Fuel Gage installation

[LupusKout]

I bought my '75 SII in November without the fuel gage working. I removed the gages from the dash and couldn't locate the sensor line that should be running to the gage. How hard would it be to find one?

[baldscout]

If you unplugged any wiring in the rear, you unplugged the sender wire. It is circuit #36. If your other gauges are working, then you have a bad wire & a fun time to hunt it down; if none of the other gauges are working, then the problem is the CVR; which is one common problem. They do burn out over the years.

Do a search for Electronic CVR or CVR Replacement in Google. Links to IH Only North and Binder Planet are good places to start, as is the Just IH forums.

Other reasons for it to not work is a bad ground at the tank sending unit (also VERY common), a stuck sending unit (easy fix) or a bad gauge.

If you want to replace with an aftermarket, get a Chevrolet / early Ford that has the proper 73 - 10 Ohm range. The proper part number is posted over on binder planet.

[baldscout]

Fuel gauge, what's that ? :confused:
Gallons/mpg on the odometer. :)

Odometer, don't have one. Speedo broke... Use a GPS when it's above +32*F; doesn't work too well when plowing anyway... Gas gauge has been replaced, but I personally have a bad float... Not going to drop the tank when it's -3*F... :eek:

The OP should be able to get things running with some diagnostics...

[baldscout]

Ohms and meters are over and above this shade tree mechanic's expertise, fortunately, my swing away spare tire carrier has a 5 gallon gas can which comes in handy. :o

I have experience in the diagnosis and have the proper tools for it. Not my day job though, nor do I want it to be.

I do carry 5 gallons on the flatbed, nothing like having some spare fuel around.

[LupusKout]

ok... All my gauges except the gas gage works. I know there is an unplugged connection below my gas tank, but looks to be broken. Not sure if that is my line, but does anyojne know whether there is supposed to be a wiring setup on the back of the original gas gauge? It has two screws and nuts like there is but I'm not for certain.

[baldscout]

ok... All my gauges except the gas gage works. I know there is an unplugged connection below my gas tank, but looks to be broken. Not sure if that is my line, but does anyojne know whether there is supposed to be a wiring setup on the back of the original gas gauge? It has two screws and nuts like there is but I'm not for certain.

The gas gauge is connected to the assembly housing with the smaller screws / nuts. The larger nuts are for the Ammeter and get connected to the wiring harness and allow the ammeter to read properly. I would recommend you shunt or bypass / remove that thing, there has been a history of them starting fires (I've had one myself). The gauge is connected to the wiring harness with the plug that you pulled to remove it from the dash.

As for the loose wire at the gas tank, it is either your sending wire or the ground that is broke. Since they only put the circuit number on the ends of the run, it will be hard to trace unless you do a continuity check between the gauge plug and the wire end.

HTH

[Allan E.]

If you ground the sending unit wire, the gauge will read past full, assuming the gauge itself is working.

You can tell if you have the correct wire with a simple test light. Ground the clip of the test light. With the key on, put the probe side to the wire you think is the sending unit wire. You will read the pulsing of the instrument regulator through the wire as the light flashes.

No, you won't burn it out. Just don't leave the fuel gauge pegged for more than a few minutes. It normally has a little resistance in the circuit to keep that from happening.

[LupusKout]

Thanks for the help, but just one more thing. Would it be a bad Idea to bypass the black connector at the gas tank and just have a straight wiring instead?

[baldscout]

Thanks for the help, but just one more thing. Would it be a bad Idea to bypass the black connector at the gas tank and just have a straight wiring instead?

I would say that you would remove any chance of a short or other wiring issue that could crop up. I have a straight wire to the new guage I put in and another going to a good ground. Then again, since it's a flatbed, I have fairly easy access. I removed all of the wiring issues that the PO put into the rear of my rig when I replaced the bed last summer.

I'd say to feel free to remove that connector, you'll probably increase the reliability of the system.

[LupusKout]

That is just the kind of think I like to hear.:D Thanks man

[jlrubicon]

I too have dead fuel gauge (but others work fine). You mention 'stuck' sending unit as 'easy fix' --- would you help me along here? thanks

[baldscout]

I too have dead fuel gauge (but others work fine). You mention 'stuck' sending unit as 'easy fix' --- would you help me along here? thanks

It is an 'easy fix' for anyone who wants to play with the fuel tank. If you have access to the top of the tank, you don't have to drop it.

What you want to do is to pull the sending unit assembly out of the tank and replace the float. The floats are about $6 each at the ford dealership and are brass. I ended up getting two when I ordered mine as it was a special order locally. The part number that you need to order is floating around on the boards. I don't have it in front of me, sorry.

The top of the tank connection should be a rotating lock ring with an o-ring type gasket. You'll want to replace that gasket once you have it pulled. Put in a new float and reassemble. Your done.

Should take a couple hours if you have all the parts ready to go when you start. Remember to have the tank near empty or you'll have a bugger of a time dropping it.