Re: 1994 Chrysler LHS, fuel gauge question
The fuel pump and sending unit are probably a singe assembly. It is a pain to drop the tank, but as long as it is near empty, it isn't that bad. What you can do is pull the carpeting in the trunk and see if there is an access panel in the floor above the tank. Every once in a awhile a car manufacturer does this to make fuel pump/sending unit replacement easier (but I wouldn't count on it). The sending unit is really a variable potentiometer. It is a curved winding of wires. The float is connected to a long arm, and pivots. On the other side of the pivot is a contact that is always in contact with the curved wire winding. As the level drops, the contact is moved along this winding. The electrical resistance changes as the contact is moved along the winding. Sometimes the winding gets a damaged section on it, or a bit of junk gets lodged on it, and when the fuel level gets to the point that the contact touches the bad area, you lose gauge accuracy. <br /><br />I actually have the same problem on my better halfs Jeep Grand Cherokee. I replaced the fuel pump for a different reason, and now it does the same thing, erratic guage behavior when 3/4 or more of a tankful. I still have my old pump and sending unit assembly, when I get bored in the summer I'll drop the tank, pull the assembly, and swap the old sending unit back onto the new pump housing, that will fix my problem.
<br />M.Y.