Fuel gauge


#1

I have 99 Chevy truck and my fuel gauge is vibrating profusely. None of the other gauges are doing this. Is this my sending unit, fuel filter, or fuel pump causing this?


#2

I recommend you first check for a bad connection between the gauge and the sender unit in the tank. A bad connection could be picking up some noise in the circuit. If that checks ok then make sure the regulated power to the gauge is ok. If that is good then I would guess the gauge itself is the trouble.

Another thought is check the ground to the tank and make sure it is clean, making a good bond to chassis ground.


#3

Do I need to drop the tank in order to check any of these problems?


#4

Likely the gage.

Analog gages are “damped” to prevent them from being too responsive to the vibrations of the gas in the tank as felt by the float and exhibiting exactly the symptom you’re describing. Generally this “damping” is built into analog gages as a capacitive/resistive filter or a mechanical damping system.

NOTE: this is a general statement about analog gages subject to erratic signal inputs, including those in automotive applications. It’s been countless years since I’ve researched this in actual automobiles.


#5

Is it vibrating or swinging wildly as you go around curves? If it’s the latter, the baffle in the tank may have disconnected from the inside of the tank.


#6

It is just vibrating. It is not to the point I cannot see how much gas I have.


#7

I’m not sure if you have to drop the tank or not to make the checks.


#8

NO,you do not have to drop the tank,but you need the proper tool,or you can make one,its a variable resitor circuit.

go green,when needed.