Fuel gauge sporadic

Wild Bill's ‘98 TJ

Wild Bill's ‘98 TJ

Member
Joined
Oct 8, 2022
Messages
48
Location
Laurel, Ms
1998 TJ 4.0 Automatic
When my gauge gets between 1/2 and 1/4, it jumps to the red and the light comes on. After driving it a couple more times it will jump back up to around 1/4 and seems to be accurate at that point until truly empty.
I can set my trip meter but it drives me insane. Any suggestions appreciated!
Thanks
 
Almost definitely a problem with the fuel level float mechanism inside the fuel tank.
You will need to drop the fuel tank to access the fuel level mechanism to inspect the float, float arm and sensor potentiometer.
Due to the amount of work involved in dropping the fuel tank; I would suggest you purchase a OEM fuel pump assembly (if you can find one) and replaced the fuel pump/fuel level sensor mechanism.
There are numerous videos available on YouTube outlining the steps involved in lowering the fuel tank.
 
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At the risk of suggesting a “mechanic in a can “ fix, GM once issued a TSB suggesting the use of Techron fuel cleaner to clean the build up of sulfur deposits from the sending units. I only mention this because in my first hand experience it did successfully fix a sticking/erratic fuel gauge in my suburban. Subsequently it also fixed the unit in my Polaris Atv. As said replacing the sending unit is the guaranteed fix but for $10 and some down time, it’s worth a try.
 
CharlesHS said:
Almost definitely a problem with the fuel level float mechanism inside the fuel tank.
You will need to drop the fuel tank to access the fuel level mechanism to inspect the float, float arm and sensor potentiometer.
Due to the amount of work involved in dropping the fuel tank; I would suggest you purchase a OEM fuel pump assembly (if you can find one) and replaced the fuel pump/fuel level sensor mechanism.
There are numerous videos available on YouTube outlining the steps involved in lowering the fuel tank.
Click to expand...

10-4! That was my fear. 😂
I may set my OCD aside and just live with it. Thanks for the reply.
 
Juggernaut said:
At the risk of suggesting a “mechanic in a can “ fix, GM once issued a TSB suggesting the use of Techron fuel cleaner to clean the build up of sulfur deposits from the sending units. I only mention this because in my first hand experience it did successfully fix a sticking/erratic fuel gauge in my suburban. Subsequently it also fixed the unit in my Polaris Atv. As said replacing the sending unit is the guaranteed fix but for $10 and some down time, it’s worth a try.
Click to expand...

I’ve been curious if an additive might work. For the price of lunch, I may give it a whirl.
Thanks for the reply and suggestion.
 
Juggernaut said:
At the risk of suggesting a “mechanic in a can “ fix, GM once issued a TSB suggesting the use of Techron fuel cleaner to clean the build up of sulfur deposits from the sending units. I only mention this because in my first hand experience it did successfully fix a sticking/erratic fuel gauge in my suburban. Subsequently it also fixed the unit in my Polaris Atv. As said replacing the sending unit is the guaranteed fix but for $10 and some down time, it’s worth a try.
Click to expand...

this is a fix on the c5 vettes, had one and it worked wonders, I have a intermittent issue where mine just doesn't read that it has gas and if I turn the jeep off and back on its back to normal.
 
I have the same issue, I just reset the trip meter at fill up and refill at 175 miles on the trip meter.
 
Wild Bill's ‘98 TJ said:
1998 TJ 4.0 Automatic
When my gauge gets between 1/2 and 1/4, it jumps to the red and the light comes on. After driving it a couple more times it will jump back up to around 1/4 and seems to be accurate at that point until truly empty.
I can set my trip meter but it drives me insane. Any suggestions appreciated!
Thanks
Click to expand...

If it’s good between 1/2 and full, then yeah like Charles said definitely something wrong with the sending unit. If you replace the pump, get the carriage bolts and retainers and corresponding nuts for the fuel tank skid. Better to prepare for the worst than hope for the best.
 
I probably should just check the wiring diagram, but does the fuel sender share the same power/ground as the fuel pump? If not, it could be a bad connection. My money is on the sender, but I just wanted to consider other possible causes.
 
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