Fuel gauge goes all over the place. 1970 Dodge Charger

[Dominic Torreto]

FUEL gauge will litterly show its over half a tank and or 3/4.After a little bit of time it shows way under Empty? Brand new sending unit and I already checked wires. Anybody ever had this happen? Could this be the IVR in dash being out?

 

[pnora]

 

[66383]

What car, fuel tank new or old, sending unit new or old? Is it grounded properly?

 

[sam dupont]

Model and year? Some have a CVR, Constant Voltage Regulator. They are a points contact and can go bad

 

[kiwigtx]

Mine usually goes hard to the left under full acceleration.

Many things to check.....please supply more info on exactly what gauge, car, year, tank.....etc pictures are worth a thousand words.

 

[AR67GTX]

This gauge will litterly show its ober half a tank and or 3/4 after a little bit of time it shows way under Empty? Brand new sebding ubit and I already checked wires. Anybody ever had this happen? Could this be the IVR in dash being out?

Yes - but usually the temperature gauge will also act the same way.

 

[kiwigtx]

P

Where.....in the carburettor? The man from AAA advised against that last time.

 

[AR67GTX]

Man - you’re too fast on the draw. I can’t hit edit to fix my fat fingered typo/post reply that fast.

 

[MarPar]

Where.....in the carburettor? The man from AAA advised against that last time.

 

[Dominic Torreto]

What car, fuel tank new or old, sending unit new or old? Is it grounded properly?

1970 Dodge Charger 440

 

[kiwigtx]

1970 Dodge Charger 440

Check the ground strap between the tank sender and the fuel line underneath the car - the strap may be loose, or covered in underseal or some other debris. They get weak and fall off sometimes.

 

[Dominic Torreto]

What car, fuel tank new or old, sending unit new or old? Is it grounded properly

Brand new fuel sending unit and an old stock gauge.

 

[kiwigtx]

....and have a look at the blue wire on the inside of the trunk floor.....you might have something rolling around and damaging the wire.

Or the jack being cinched down might have pinched the wire.

 

[kiwigtx]

Brand new fuel sending unit and an old stock gauge.

People need to learn that New doesn't always equal Good.

 

[Dominic Torreto]

Check the ground strap between the tank sender and the fuel line underneath the car - the strap may be loose, or covered in underseal or some other debris. They get weak and fall off sometimes.

Thats not a bad idea man. I will definitely look into that one because I did paint the fuel tank. Is it possible to add a ground wire? Dont

 

[kiwigtx]

Thats not a bad idea man. I will definitely look into that one because I did paint the fuel tank. Is it possible to add a ground wire? Dont

Yes, you can add a ground wire anywhere on the car......just be sure to clean both surfaces under the clamp or however you intend to attach the ground wire terminal. Clean steel both ends will give a good result - use some di-electric or silicone grease to protect afterwards once you have proven it's effectiveness.

 

[kiwigtx]

I will definitely look into that one because I did paint the fuel tank.

Ground continuity is made between the fuel line and the sender unit base plate......not the tank as such.

Ground straps as OE connect onto the stub of solid line exiting the baseplate.

 

[Dominic Torreto]

I just did some tests the tanks ground is good. Gonna just by the cvr and tell you guys what happens

 

[sam dupont]

I have learned a little about CVRs recently with my Scout 800. I have to admit I didn't check the sending unit plug to my temp gauge and the tanks haven't been used in 30 years, but I found a nearly non-existent CVR for only $33 delivered, so I bought it. I'll change it out regardless as when they go bad it can be bad.

 

[Dominic Torreto]

I have learned a little about CVRs recently with my Scout 800. I have to admit I didn't check the sending unit plug to my temp gauge and the tanks haven't been used in 30 years, but I found a nearly non-existent CVR for only $33 delivered, so I bought it. I'll change it out regardless as when they go bad it can be bad.


View attachment 1584840

What was your gauge doing if I may ask?