gas guage questions

[do-over]

so i have a 2nd gen and a first gen and the first gen is a 84 s15. about 2 weeks ago i filled up with gas and the gauge has been on full the whole time. and yes i have driven it. any ideas what could be the problem, and where and how to fix? any help would be great. the truck is an 84 4x4 auto with the 2.8 v6 thanks

[MadMikeZ28]

sender gone bad. Signal wire shorted to ground some where. Very good gas milealeg.

[got_u_sick]

Haha, mines the opposite. Sits on E constantly. I got in it one day and it was like that. I just pulled the gauge and cleaned the contacts and stuff, and checked the wires. The gauge drops on its own, but won't go up. Probably my sending unit.

[phaderus]

I believe that sender on fuel tank registers 0 when the arm is all the way down, or empty, and 90 when it is full. If there is any resistance anywhere between the fuel sender and the gas gauge it would throw off the reading.

You can disconnect the connection to the gas tank and test there to see if the resistance in on the connection to fuel gauge. If it over 90 you know something is wrong.

Most likely you have a bad fuel sender. You can get one from Advanced for around $60. Take your old sender with you to make sure you get the right one. S10s came with either 20 0r 13 gallon tank and the fuel sender is bigger if you have a 20 gallon tanks. You can take a multimeter to the store to test the sender it should be 0 all the way down and 90 all the way up.