I have a '60 F100 with an original electric fuel gauge. When I first got the truck I took the tank out and had it boiled, I also bought a new 'vintique' sending unit. Ever since then I have had a reoccurring issue where the fuel gauge will work just fine, and then out of nowhere hits zero. Then randomly a day or two later it will work just fine again. I used a test light and I could see that I have power (flashing light) to the unit and it is grounded to the cab. I grounded out the wire coming into the sending unit as well and it made the gauge show Full. My understanding is that means the gauge is good, right? What makes it even weird is this, when I hook up my test light to the stud on top of the sending unit and the light starts flashing, I can see that the gauge slowly starts to creep up instead of sitting at Zero. And when I remove the test light the gauge goes back to zero. I am really scratching my head here. Any suggestions? I tried taking the unit back once but was told that it would be held for 'testing' for a week before I could get a replacement and I couldn't be without my truck for a week. My other gauges/dummy lights work fine.
That is what I keep thinking, but I have fiddle with the ground wire until I'm blue in the face. Unless the cab isn't grounding. My next thought was to ground the cab to the frame with a bolt and then connect that spot to the negative side of the battery.
No ground wires on the gauges I'm pretty sure, similar to the lights. Those grounded through the housing.
Have you jumpered the sender to ground and left everything hooked. Ground a mounting screw to the frame using a wire with gator clips on it. See if anything changes. Sounds like ground are lack of. Sending units are cheap made. Make sure the terminal on the sender wire is god wires not broken. same on the ground wire if it has one.
That is what should happen. Your test light bulb filiment is acting like a resistor tied to ground. So, you are actually grounding out the top of the sender. If you suspect a bad ground or the company does, then take a few minutes to run a wire up from the chassis to the screws on the sender. If the gauge still acts up like before, it sounds like a intermittant contact in the sender. Ahh So, "hecho 'en ___" (some half assed plant somehere on the planet.) Not that brand, but I tried to install one on a 50 shoe that the car owner got from a well known place, and it fell apart before I could install it. If everyone stopped buying repro stuff, maybe they'd improve things. That won't happen, so keep posting the bad brands by name. These posts will show on google searches, and potential buyers will go somewhere else?
I didnt have any alligator clips but I ran a wire from the sending unit back to the negative cable on the battery with no change. If I had an intermittent contact in the sender, shouldn't I be able to pick that up with a multimeter?
A political answer; Yes, and No. A bad connection sometimes will only "act up" with some sort of load on it. Like a taillight bulb. You turn on the switch and get no light or dim light. Then unhook the wire, and test with a meter and it shows continuity. This could be why you can't pick it up, especially with a digital. Analog might. What I'd do is take it out to see if you can remove the tin cover from the guts of the sender. Sometimes just tabs bent over. (sometimes, sealed plastic that will be difficult) Inside you will see a wiper conact that runs across the fine wire wrapped coil. The wiper arm that holds the contact points, could be bent, or too weak to hold it against the windings...or pehaps the windings are not laying flat enough.?
Opened up my sending unit and everything appears to be fine. I can even hear the arm dragging across the wires. The only other weird thing I can think of is that the gauge is usually below empty when off and when on it raises to 0 and stops.
What I would do, now that the sender is out: Run the wires to it, including a good ground. Now try every possible position on the sender float to get it to act up? Let it sit in each spot for more that a few seconds. Maybe it's just one spot on the wrapped wire, or maybe there is a poor solder joint on the sender wiring. Cold soldering was a problem on the one repro I had that fell apart.
On my 60' there was a small ground strap that went from one of the screws on the sending unit up to a screw in the cab. If I remember later, I'll head out and see if I can get a pic of the wire (tank is out of the truck right now). From what you described, it sounds like the gauge is good. The sending unit can be checked by hooking up your multimeter to the sending unit and measuring resistance while you move the float through its range of motion. I can't remember off the top of my head what the readings should be. Can probably find them on line. Best of luck.
I tried that last night, I did notice that if I moved the arm only slightly (like only a few gallons) that the gauge didnt move. But if I moved the arm to half full the gauge went to half full. I'll try bending the arm a little straighter and see if it helps. Maybe Vintique just makes p.o.s. sending units.
No problem. If you want, later I'll head out after it stops raining and pull my sending unit and check its resistance through its range of motion.
that would be cool, then I could check if mine matches. So far I'm only good with a multimeter checking continuity!
dude just drive it when it works ... thumb it on the other days .. happy 4th . hope youu fix it soon . o-jake .
hahaha. With gas where it is now I can barely drive this thing as is. Which sucks, because I always told myself if I had a good running older vehicle I'd drive it everyday.
You said original electric guage,does your sending unit have the right ohms to match the guage. Went through the same crap with some autometer sending units.
Mine shows about 87-89 ohms empty and 30-32 full. Hope this helps. I 'assume' this sending unit is good. It was difficult getting good connections! Jeff
When you check resistance, do you do it with the unit out of the car? I check it using the 200 setting and it appeared to be 75 empty and 10-11 full.
Maybe someone will chime in with the correct ohms for the 60 Ford. Sounds kinda high for stock. On my 60 Chevy its 0 empty 30 full.
looks like it is supposed to be [FONT=Verdana, Arial, Helvetica, sans-serif]8-12 ohms full and 70-73 ohms empty, i found that on another website [/FONT]
I don't know the specs for your 60 Ford, but I have been reading up on an older tech thread by Kevinsrodshop on hamb. He did a tech on how to use 70s Ford pickup gauge guts into older car gauge faces to make them modern functioning. Kevin said that these years Ford gauges, no matter if oil , fuel or temp, are rated at 30 ohm at "half scale". I don't believe he said if there were low and high end specs, but maybe take a look there. He said these gauges have a high end and low end adjuster, to get it to read right at low or high. I do have those gauges now, and I see the adjusters. So, from what he said, I would see if you have around 30 at 1/2 throw on the float. That may not be the same as a 60 Ford was, but at least a start? I am pretty sure GM trucks were called "90 ohm" from memory EDIT: I see you just found the correct 60 specs..
Well, I tried adjusting the arm last night to be straighter and bring the float up higher, and it made no difference whatsoever. Really don't know what's going on with this unit.
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