[vern]

i have 2 tanks and they both read the same way. it will read full till it gets to be about a 1/4 tank then seems to be right. i think? i usually go to the other tank when that happens. but i woul really like to know what else to check. could it be the ground on the guage it self? or could it be a faulty guage? <img src="confused.gif" border="0">

[dmorris1200]

Without knowing what type and year of truck I will just say that usually checking this type of concern requires dropping the gas tank and checking the sender with an ohmmeter while sweeping the float. Then we would install a gauge tester (basically a fancy potentiameter) to the gauge harness and then set it for specific resistances (figures found in service manuals) and watch for specific gauge readings. Now the float/sender you could probably check with a simple digital ohmmeter after removing from gas tank. If you get the specific resistances needed for checking proper gauge sweep you could probably make something from your local radio shack to duplicate the resistances needed. You are definately going to want a service manual for the vehicle. Good luck.

[adtkart]

If it always reads that way, I would try filling the tank only half way once to see how it reads. It may be that the float is sticking at the top. Seen that happen before. Have had sending units that were removed or replaced that were bent when or before they were put in. They stuck, sometimes in the upper positions, sometimes in the lower positions. They have to move freely to work right.

[vern]

once it gets to a 1/4 tank it will read right. its in a 1988 ford f150 what confuses me is it is that way in both tanks

[trees]

I would check the grounds on the tanks first thing since the sending unit works on the principal of increasing/decreasing the amount of resistance going to ground. The next step would be to ensure the correct resistantce wire is used from the guage to the sending unit. If its stock should not be a problem other than corrosion in any plug in connecters. Corrosion on grounds or connectors can become an electrical nightmare.

Trees