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Fuel Gauge Issues

B

bravenrace

Member
Hi Guys,
Good news! I've been driving my Mustang a lot lately! Bad News - I don't know how much gas I have in the tank!
A couple years ago, after getting it of the garage in the spring, the gauge stopped working correctly. When it's full, it
reads around a half tank on the gauge. When it's empty, it reads about 1/4 tank. To be honest, I haven't even looked
at it yet, but I thought I'd ask here just in case its something common. I don't have any electrical info on this car as far as
schematics or anything, so if you have any ideas, spit 'em out!
Thanks!

As an aside, I entered my Mustang in a local Mustang show this past weekend... And now I'm thinking I may not be the show type...
 
With the symptoms you're describing, it sounds like a leaky float and/or a float lever that is cattywampus.. Time to remove the sending unit and inspect it. It could just need a cleaning of the resistance coil. Cmaya has some threads about how to adjust the lever arm.
 
Yes time to pull the unit. What year are we talking? Have you replaced the sending unit before? If so is the float of plastic or brass?

The goal at this point is to make sure that when you get down to 1/4 tank, it reads that. Thus you will need to plan to install 1/4 tank worth of gas. After you tweak the sending unit and re-install the unit. Thus we need to know what year.

And here I am sitting by the campfire on vacation.....sigh


TapaYakin' from my iPhone
 
Sorry, it's a '65. I've owned it for 15 years and have never worked on the sending unit at all, so I don't know what it is. But given the originality of the car, I would suspect it's original.
Thanks for the information. Sounds like I need to pull it. Good to have a head start on it being that versus the gauge.
 
Does your tank have a drainplug? Draining a tank without one is a bear.


TapaYakin' from my iPhone
 
With the help of Ivanna Pumpalot?

If you pump all the gas out then ypu wont need to worry about gas falling out when ypu remove the sending unit. The opening for the sending unit is a couple inches above the very bottom of the tank. Thus typically there is a gallon+ of gas remaining after someone drains the tank by pulling the sending unit letting the gas dump out into a container.

If your tank Is original, now is the time to get a flashlight and a mirror and crawl underneathe looking into the tank to see how much crud you can spot. Same goes for when you have drained the tank. Inspect the last gallon removed.

Any doubt, replace the tank with a new one tjat has a plug.


TapaYakin' from my iPhone
 
"bravenrace" said:
Or maybe I'll just keep driving it until the engine stops. :steer
Click to expand...
If your name is Mark, that certainly doesn't guarantee that you'll be out of gas.
 
Piggybacking on the thread- my fuel gauge is way too sensitive and bounces around left and right of the accurate setting. When the car is stopped, it settles onto an accurate indication.
Any ideas?
PS- aftermarket gauge stock sender/wiring
 
"gsxrken" said:
Piggybacking on the thread- my fuel gauge is way too sensitive and bounces around left and right of the accurate setting. When the car is stopped, it settles onto an accurate indication.
Any ideas?
PS- aftermarket gauge stock sender/wiring
Click to expand...
A pinched wire that grounds out during vibration or motion would cause this set of symptoms.
 
For what a tank cost, I would recommend a new tank and sending unit. Plus it's easier to install the unit in a tank out of the car.
 
"gsxrken" said:
Piggybacking on the thread- my fuel gauge is way too sensitive and bounces around left and right of the accurate setting. When the car is stopped, it settles onto an accurate indication.
Any ideas?
PS- aftermarket gauge stock sender/wiring
Click to expand...

bad ground or bad sender IMHO
 
My wiring harnesses are <5 years old. I think my sender may be bad. With the car in the air, i have a rattle when I rap the bottom of the fuel tank with the heel of my hand. Even very lightly. It sounds like something is sitting on the bottom of the tank, and that along with the floating needle is enough for me to pull the sender and have a look around. Need to burn off some gas now!
 
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