Re: Ford F-150 questions

LOL

The short is between the switch and the gauge unless both sending units are shorted Check the valve that switches the tanks and the switch on the dash---the gauge could be wired to either---have to get a wiring diagram or trace the wire to tell

Put a quart of carb cleaner in the bad tank and drive it on the good tank for a couple days then drop it and dump it replace all ruber fuel lines on both tanks while you are under there---better under controlled conditions than on the roadside somewhere

The problem will LIKELY be in the tank selector switch. The wire from the guage unit to the selector switch is being grounded SOMEWHERE. Disconnect the wire on the selector and youwill LIKELY get the guage to drop. A spdt switch between the 2 tankj senders and the guage unit will then make it work - independently of the tank switch.

Except yhou need to remember - your Caravan does NOT have either upper control arms OR upper ball joints.

Wieber has said many times that he has electronics skills, and owns several oscilloscopes. For example: "my electronics shop"

Why would you be giving basic troubleshooting advice to a guy who claims to have an "electronics shop?" Are you thinking there's some planet where electronic techs need basic advice on how to fix a fuel gauge? LOL

I know a lot of electronic technitians and even engineers who would not have a clue what to look for on an automotive fuel guage - muchless on a dual tank system.

Also, the tools most definitely do not make the man - or the technitian - even if you know how to use the tools.

Fortunatrely I've had a lot of experience inthese things, and I'm willing to share my knowlege.

Unlike somany who know nothing and are more than willing to share THAT.

LOL!

Wieber never learns. Wieber *can't* learn.

Like Wieber.

Yes.

I relied on the schematic in the factory shop manual when my Ford's pump and sender unit malfunctioned. It showed what to look for and where to access the signals in the wiring harness.

-jsw

Techs who claim to charge $75 an hour to troubleshoot and repair machine controls, but who don't know how to read a fuel gauge wiring diagram? Riiiight.

Exactly.

No. If he knew how to use an oscilloscope, then he'd know how to troubleshoot by read a wiring diagram.

But he doesn't. And here's proof, an independent review of his electrical troubleshooting skills.

There can be no doubt - Wieber is allergic to common sense and wiring diagrams.

Oh sure, I can build a plane, but can't fix a fuel gauge. That makes sense to you? Of course it does. Get a clue. I don't help liars. Especially deadbeat liars. Doubly especially liars who espouse hanging people from lamp posts. If only I had the kind of "Christian" sensibility that allowed me to be OK with hanging millions, eh? Wieber deserves mocking, not help. The best part is that he's more likely to claim to have a fuel gauge repair business than he is to ever fix that gauge. At least we're all the wiser for learning how to use PB Blaster to fix electrical problems.

Hey, it's only been seven years since it was proven that "tech" Wieber doesn't know what to do with a wiring diagram.

Check the charging system. On some of the old EEC IV systems the check engine will come on with bad charging system.

Could also be a bad ground wire (had that happenon Pontiac TranSport.

The original fuel sender from my 91 Ranger measures 15.0 Ohms empty and 168 Ohms full. The float is plastic. The replacement cost $82.99 at Autozone.

Pull the red tab out of connectors with needlenose pliers to free the pins to pull out the back through the silicone rubber. Autozone sells Ford pin replacements.

In my experience circuits are much more likely to be open than shorted.

The bed bolts are T55 Torx and there's a taillight connector behind the bumper and the fuel filler screws to undo before lifting the bed off. I place a wood spacer behind the cab to protect the paint. It's an easy one-man job with an engine hoist and a 2x6 cut to fit under the top rails of the bed.

-jsw

Disconnect the yellow and white wire from the switch - see what happens. Then ground the yellow and white wire and see what happens. On a lot of the later Ford products the guage works backwards from a Chevy and most others.

Your Ford may well have a guage system that reads full when the sender is OPEN and empty when it is GROUNDED.

Thiswould make sense on your truck, having sat for so many years - the very low current through the switch to the senders, and possibly the contacts on the fuel sender units, are oxidized enough that NO current gets through and the guage stays pinned on full.

From Advance AutoParts.com:

To test the fuel sending unit, you will need to fill the tank with gas. Use a multimeter to test resistance. In an old-school classic with analog gauges, you'll need to know how the gauge works, as manufacturers used different electrical conductance to operate the gauge. For example, a Ford fuel sending unit has almost zero resistance on a full tank, while a GM sending unit of the same year has maximum resistance on a full tank. Your repair manual will advise you here.

If the resistance reading is off by several ohms, you have found the culprit. Before yanking out the fuel sending unit, go the affordable route with a bottle of fuel system cleaner. While there are no miracles in a bottle, car forums are littered with posts explaining how an $8 bottle fixed their fuel gauge/sending unit problem. The float on the sending unit may have become corroded with sulfur from low grade fuel, and there is a possibility the fuel system cleaner may resolve the issue. GM technical service bulletin #06-00-89-07BB specifically states to use fuel system cleaner to resolve a stuck sending unit.

Coach battery

The EGR position sensor on an '88 Ford will cause that problem, and being "OBD1" - or technically EEC IV, it will not necessarily throw or hold a code..

Check the connections on the EGR - also check to be ABSOLUTELY CERTAIN there are no vacuum leaks in the EGR control system. Perhaps remove the EGR valve and clean the heck out of it. The postion sensor may be mis-reading the position, or the valve may actually be sticking

Put your 'scope on the alternator output and check to be sure the output is constant. NOT LIKELY, but possibly the brushes are jumping and the charge is intermittent - which on SOME vehicles will screw with the CEL.

I have a code reader that plugs into the test connector behind the engine fuse box, but there's a way to view the EEC-IV codes without one, by counting CEL flashes.

-jsw

That is true up until 1986. From then on, Ford works backwards.

Tank empty should be ~22.5 Ohms. Tank full should be ~145 Ohms.

My "Auto X-Ray" unit pulls power from the plug on EEC IV systems.

Owatona units do not.

Don't know about the Snap-Off stuff.

That's because they are "ford lovers" - they haven't had to workon the beasts!!!

That said, I'm on Fords 5 and 6 right now. #1 was a 1976? Granada Ghia. Then I had an '89 and a '90 Aerostar, and a 1995 Mystique (Mondeo). Other than rust and a few electical problems on the Mystique (due to it's British DNA) I was pretty happy with them.

Currerntly a 2002 Taurus and a '96 Ranger.