Alright for about the last 6 months my gas gauge (97 civic LX w/ B20B4) for some reason will go all the way up past full line and stay there even if there is no gas in the car. and SOMETIMES when i shut the car off and leave the key on accessory it will go back to the real reading of gas. im just wondering if the sending unit is bad. i havent taken the back seat out to pull the sending unit or anything but is there anything i should be looking for? and its not the swap that is causing it because it did it even before i swapped the motor. also it is the stock cluster that came with the car.

 

it sounds like you likely have a bad connection somewhere, based off the fact that you said sometimes you can get it to read correctly. I bet there is a wire that is touching it giving it too much power. From what i know the sending unit is basically just a resistor that decreases in resistance as it moves lower. So if a wire is touching the wire that should be going to you gauge and is giving it power it could cause it to read full all the time. I am nt sure on this but what i am saying is check your wiring first because that sounds like your problem.

 

Ill have to go over the wiring tomorrow....if its not that then what else? lol

 

as joelmatt said.. a full gas tank reading indicates a 12v+ reading. find out how it is getting this 12 volts