Gas gauge quit working? Help

[Tony formula s]

1965 Barracuda formula s new tank and sending unit new rear wiring, harness gas gauge worked fine, now it’s not, installed ground strap on gas tank tube that jumps the rubber portion of the tube still no gas gauge worries me because it did work before any suggestions guys and gals

 

[TrailBeast]

1965 Barracuda formula s new tank and sending unit new rear wiring, harness gas gauge worked fine, now it’s not, installed ground strap on gas tank tube that jumps the rubber portion of the tube still no gas gauge worries me because it did work before any suggestions guys and gals

Ground the sender wire at the tank and see if the gauge shows full.
If it doesn’t, something about the gauge or wire from the tank to the gauge is faulty.

If it does show full when the wire is grounded, then it’s likely the sender.

 

[Tony formula s]

Ground the sender wire at the tank and see if the gauge shows full.
If it doesn’t, something about the gauge or wire from the tank to the gauge is faulty.

If it does show full when the wire is grounded, then it’s likely the sender.

Thank you sir great advice I will check it out Thank you for the time.

 

[Dana67Dart]

Does the temp gauge work?

 

[Tony formula s]

Does the temp gauge work?

Yes sir …?

 

[Dana67Dart]

That rules out the IVR so either the gauge itself is faulty, or the nuts on the back of the gauge, or the cir board or the pins on the cir board, or the wiring from the tank to the gauge

As stated earlier you can TEMPORARILY ( like for a few seconds) ground the wire at the tank and you should see the gauge head toward full.

 

[Mattax]

Better would be to connect the sending unit wire to one side of a resistor. Ground the othe side of the resistor.
10 to 75 ohms will work. around 23 ohms should get the gage to indicate half full.

Its better to use a resistor because direct grounding can quickly burn out the gage.

 

[Tony formula s]

Better would be to connect the sending unit wire to one side of a resistor. Ground the othe side of the resistor.
10 to 75 ohms will work. around 23 ohms should get the gage to indicate half full.

Its better to use a resistor because direct grounding can quickly burn out the gage.

Thank you for explaining how to diagnose. I am a HVAC tech working overtime on call but as soon as I have time, I will do this test. Thank you so much.

 

[67Dart273]

Thank you for explaining how to diagnose. I am a HVAC tech working overtime on call but as soon as I have time, I will do this test. Thank you so much.

There has been hundreds of posts on this subject here. If you don't have one, download the closest you can find for a factory service manual, from MyMopar.com. You may have to settle for Plymouth vs Dodge. Treat the problem as an end to end system

Do both gauges, temp and fuel work? If not the problem is likely upstream from the gauges, AKA supply voltage to or the instrument voltage regulator/ limiter.

These are the values for the test resistors:

 

[67Dart273]

Forgot to mention, check the sender ground. Set your multimeter up for lowest resistance scale, and stab hold the probes together HARD. This will give you the shorted probes resistance, which on an accurate meter will be a few tenths of an ohm, showing the probes/ leads/ resistance. Now stab one probe hard into the actual sender metal, not the tank, and stab the other probe hard to get a BODY ground. Should be very close to the previous reading, close to zero