Fuel gauge limiter

[peterdoherty]

Hello

My fuel gauge does'nt work. So I checked the sender wire at the tank and had no power, checked the connection behind the left kick panel no power. I tried the terminal at the back of the instrument cluster no power. The temp gauge is working so I'm thinking the limiter is fine and the circuit board looks good. Is it possible the temp gauge is getting the pulse from the limiter and the fuel gauge is'nt?

Could the gauge be checked using a 9 volt battery.

Thanks

 

[RedFish]

With OEM mechanical limiter the voltage you were looking for on the sender wire was a low and broken pulse of about 3 volts. You would get a good test from a 12 volt test light. You would need a volt meter.
If you got nothing
The winding inside the fuel gauge may be burned in two or maybe just a bad connection where the gauge is attached to the printed circuit board.

 

[68gtxman]

You're trying to get power from a ground wire??? Remember that the wire to the sender is a ground. Do you have the ground jumper strap installed between the sender and the steel fuel line?

Yes, it is possible for the fuel gauge to not have power while the temperature gauge does, depending on what model car you have. Some models have the voltage limiter installed right in the fuel gauge while others do not.

You'll have to pull the cluster to check out what's really happening.

 

[RedFish]

You're trying to get power from a ground wire??? Remember that the wire to the sender is a ground.

The reduced gauge voltage can be seen on the sender wires. If you don't agree, the wire on your temp sender is easy enough to access. Prove me wrong.

 

[Inertia]

I've had several vehicles where the 2 nut/bolts holding the guage to the circuit board were corroded.. I disconnected battery, and got in behind with a small wrench,, and worked the two nuts back and forth,, then snugged em down,, solved the prob..

As mentioned,, it's a slow intermittant pulse of electricity to the tank..

Also mentioned is that little metal ground strap bridging the rubber hose at the tank, that's the ground..

 

[Inertia]

You're trying to get power from a ground wire??? Remember that the wire to the sender is a ground. Do you have the ground jumper strap installed between the sender and the steel fuel line?QUOTE]


It's a live wire till it contacts a ground..

 

[67Dart273]

The winding inside the fuel gauge may be burned in two or maybe just a bad connection where the gauge is attached to the printed circuit board.

the 2 nut/bolts holding the guage to the circuit board were corroded..

^^ THE ABOVE ^^

I've preached and preached this. Think of the gauges as "an end to end system."

That means all the way from one battery post, in the long circuitous path back to the other battery post, all the wiring, connections, components in between. EVERY single one

The list of "what was wrong" on my 67 is lengthy. ALL of this was "wrong" and "each" one would have rendered the gauges inoperative:

1....On a side note, due to "the usual suspects" there was voltage drop in the bulkhead / ignition circuit. READ

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

2....The pins on the (two) PC boards connectors were loose and broken

3....The limiter SOCKET in the board....springy contacts which are pressed into the board....were not making contact with the board traces.....I soldered jumpers across

4....The limiter was bad

5....THE NUTS ON THE GAUGE STUDS were corroded and NOT MAKING CONTACT between the gauge studs and the gauges.

NOT a factor in my car, but possibilities in other cars:

6.....Any bad connection in the sender circuit, IE in the bulkhead or kick panel, or the sender end connector itself

7.....Obviously, a bad sender. Corroded, sticking, sunk float, physical damage due to collision, on and on

8.....Improperly or poorly grounded sender due to corrosion at the tank to body

9....A bad / worn out / sticky / burned up gauge unit. Let's not forget how old these are, and the environments some of them "have been through".......very hot unrelenting AZ and TX and CA sun, or sub freezing temperatures, or saturated humidity and rust, corrosion OR ALL OF THESE for the last 45 years!!! LOL

 

[peterdoherty]

I checked the gauge with a voltmeter and had 3 volts supplied from the limiter. I grounded the sender side, turned the key on and the needle never moved. So it's definitely the fuel gauge itself.

Thanks to everyone for their responses.

Peter

Now I need a fuel gauge.