Fuel gauge

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Wrencher

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Is it safe to rule out a bad cluster voltage regulator if the temperature gauge is working?

Im pretty sure I can call it a bad sending unit, just felt i would double check.
 
Yes. The one limiter supplies low voltage to both gauges.
 
Check the sending unit ground jumper strap before you replace the sending unit. This strap gets the ground to the sending unit circuit through the sending unit and then up to the gauge.
 
Could still be the gauge itself. I'd run through the tests on it. Is it reading at all? High? Low? Bouncing?
 
had that happen on my 75 scamp i drove for a while.
we still had one of the old gage testers here.check with some local shops maybe someone still has one.
you hook it up at tank and adjust dial and watch gage.mine worked fine.
pulled sender to put a new float and sock on it anyway.
resistance checked good.
was bad ground.soldered a piece of 10-12 ga wire to feed pipe and bolted other end to body.worked like a charm
 
The gauge doesn't read at all. What I have done so far is. With the key in the run position and the engine not running, I disconnected the wire from the sender and grounded it. The gauged moved promptly toward full, and dropped back down when I removed it. So I figure the wire and the gauge are likely good to go.
 
My fuel gauge works but not my temp gauge??? I did replace the sensor on the head but still no luck...Any suggestions??
 
Sure, I would ground the wire and see if the gauge moves, I'm pretty sure that it can be tested the same way as the fuel gauge.
 
Plyscamp -

Disconnect the temp sending unit, and then put it's wire to a source of ground (key on, engine off). Have someone watch the gauge. If the wire and gauge is good, then the gauge will sweep one way when you ground it, and sweep in the other direction when you unground.

If it sweeps when you do this test, then i would suggest looking at the ground wire from the engine to firewall. possible ground issue perhaps? Of course, this is assuming that the parts house gave you the correct sending unit for your application.

No sweep from that test? time to grab the fluke meter and ohm out the wire, and be sure that you have continuity from the bulkhead to the sending unit. If so move inside the car and check the wire again from the bulkhead to the Cluster. If you have continuity, your wiring is good and the problem is likely to be the gauge. This is where the water gets muddy for me because I really wouldn't know how to test it, nor what to look for grounding wise. I would GUESS that it take its ground right off the cluster voltage regulator

I'd be willing to bet that someone with more specific experience on THESE cars will chime in with a more likely suspect to check out in your situation. I dont really have access to wiring diagrams or anything of the sort
 
There are 4 types of sender, one for a gauge, one for a warning lamp, and one each of China made crap.
I suppose it is possible to wrap so much teflon tape around the senders threads that it would be isolated from chassis gorund.
The sender is the only ground path though. The gauge itself is isolated from chassis ground in the instrument panel.
At first glance the gauge will look as if it is mounted to and contacting the metal housing. The housing is cut away behind the gauge can so the gauge contacts only the circuit board.
 
Does anybody have a picture of the ground strap on the fuel sender, I'm having a problem also, ground my wire at the tank the gauge on dash works. My sending unit is only a few years old.

Which pisses me off, but that's the berries.
 
I dont have a pic of it but its just a clip on steel tingy that carries the ground path over the rubber hose at the sender. If yours is missing you can make one with a short piece of wire and 2 gear screw clamps.
If yours was working the strap was there. Maybe its still there and just needs cleaner contact points.
There are some poorly built senders with plastic floats out there too.
If a saturated float is the problem the gauge pointer should still climb from its home position to the empty mark at switch on.
 
The ground jumper strap connects the fuel line from the sender to the steel fuel line going up to the fuel pump. It is about 4" long and bridges the short rubber fuel line between the sender's fuel line and the steel fuel line to the fuel pump.
 
I bought a aftermarket ground strap for my '65 and it broke when I tried to snap it on!!!! so I took a piece of wire and a couple of hose clamps and hooked the wire to the sending unit fuel line nipple and the other end to the steel line fuel line. gauge has been working great for almost a year now!!!
 
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