Cadillac Seville / Cadillac Eldorado Forum Discussion, 1997 Eldorado gas gauge problems in Past Cadillac Vehicle Discussion; The gas gauge on our 97' Eldorado is not working properly. The gauge reads full most of the time so ...
The gas gauge on our 97' Eldorado is not working properly. The gauge reads full most of the time so we never know whats in the tank, so we have to keep track using the trip gauge and do the math. The digital display seams to be in line with the gauge because the trip meter jumps around following the gauge. I read something that said to clean the contacts on the top of the gas tank. Not sure if I have to pull the tank or if this is even the right fix for the problem. This is the first Cadillac that we have had as it was inherited. The car is in great shape and I would like to keep it that way , I have worked on all my vehicles through the years and want to make sure I am doing the right thing.
You can try to clean the contacts you can try (it will be recommended) to pour some solution X in the fuel tank.
But most likely the issue is the fuel sender unit. You have a wire coiled on a semicircular support. Over the coils there is a contact (at the end of an arm connected to a float) sliding back and forth. The whole assembly is basically a variable resistor.
In time the contact go bad (loose, broken or dirty).
You most likely need to replace the fuel sender unit. You can find just the sender unit or the full fuel pump/sender unit.
Since in your vehicle is a tank drop job (not easy) I wold recommend to replace the whole assembly, if the sender unit fails what you expect the fuel pump will do next.
Also is recommended to avoid driving on near empty tank, the gas actually acts as coolant for the fuel pump (it makes no difference on the wallet of the tank if full or empy, after all you still have to pay for the fuel you use).
For the reasons behind several members recommending "Solution X" (Chevron TECHRON), Google it. TECHRON is a powerful fuel system cleaner (it's a component of Top Tier gasolines - Google it) and one of its claimed "cleanings" is to attack sulfur deposits on the fuel level sender resistance bar. If it solves your level sender problem, well and good; otherwise you'll have spent about $12.99 for clean fuel injector tips.