Fuel Gauge always Full

[wolf39us]

My 87 GT fuel gauge is always full up until about 1/8 of a tank (when the gas light goes on)...am I safe to assume just replace the sending unit....??

also I have another question.. since if I replace the sending unit the tank has to be dropped...is it really worth it to change out the fuel pump (mine is stock) and if so what liters per hour is best?

 

[dcurtis]

Yeah your problem is most likely the sending unit, (I have the same problem right now) and if you have any mods or plan on some mods a differant pump would be a smart thing to do while you are in there. My car is stock engine wise and as soon as I find a sending unit I will be putting a 190lph pump in there with it. The added fuel will be fine since it is regulated any way. And if you do have prob's you can always throw an aftermarket pressure regulator on there, holley makes one for around 40 bucks that mounts in the stock position.

 

[jrichker]

I have the same problem. The gauge reads off scale full until there is about 2 gallons of fuel left. I would suspect the anti-slosh module that is mounted on the back of the instrument panel is the cause of the problem.

 

[wolf39us]

yeah...but so many people say the sending unit...and then there are a few who say this anti-slosh unit...is there a way to figure out which without replacing stuff left and right?

 

[dcurtis]

I have never even heard of the anti slosh module before, my guage reads past full no matter how much gas is in it, where do you get a anti slosh module, and what is it? My guage was reading perfect until one day I had the tank on Empty so I put maybe 3 gallons in it just to get me home and the guage has been full ever since.

 

[LiquidGT]

IDK if its true, but I heard you can plug the harness for the sending unit in backwards on the tank and it makes the gauge act that way. I havent changed my fuel pump yet so I have yet to see for myself.

I'll have a half tank of gas (7.7gal) when my gauge reads at the mark below half tank. I even changed the module and I ended up out of gas at two marks below half a tank, so I went back to the original module.

 

[LiquidGT]

This is the anti slosh module on the back of the cluster.

I seen them at 50resto and at the junk yard of course.

 

[wolf39us]

whats it's purpose? lol

 

[HISSIN50]

whats it's purpose? lol

It introduces hysteresis into the needle-reading so the gauge's needle doesn't fly around every time the gas sloshes (and the float level changes).

 

[wolf39us]

ok but if that went bad then I should probably either get no reading at all, or a crazy fuel gauge...

come to think of it actually...when I fill up my tank....my fuel gauge spins in circles...it's actually quite amusing