Possible ground wire issue or Sending Unit

[oldchevelle541]

Today we took the car out for a brief cruise and saw that every now and then the gas gauge would go from 3/4 tank to Empty and sit there. Then after a few stops and starts it would go back to 3/4 tank again. We had the car for 10 years and never has the gauge every gave us an issue. The gauge has been accurate as far as provding the correct fuel level in the tank. Before I start poking around just curious if anyone has every experienced this. When we got home we washed the car and started it to put it back in the garage and gauge was fine.

 

[snakeoil24]

You have a jumper that goes from metal fuel linewhich jumps over the rubber fuel line to the metal sending unit for grounding. Approximately 3 inches see if it is corroded

 

[Paul_B]

I’d check the ground strap that snakeoil mentioned. I have even replaced this ground strap with a piece of copper wire and a couple of small hose clamps on some cars.

 

[Don Frelier]

Another thing you can do is loosen the connections on the gauge and clean them then reconnect.

 

[khryslerkid]

 

[kiwigtx]

It is entirely possible that if you have a brass float on the sender unit....there will be a pinhole in the float.
This will cause the float to fill up with fuel and sink or bob around all over the place.

I had this many years ago, so I know it happens.

 

[Don Frelier]

It is entirely possible that if you have a brass float on the sender unit....there will be a pinhole in the float.
This will cause the float to fill up with fuel and sink or bob around all over the place.

I had this many years ago, so I know it happens.

If it fills it's going to sink ( read low or empty)
I don't see how the reading will come and go in that circumstance.

 

[kiwigtx]

If it fills it's going to sink ( read low or empty)
I don't see how the reading will come and go in that circumstance.

Half full the sender will ride the wave of fuel when the car is in motion.....or pulling up to a stop.

 

[multimopes]

I actually had this happen on my old A-100! It was just like Roger said!

 

[kiwigtx]

I actually had this happen on my old A-100! It was just like Roger said!

Thanks Brian.

 

[oldchevelle541]

To all, thanks for the quick reply and comments. I will first check all connections, rust, loose, etc. If sending unit is going bad I will have it restored. Years back I had a Coronet and purchased a new sending unit and the old girl and wiring did not like new. It simply did not work. Sent the original out to a company in Ohio to restore it and when reinstalled I was back in business.

 

[matthon]

The ground strap is a pain, dealing with one now. Replaced it, worked for a minute.

 

[kiwigtx]

The ground strap is a pain, dealing with one now. Replaced it, worked for a minute.

The 'push-on' ground strap is a very poor design in electrical terms.

I used hose clamps and proper electrical connectors clamped firmly under said clamps.