53-54 Gas Gauge Sender

[Robert S.]

Should the resistance between the terminal on the sender and ground be the same with the sender in the tank (with gas in it) and out of the tank if the float is in the same relative position? Or, does having the sender submerged
in liquid (gas) reduce the resistance reading? Thanks for you help, Bob

[Roy B.]

Re: 53-54 Gas Gauge Sender

I don't quit know what your asking, but inside the unit is a (wash board ) device . As the float goes up and down wires inside send different resistance to the gage giving you a reading of how much gas is in the tank. If it get dirty you will get a poor reading. if carful you can open it and clean the point that rides on the wires.

[John H.]

Re: 53-54 Gas Gauge Sender

Bob -

Presence/absence of fuel has no influence on the resistance reading.

[Robert S.]

Re: 53-54 Gas Gauge Sender

Roy, thems the one I got. I get a good smooth resistance reading throughout the full range of the float. But, I get a lower resistance reading when the sender is submerged in fuel!? I guess this means the sender housing should be sealed so no fluid/fuel get inside.

Bob

[Robert S.]

Re: 53-54 Gas Gauge Sender

Thanks John, think I have a problem then. I get a lower resistance reading when the sender is submerged in fuel!? Does this mean the sender housing should be sealed so no fluid/fuel get inside.

Bob

[Roy B.]

Re: 53-54 Gas Gauge Sender

No! Don't matter, this resistance reading your talking about? is the fuel gage reading correct ? And if so don't worry

[Mike M.]

Re: 53-54 Gas Gauge Sender

got good ground betwen tank itself and the sending unit? external tooth star washer at ground? mike

[Robert S.]

Re: 53-54 Gas Gauge Sender

Yea, got the star washer. This hole thing started with some erratic gauge readings. I was pretty sure the gauge was good so...I took the sender out of the tank. Then I tested the sender out of the car, both dry and submerged into some fuel, same connections to the ohm meter. When the sender is submerged the resistance reading is lower, as if some fuel is entering the sender and reducing the resistance reading.

If it weren't for the erratic gauge reads I could care less about the difference in readings.

Does anyone know what the resistence readings should be?

Thanks guys!

[Robert S.]

I think I got!

Problem: Fuel gauge erratic when less than a quarter to half a tank. Sender unit out of car measures differeent resistence levels when dry and when submerged in fuel.

Distance from the lip of the tank to bottom, measured at the sender hole, is 7 inches, while the front of the tank entends lower. The sending unit entends into the tank 6 5/8 inches. Thus when the fuel level in the tank is low the sending unit it is not submerged in fuel.

So both Roy and John had it right
- Roy mentioned cleaning the sender.
- John said it shouldn't matter if the sending unit is in the fuel or not.

A dirty sender unit will read higher resistence when dry, giving a false higher fuel gauge reading. When the fuel level is above the sending unit the fuel reduces the resistance so the gauge reads a low fuel quanity level then if the sender were dry.

A clean sending unit should read the same resistence wet or dry, thus allowing the gauge read correctly.

Anyone is a fault in my logic?

[John H.]

Re: 53-54 Gas Gauge Sender

Bob -

Should read zero ohms empty, 30-33 ohms full.

[Robert S.]

Thanks John *NM*