1997 Cadillac Eldorado fuel gauge not reading fuel level correctly

Putting gas has nothing to do with you fuel gauge problem
Must problems to add fuel and comes out can be cause by air flow in the tank, also it is recommended to fuel with the engine turn off so the pressure from fuel pump going back to the tank will not affect the fueling , about you fuel gauge not working properly can be cause by a electrical problem such wiring or defective gauge or can be fuel sender problem with most the time it is install on fuel pump assy.

Its part off the fuel pump in the gas tank

I have answered this already at the duplicate post.

what could be the problem ???? The problem is you tried to fix something you have no clue how it works .... Your best bet , take it to a qualified repair shop. You have no idea of the complexity of these cadillac systems . I know you don't have a $ 5000 dollar factory scan tool or equivalent to diagnose . The sending unit in the fuel tank is a input to the BCM . The BCM sends this info to the instrument cluster over the class 2 serial data network - communication network for the control modules on the vehicle. Fuel Level
The body control module (PZM) monitors the fuel level sender input in order to determine the current fuel level. The PZM filters the input and sends a message via the Class 2 serial data line. The IPC receives this message and displays the current fuel level. The fuel level is sent from the PZM to the IPC at changes of 0.5 L (0.02 gal) or on the request of the IPC, with a resolution of 0.04 L (0.01 gal).
• For the digital IPC, when the fuel level is above 18.5 gal, the IPC displays an F. For readings between 18.5-2.5 gal, whole gallon/liter numbers are displayed. When the fuel level reaches 3.0 gal the message FUEL LEVEL LOW is displayed on the driver message center. When the fuel level reaches 2.5 gal, the IPC displays an E. When the fuel level is 1.2 gal or below the IPC displays a flashing E.
• For the analog IPC, when the fuel level is above 18.5 gal, the fuel gauge pointer is on F. When the fuel level is below 2.5 gal the fuel gauge pointer moves to E. When the fuel level is below 3.0 gal the IPC displays a FUEL LEVEL LOW message.
If the updates are not received or a communication error is detected, the IPC performs the following actions:
• For the digital IPC, the fuel gauge is dashed.
• For the analog IPC, the fuel gauge pointer moves to E.

Fuel Gage Inaccurate or Inoperative
Circuit Description
The IPC monitors the fuel level sent by the PZM through the class 2 serial data line. The IPC software controls one of the following two gauge types:
• A digital gauge consisting if a two-digit numeric seven-segment display
• An analog gauge consisting of a needle pointer.
The IPC interpolates and scales the fuel level information that the IPC receives from the PZM.
When you operate the vehicle in diagnostic mode, either in the vehicle diagnostic system or with a scan tool connected, the fuel signal supplied to the IPC is not filtered by the PZM. The unfiltered fuel signal causes the IPC to show real time readings and may be mistaken as an erratic fuel level display.
Diagnostic Aids
Connect a scan tool to the DLC.
Test for any set DTCs if no DTCs are set current. Refer to System Check in Body Control Module (PZM) Diagnosis.

Your best bet , take your vehicle to a qualified repair shop.

Gm cars are well known for this problem.You will need to have the ignition switch and ignition lock cylinder replaced the computer is not able to read the code from the ignition key.If you have a spare key thats not worn to bad it might work.

The fuel pump sending unit is most likely defective or out of calibration. It could of got bent or damaged when the pump was replaced & may need to be adjusted. Hope this helps.

Hello: This could be the fuel level sensor is not connected or the sensor assembly was damaged or bent when assembly was reinstalled or the fuel pump was not installed on the sending unit correctly.

There isa button on your Info display center next to the fuel reset button that changes from lires to gallons.

Change fuel filter, may have pulled some debris from tank into fuel filter stopping it up

Not a fuse.There is no fuse for the level sensor.These are known for fuel level sensors being bad.Sometimes they will leave a code and sometimes not.You can check codes and see if you have a fuel level sensor code.The other thing you can do is check the connections and make sure they are clean and on securely.If you find that the level sensor is bad.Then it is easier to replace if the fuel in the tank is as low as possible for easier removal of the fuel tank.Hope this helps.Good luck.