Gas gauge troubleshooting

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Sirsmiley9

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Im not really the best at understanding wiring, but I have a gas gauge which does not work I ordered a fuel sending ground strap, because whoever did it before just put a wire from the corner of the tank to the chassis as the ground, which im not sure if it will work. However, im not sure if it is the voltage limiter is working, because the temperature gauge is moving, but will go up to half when the car turns on but wont go above a quarter when running, so im not sure what I can fix if the wiring in the dash is wrong
 
First we need to know what you are working on, and standard or Ralleye cluster? This is because the IVR is internal to the fuel gauge in those clusters

You need to come up with test resistors, or if you have a variable pot/ rheostat, or an old but workable fuel sender you can use that.

I did not "do" this photo, someone was kind enough to Photoshop the resistances in:

c-3826-jpg-jpg.jpg


The overall path "in general" is ignition switch.........to cluster connector.........to pc board trace.......to IVR......and branch off feeding power to gauges

Each gauge sender stud leads to a board connector pin.......into the harness......and off to the engine (firewall connector) or rear harness (kick panel connector

So you need to test that the connections are good, and don't forget the sender connectors themselves.

If you have a fuel sender you can adjust it to the resistances in the photo, hook it to a sender wire, and each gauge should read as indicated, and both temp and fuel should read the same.

Some of the problems in no particular order:

Wire connections as noted above......

Dirty/ loose PC board harness connector pins

Loose / corroded gauge studs/ nuts

Loose connections between board traces and the IVR connectors......you have to solder bridges across

And of course bad IVR and or bad gauge units
 
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my bad i realize I should have mentioned both of those things its a plymouth duster with standard guage
-edit 1976 duster
 
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You should put year as well. Wiring diagrams are different over the years.
 
SirSmiley, I know you said you may not be good at wiring, but dont be discouraged by all the intel that 67Dart273 offered, he can walk u through it.
He is one of the best on this site.
 
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Several names, it's the regulator device for the gauges. "Instrument voltage regulator" "voltage limiter" and some others. By the way if it's not a solid state replacement, now would be a good time.
 
ohhh ok
I couldnt find it when I was under the gauge cluster yesterday, So I think I will probably have to take it off so I can properly look at everything, which im kind of dreading but thats for tomorrow
 
I wouldn’t get in a big hurry to pull the dash just yet. Do some more troubleshooting. Pulling the dash could create a lot of collateral damage if you don’t do it right. You may well wind up there, but don’t start there.
 
if the water is cold and the temp gauge needle moves at all at switch on... something is wrong. It could be the temp sender but my cases they simply quit working, no needle movement at all.
There is a white plastic engine harness connector under the hood. these will melt down and short wires together. The purple temp sender wire is in this connector.
Wild needle swings is a sign of faulty mechanical limiter. Most often seen at switch on with pre heated water. The added ground wire you describe doesn't always work because the fuel sender is pretty much isolated by its mounting gasket. If the lock ring at sender and the tank hanging straps were a guaranteed low resistance chassis ground path the factory would not have added the ground jumper on the sender.
The possibility exists that a faulty limiter has already killed the fuel gauge. So like others have said, look at other parts of the circuits first, maybe end up in the instrument panel.
 
Just FYI all, the Radio Shack number for a solid state IVR is 2761770. I don't have a number for the heat sink though.
 
If you are not an electronics guy you should just but the plug in replacement IVR.
 
You can still get them on line, I just got one for a buddy's car this week.
 
Speaking of earth at the sender...is a hose clamped wire to the hose spigot acceptable? Mine goes straight to flexible hose from the sender, and Im starting to look why mines not working too...
 
Wagon of Death said:
Speaking of earth at the sender...is a hose clamped wire to the hose spigot acceptable? Mine goes straight to flexible hose from the sender, and Im starting to look why mines not working too...
Click to expand...
The factories ground jumper simply snapped onto the metal fuel lines to create a ground path over the short piece of neoprene fuel line there. Two hose clamps with a piece of wire could be as good as original if hose clamps hold the wire tightly. A length of braided ground strap will fill underneath hose clamps, serve better than small stranded wire.
 
Start by unplugging the temp and fuel sender wires from the senders. Turn the ignition switch to the on position. If you get any movement in the temp or fuel gauge needles, you have more problems than the IVR or sending units. Something in the instrument cluster or wiring. If no movement in the needles, turn the ignition off again, and connect a jumper wire from the temp sender wire conductor to a good ground. turn on the ignition again and check for movement on the temp gauge. If it now moves toward hot (don't let it peg) turn the key back off and do the same test with the fuel sender wire. If the tests don't move the gauges, you have bad senders, a bad IVR, cooked gauges, circuit board problems, or opens in the wiring. If one gauge works and the other doesn't, most likely a bad sender, but, there again, it could be a circuit board problem, cooked gauge, or open wire for that one gauge.
 
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