Does anybody know the answer to this question???????
YES I HAVE THE ANSWER...REPLACE THE TEMP GUAGE. ITS NOT AS HARD AS YOU WOULD THINK...ABOUT A 20 MIN. JOB ------------------------------------------------
I tried replacing the temp gauge but that wasn't the problem for me. On top of the engine is a temp sender that is all so easy to get to but it is for the engine computer. The temp sender for the gauge is under the water pump. My temp sender went bad because the water pump started leaking. It is like the engine is headed for a major problem of over heating but it disables the temp sender which warns the driver of over heating.
It is not easy to change the temp sender but it is doable if you pull off the thermostat housing. Don't put the old thermostat back in. Also, don't get an aftermarket temp sender, I got one and it reads 3/4 hot all the time. It only cost me $5 but I wish I had have bought from the dealer what ever it cost.
The fuel pump may be fine but the sending unit may not be. The sending unit is probably the most common cause of fuel gauge failure.
The sending unit you have may be the type used for an "idiot light" only and your system has a gauge. Try replacing the sending unit with a gauge type.
There is a sending unit laocated at the fuel pump that sends info to the gas gauge. This can malfunction with no reason at all. I am betting that this is the reason since your gauge still moves. If the gauge is bad usually it wont move at all and is not a common thing now a days anyway. The sending unit is more common. Hope this helps.
Be sure you are replacing the temp sending unit for a gauge application. The parts counter person may have given you one for an idiot light.
More than likely the fuel gauge sending unit located in the fuel tank is faulty.
PERHAPS THE PROBLEM LIES SOMEPLACE ELSE. IT MAY BE THE GAUGE ITSELF OR A WIRING PROBLEM.
if you've replaced those 2 parts you should check the fuses and or relays. If those are good then find the ground from the pump and or sending unit and trace it back. also make sure that the sending unit is getting power. that should do it.
The outside air temperature should still have the same reading. The installed sending unit should not affect the temperature gauge.
The sending unit(float) has failed. The sending unit is attached to the fuel pump module in the fuel tank.
Maybe bad sending unitBad/Damaged fuel sending unit. Bad/damaged wiring. Locate the wires of the fuel sending unit at the fuel tank and unplug them, see if that makes the fuel gauge to be stable (may be up all the way of down all the way, but must stop moving).If the gauge still acts erratic chances are your wiring is wring of finally (but not common) the guague itself on the dash it's damaged..
It does NOT automatically mean you have 80# of pressure! NEVER trust your gauges as being the 'last word'. They're notoriously cranky on some older XJ's. (Usually due to gauge cluster connection issues or harness oxidation.) Chances are that you have a defective oil pressure sending unit. Rarely the gauge goes bad. Remove the wire on the sending unit and see if that changes the reading. If it does, replace the sending unit. If not, I'd still replace the sending unit. After you confirm the oil pressure sending unit is good, check the oil pressure relief valve. It may be stuck closed resulting in high pressure reading.
It does NOT automatically mean you have 80# of pressure! NEVER trust your gauges as being the 'last word'. They're notoriously cranky on some older XJ's. (Usually due to gauge cluster connection issues or harness oxidation.) Chances are that you have a defective oil pressure sending unit. Rarely the gauge goes bad. Remove the wire on the sending unit and see if that changes the reading. If it does, replace the sending unit. If not, I'd still replace the sending unit. After you confirm the oil pressure sending unit is good, check the oil pressure relief valve. It may be stuck closed resulting in high pressure reading.