[evintho]

Originally Posted by 88build

I just read your reply but have not gone out and looked. Where for the ground? Is it a seperate wire connected to the sender or can I just ground the tank. I'm going to go look now. What do you mean behind the connector?

Climb under the back of the car. About in the middle of the tank, tucked up between the tank and bumper should be a fairly long, round 4-prong connector. Disconnect it. The YEL/WHT wire is actually the sending unit wire. The black wire is the ground wire. I don't remember what the other 2 wires are for but it's not important now. Attach a small aligator clip to the end of a 16 ga wire. Clip the aligator clip to the prong, inside the connector that's attached to the black wire. Run the other end of your wire to a good ground. If the needle still goes to full with an empty tank you've eliminated one of the culprits. Your factory ground wire is good. As stated, it's probably a different resistance in your sending unit.

Originally Posted by 88build

I found online that a 88 fuel sender is 16-158 ohms. Doesn't seem that far off, or is it?

My 33/140 is straight out of the factory shop manual for my '89. Maybe there's a slight difference between '88-'89. Doesn't make any difference though. I just had my Autometer Phantom fuel gauge recalibrated for my Mustang by Autometer. Their gauge read the high number as empty and the low number as full. They reversed the resistance reading and recalibrated it for 16-158 ohms. It's a slightly wider range so maybe the needle will bottom out when there's still a bit of fuel left in the tank and it may top out when it's not completely full. Either way, it should work.