Any Ford techs about? F350 fuel trouble...

[bjcsc]

My 1993 5.7L 4wd F350 has some kind of fuel trouble. It has dual tanks, and neither pump energizes when the key is turned on. It quit all of a sudden at the end of my driveway, which unfortunately is a half-mile long (no fun dragging it back). All fuses check with a meter, 3 underhood relays seem fine (replaced each with new, one at a time - no change). Either A) no power is going to the fuel pumps or B) both pumps failed at exactly the same time. I'm thinking that whatever the tank selection switch controls has failed, but I don't know. Any ideas?

 

[bjcsc]

Re: Any Ford techs about? F350 fuel trouble...

New info. I had some time to look into it a little further. I have no spark. I am assuming coil or module, but would their failure cause the fuel pump(s) to not run? Do they only run once until the engine is started?

 

[Reel Poor]

Re: Any Ford techs about? F350 fuel trouble...

Check the connector in the small ground wire at the battery negative terminal. Also check all the fuseable links connected to the starter solenoid.

 

[jimr]

Re: Any Ford techs about? F350 fuel trouble...

I beleive the module tells the fuel pump to fire up if no spark or fuel that is where I would start. When I worked in a private shop I always kept a known good spare around for a tester.

 

[dolluper]

Re: Any Ford techs about? F350 fuel trouble...

Mods work with fuel delivery { injectors} not the fuel pump

 

[bjcsc]

Re: Any Ford techs about? F350 fuel trouble...

Yeah, I'm getting nowhere fast. Replaced both the coil and the module with no change. I did not recheck for spark yet, but will today. It's just short of being beyond me...might have to take it in...

But the good news is, I had developed a small coolant leak (could only smell it, no drips) in my 2003 F450, took it into Ford and it was a warrantable repair!

The 1-ton has me baffled...

 

[Windykid]

Re: Any Ford techs about? F350 fuel trouble...

You should get spark now. Also look at schematics for an oil pressure sensor. Auto manufacturers Put the fuel pump power in lin with these. If you lost oil pressure it was a fail safe and interupt the fuel pump to save the engine.

Also check all grounds an connections.

 

[SS MAYFLOAT]

Re: Any Ford techs about? F350 fuel trouble...

Most Fords have a roll over switch. Most are located on the firewall under the dash towards the center on the passenger side. Sometimes it is behind the floor mat. Sometimes they will trip shutting off the ignition and fuel system. They have a reset that can be pushed back in. That is where I would try first. Once in awhile a big bump will trip them even though they aint surpose to.

 

[darrklim2]

Re: Any Ford techs about? F350 fuel trouble...

New info. I had some time to look into it a little further. I have no spark. I am assuming coil or module, but would their failure cause the fuel pump(s) to not run? Do they only run once until the engine is started?

I don't work on fords but from my experience. Electric fuel pumps only run when the fuel lines loose pressure.(and when you first turn on the key) If your not pumping fuel into the cylinders, the lines won't lose pressure. Do you have fuel at the cylinders?

 

[darrklim2]

Re: Any Ford techs about? F350 fuel trouble...

Most Fords have a roll over switch. Most are located on the firewall under the dash towards the center on the passenger side. Sometimes it is behind the floor mat. Sometimes they will trip shutting off the ignition and fuel system. They have a reset that can be pushed back in. That is where I would try first. Once in awhile a big bump will trip them even though they aint surpose to.

I didn't see this until after my post. I have seen this many times on friends vehicles, hit a bump car dies, reset switch, away you go. Gotta love Fords!!!

 

[bjcsc]

Re: Any Ford techs about? F350 fuel trouble...

I don't work on fords but from my experience. Electric fuel pumps only run when the fuel lines loose pressure.(and when you first turn on the key) If your not pumping fuel into the cylinders, the lines won't lose pressure. Do you have fuel at the cylinders?

I'm guessing I do because I can smell it at the tailpipe while cranking. I get nothing when I turn the key to run, but I remember always hearing the pump before. ?

Never new about the rollover switch. Come to think of it, I did roll it over right before this happened!

JK, but I'm going to go see if I can find it...sounds promising!

Oil level is fine, but will look for that switch as well.

Haven't rechecked for spark yet, but will tonight. I'll let you guys know what I find and thanks for the help...

 

[bjcsc]

Re: Any Ford techs about? F350 fuel trouble...

I found the rollover switch on the passenger side, right behind the side panel where the door hinges are. There's even a little cutout in the panel so you can reach the pushbutton. The button was still in, I pushed on it but it didn't move and I don't think it was tripped...no dice...

I still don't have spark, though. I wonder if the distributor or any of its parts could have failed all of a sudden?

 

[SS MAYFLOAT]

Re: Any Ford techs about? F350 fuel trouble...

There is a Ford Enthusist (sp) Truck web site that I use for finding out things on my F350. Lots of help and info there. Another member of iboats turned me onto the site years ago. Good Luck.

My F350 doesn't have spark, ,,,,,,but it is a diesel

 

[KBADC]

Re: Any Ford techs about? F350 fuel trouble...

I didn't see this until after my post. I have seen this many times on friends vehicles, hit a bump car dies, reset switch, away you go. Gotta love Fords!!!

That is a faulty switch. Nothing more.

 

[Autotech1]

Re: Any Ford techs about? F350 fuel trouble...

fuel pumps are energized for 2 seconds when the key is switched to run. After that a crank signal is required in order for the pcm to energize the fuel pump. check your crank and cam sensor both for signal. Use a voltmeter, your just looking for an on/off signal between the two wires.

 

[Blue Water Runner]

Re: Any Ford techs about? F350 fuel trouble...

EEC power relay? If the PCM is not powered up then there will not be any fuel or fire because it controls both. I am trying to remember where it is located. I am not a tech. I am a parts guy.

 

[bjcsc]

Re: Any Ford techs about? F350 fuel trouble...

Well it appears to be a faulty engine computer. Shop wants ~$750 to start for replacing it. I can get a rebuilt one for $200. Does anyone know where it is located on the truck and how I would get to it?
​

 

[Reel Poor]

Re: Any Ford techs about? F350 fuel trouble...

It's possible it's the control module but I have my doubts. Anyway the connector and the retaining nuts are located under and just to the drivers side door of the brake booster. On this model if I remember correctly once you disconnect the module harness and the two retaining nuts the module is removed from under the dash.

The most common problem are the distributor TFI module or the ground wire I mentioned earlier also a faulty power relay.

 

[bjcsc]

Re: Any Ford techs about? F350 fuel trouble...

Thanks RP. It's at the shop now; they diagnosed the problem and called to see if I wanted them to fix it or fix it myself. Is it pretty straightforward to R/R? (Sounds like it is)

 

[bigtwin]

Re: Any Ford techs about? F350 fuel trouble...

I worked as a tech. for Ford for 13 years and I have replaced lots of faulty PCMs over the years. I have seen faulty injectors or wiring harness fry the PCM, also I've seen a water leak, caused by a spotweld that burned through, drown a PCM, I have even seen a guy who drilled through his PCM trying to mount a waste paper basket in his truck!!
I have seldom seen a PCM fail with out a root cause, I bet I could count on one hand the number of PCMs I have replaced with out finding a root cause. When ever I sent a vehicle out with out finding an external fault I would cross my fingers and pray that, what ever caused the the old PCM to fail didn't cause the new one to fail. (I didn't get paid for comebacks)
If it were me I would remove the PCM make sure the calibration code is visible, and take it to an automotive recycling center (junk yard) and buy a used one, that way if it fries after you install it you are only out $50.00
good luck!