Fuel gauge issue

[Chughart]

Hey guys I have a slight problem, I was driving on my way home from work and the low fuel light came on and the gauge is pegged to empty it had about 3/4 of a tank before the gauge died. Is there any common issue with this other then the pump assembly? It runs fine just the gauge is dead. Also if I turn it off and back on the gauge doesn’t even move. Any suggestions would be greatly appreciated!

Thanks, chris

 

[Fless]

Consider putting your year/make/model in your signature so we know what you're driving. Otherwise put it in each of your posts.

Nonfunctioning or malfunctioning gauges in these model years is generally due to bad gauge stepper motors. Each gauge has one. If the low fuel light extinguishes when you add gas then it's likely the gauge's stepper motor is bad. Numerous places do gauge repair and, if you're somewhat handy, it can be a DIY project.

 

[Chughart]

Oops my bad lol it’s an 02 Tahoe lt flex fuel. I plan on checking it tomorrow But didn’t know if it more likely be the pump unit or the gauge

 

[Fless]

As another test you could use a scan tool to view the reported fuel level; that's independent of what the gauge shows. But if you're able to add 20 gallons or so into the tank after the low fuel light comes on, then the gauge or its cluster circuit is likely faulty. The low fuel light is not driven by the gauge.

 

[Chughart]

it has about 3/4 of a tank of gas in it. i got in it this morning and the gauge now works? so if it happens again then i will check it with a scan tool and see what it says. im just hoping it isnt the sending unit in the tank cause the stepper motor in the gauge is cheaper and easier then the in tank pump lol. but i will keep you guys posted on what happens.

 

[afpj]

Consider putting some Techron fuel system cleaner through there for a couple of tanks, starting with your 3/4 tank now…maybe there’s some varnish or other gunk thats making the float “sticky”, although one would think it sticks in the fuller position. Total WAG… At any rate, it couldn’t hurt.

 

[treehan77]

Mine would do all kinds of weird stuff intermittently. Say 1/4 when 3/4 full of parked one way, the opposite parked the other way. Even Pegged empty when full driving down the highway etc. only when I put in a new fuel pump, it was fixed

 

[rockola1971]

Mine would do all kinds of weird stuff intermittently. Say 1/4 when 3/4 full of parked one way, the opposite parked the other way. Even Pegged empty when full driving down the highway etc. only when I put in a new fuel pump, it was fixed

The fuel pump itself has nothing to do with the fuel gauge operation. Its the fuel level sensor which the float is connected to that provides the signal to the fuel gauge. You do get a new fuel level sensor when you buy a complete new fuel pump module assembly.

I would check with a scanner to see what the fuel level sensor is reporting and compare to what the gauge is showing. Whichever one is incorrect is the problem child. The fuel gauge "at fault" could be a bad steppr motor which drives the needle for the fuel gauge or there could be silver migration bridging traces on the circuit board of the instrument cluster or a simple busted solder joint on the board of the instrument cluster.

 

[treehan77]

Yeah, that’s why it started working… I don’t think anybody is just gonna change out the level sensor only.

 

[afpj]

For the 2002 Tahoe 5.3 FF 4x4, The low fuel light activates via the sending unit, and is independent of the cluster gauge correct? if the sender unit is functioning properly with gas in the tank, but the gauge (stepper motor) is dead, you can have the gauge read empty but the fuel light will not light up with sufficient gas in the tank?

my mechanic said voltage from sender is good…thinks gauge is on its way out, but I question where the low fuel light trigger is from. appreciate any clarification.