Fuel Gauge And Tank Capacity

[Jdavenport0622]

I have a 2005 Tahoe. A quick google search says it has a 26 gallon tank. Haven’t paid much attention to it before but noticed today that my gauge is right at empty and the truck says I’ve used 18 gallons. Is it actually a 26 gallon tank and my gauge is just off or could it be a smaller tank?

 

[OR VietVet]

Gauge is likely off a little bit but I would be concerned about running it to empty, in case your info of 18 gallons is incorrect. I know others will say the fuel pump design on the 05, like mine, is such that running on empty does not damage the pump but I disagree and think of 1/4 tank as empty. Your truck and your call.

 

[Jdavenport0622]

Would the fuel pump have to be replaced to fix the gauge issue or is there something else that needs to be done?

 

[OR VietVet]

That is why I said, likely the gauge. You have a sending unit attached to the pump that sends a signal to the gauge at the dash. This is where vehicle/engine info would be so nice to have. I am assuming you have the 5.3 engine. but have no idea whether you have gas or flex fuel engine. 8th digit of VIN is a "T", gas engine or is a "Z" for flex fuel engine?

I can look up the fuel pump for it and show you a pic of it. MAYBE ran close to empty enough times that you have done damage to sender on pump. Maybe not. I do not know. The only time my 05 has ever been that low and a low fuel light came on, was when I recently ran tank real low because of my plans of replacing the fuel pump.

 

[swathdiver]

I have a 2005 Tahoe. A quick google search says it has a 26 gallon tank. Haven’t paid much attention to it before but noticed today that my gauge is right at empty and the truck says I’ve used 18 gallons. Is it actually a 26 gallon tank and my gauge is just off or could it be a smaller tank?

26 gallons. Could some jerk have siphoned off some fuel? How about a leaky line over the tank that's not easy to notice? When I was a kid, my first car got 6 miles to the gallon, then 5, then 4 and on down to 1.1 before I finally found all of the leaks! LOL

You can replace the sending unit separately from the pump, am looking at the parts on Rock Auto. SK1265 and SK1157 for FlexFuel.

 

[Fless]

Would the fuel pump have to be replaced to fix the gauge issue or is there something else that needs to be done?

It's a 26-gallon tank unless it's been changed out for some frankenstein tank. The fuel level issue could be either one of those, or a combination of both.

What I did is run the tank down until the low fuel light comes on (be sure yours works first; it should light up for a few seconds on startup), then note the gauge position. Fill up without topping off after the pump handle resets. You never want to overfill these things, that can cause the evap system to need repair. Anyway, note how much fuel it took when the light came on, and you'll then know how much is in reserve. I think mine has 4 or 5 gallons left when I do that; plenty for me to find more fuel but not panic.

 

[swathdiver]

It's a 26-gallon tank unless it's been changed out for some frankenstein tank. The fuel level issue could be either one of those, or a combination of both.

What I did is run the tank down until the low fuel light comes on (be sure yours works first; it should light up for a few seconds on startup), then note the gauge position. Fill up without topping off after the pump handle resets. You never want to overfill these things, that can cause the evap system to need repair. Anyway, note how much fuel it took when the light came on, and you'll then know how much is in reserve. I think mine has 4 or 5 gallons left when I do that; plenty for me to find more fuel but not panic.

 

[S33k3r]

View attachment 346601

I shamelessly stole the above image and shared it in a Quadrasteer grou pin which I am a member... Someone els fired back with this -- figured I'd share with y'all.

 

[iamdub]

I have a 2005 Tahoe. A quick google search says it has a 26 gallon tank. Haven’t paid much attention to it before but noticed today that my gauge is right at empty and the truck says I’ve used 18 gallons. Is it actually a 26 gallon tank and my gauge is just off or could it be a smaller tank?

The sensor on the pump module could be faulty. I found out AFTER I replaced my pump module that the level sensor was bad. I had a 1/4 tank when I pulled it in the shop to replace the pump module and maybe 1/16th when I started it up afterwards. I didn't drain any.

I tested it with my DVOM. It would read normally from full to around the 1/4 tank area, then go to open circuit anywhere beyond that.

If someone could get you a wiring diagram, you could test the circuit coming from the level sensor in the tank. If you've used 18 gallons, then you should have about 8 gallons left. This should put the sensor reading around 1/3 tank, which, according to the charts posted above, is the high end of "E" and the low end of 1/4, so in the 70s for the impedance (resistance/ohms). If that's what your meter reads but the gauge says otherwise, then your gauge has a faulty stepper motor. My bet is the level sensor is bad.

 

[Teamiez]

those charts seem pretty spot on, I noticed with my original pump that the gauge would hangout for a while in some spots then drop quick, with the new pump it actually goes down accordingly & accurately.