<XX>
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<X style="MARGIN: 0px">Do you think this will work?

 

Pull out the tank, change the module, inspect as much of the wiring as you can see. These are all reasonable actions and attack the most likely suspects.

Unfortunately, the short could be anywhere along the path downstream from selector switch to the tank. Maybe somebody ran a sheet metal screw through the wire in adding some accessory. Maybe the harness got pinched between the bed and the frame, or under the body somewhere. That could be why the problem is intermittant. Tracing this sort of thing down is not something dealerships like to do under warranty -- there's no good flat-rate entry for "troubleshooting".

If you can find an obvious explanation, fix it and move on. If you can't find the short, I would suggest replacing the fusible link or even adding a secondary 30 amp maxi-fuse to the circuit, just to prevent this level of wiring carnage if/when the short circuit happens again.

 

I got an idea this morning that I think might save me some time and money.<XXXX>
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<XXX>I'm going to cut the bad wiring out of the harness and replace it (splice in new wire) and buy a new selector switch. Then I'm going to lift the bed off and replace the entire from pump assembly with seder and all. I will fire it up and see how it runs and see if the harness fries again. That will let me know a bad ground wire is some where.<XXXX>
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<XXX>I don't think the fuel inertia is the problem as it ran fine on the rear tank until I used the front and it screwed up the wiring again. According to my dad, this only happened after he tried to use the front tank also.<XXXX>
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<XXX>Good plan?

 

I bought the whole intank fuel pump assy, and 3 new 30A fuse links to put in the place of the burnt wiring temp to see if after I replace the pump assy there is still a short. I hope it will blow the fuse and not fry anything else if there still is a problem in the wiring. After I see that the short is gone, I will buy a new harness to replace the bad section with. I just don't want to spend $$$ on a new Ford harness and have it fry again.

Wish me luck for when work on it this weekend!

 

I seem to have cured a few problems now.

I replaced the whole front tank lift pump assembly and now the fuel gauge in the dash works. I also have not fried anymore wiring since the fix. I guess it must have been nothing more than the front tank pump the whole time.

Now on to some new things. I replaced the fuel inertia wire with a fused link as well as the two wires in the harness up to the selector switch that were melted with fused links. I bought a brand new Ford OEM tank selector switch as well.

I found other wires that had touched the fuel system wires in the main harness that had melted together, but not near as bad. I separated those, cut, and respliced some new wire in its place.

Now for the three problems I have left.....

(1) I now have a right blinker problem. When I turn the head lights on, the right blinker indicator light on the dash stays on. With the lights off the right blinker doesn't blink at all, the blinker and tail light just stay on. I can manually work the blinker though and make it turn on and off. I put new bulbs in, so that isn’t the problem.

Any ideas where to look for a short in this area, or what to look for? I’m thinking the fuel wires melted in to the right blinker or something and messed up something.

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(2) It runs now, but it seems to not be running as smooth as it should be. If you look at the motor at idle, or the shifter, you can see a miss, or it shake some. Keep in mind this may be sort of normal being it has 230k miles on it.

When I test drove the thing in my neighborhood after letting it idle for like 30 minutes in the driveway it seemed to have power for a while, then going up a hill shifting from 2nd to 3rd if felt like it bogged, or lost power.

There is a pipe that runs on the backside of the engine and it has a rubber hose that goes to a funny thing almost like an EGR valve, and the hose keep blowing off of it. Like in the yard I ran it up to like 2400rpms for a couple minutes, then floored it to 4000 rpms and let off. It seemed to bog some, then it made a backfire noise and blew that hose off.

Could this be a stopped up catalytic converter and or a bad oxygen sensor? This thing still has the original cats and O2 sensors on it.

I have done new plugs, plug wires, EGR, EEC relay and Fuel relay along with a new inline fuel pump and front intank pump. Fuel pressure is like 31psi at idle and shoots up to 40psi when gassed; when the vacuum line is off the FPR it also shows 40psi.

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(3) If you go back to the first posts with links to pictures of the fried fuel wiring, the second connector is all melted from getting hot and I can't get it to unclip. None of the wiring inside is touching, or getting hot, so should I leave it alone, or order that whole new harness just to be safe?

I was going to just chop it out and splice the wires together until I noticed that like 7 wires go in this thing, but only 6 come out, so I don't know what it does, or how to splice in a generic new connector.

Thanks for the advice and help all! This site is the best!

John

 

I'd probably leave the harness connector alone, assuming the wires look like they're not broken and any bare sections get taped.

The rubber hose thing at the back of the engine sounds like part of the air pump system. Blowing that hose off and your bogging under load symptoms could indicate a plugged exhaust system. The O2 sensor generally does not impact engine running at wide open throttle -- I doubt this is causing the boggging, although replacing the O2 sensor might be indicated for other reasons (high miles, rough idle, etc).

As for the right turn, first check the grounding of the taillight assembly. Bad grounding can cause strange feedback from the running lights back to the stop/turn circuit. If this looks OK, use a test light. Turn on the headlights, leave the turn signal off. Probe the wire going to the right stop/turn indicator. If 12 volts is present, trace the wire back and figure out where it is getting the 12 volts from.