Fuel Reserve Setting in 2002 Tahoe Z71

[sgiangregorio]

Ok Guys, here's a question that neither the dealership nor the Chevy 800 Customer Service line could answer:

 

In a 2002 Tahoe Z71 (26 gallon tank), what is the computer set to in terms of when the Low Fuel light comes on?

 

Here's why I ask. I had a 2001 Silverado 2500HD with the 8.1L engine. If I got gas within a few miles of the low fuel light coming on, the truck would take about 24 gallons, meaning about a two gallon reserve.

 

With the Tahoe, if I get gas right away, it takes about 21.5-22 gallons. I guess GM could program the computer different figuring the Tahoe is more of a family vehicle and that they'd let you know sooner.

 

My concern is that maybe the truck can't register the last few gallons, so when it comes on at say 22 gallons, I can really only use 24 of them (which would be the same ratio as the Silverado), but that wouldn't make sense since the tank is level as normal.

 

Anyone know for sure? I'm just trying to figure out how much "wiggle room" I have when the light comes on.

 

Thanks!

[RyanbabZ71]

my truck usually lights up the low fuel when there is between 4 and 5 gallons in the tank.  I think the actual value is when there is only 20% gasoline left in the tank which would be 5.2 gallons left

[nonstop]

I don't think the computer monitors fuel level directly.

 

On the sending unit you have a float attached to an electical wiper that moves up and down, as the fuel level changes the wiper will ride up and down. Sending info to the gauge, and computer.

 

When it reaches a set point in its downward postion, it sends a signal to the computer telling it to light the low fuel indicator.

Next time your light comes on , try backing up a hill and it'll go out.

 

I can't imagine that they would all be percicely the same, maybe, but i dought it.

 

[RyanbabZ71]

its not accurate.  I backed in my driveway (uphill slope) and the low fuel light came on.  I pulled out of my driveway and it went off and didnt come back on.

[sgiangregorio]

I completely understand how it measures the level, and that all makes sense (if you're on a hill it could go out) since the fuel is shifting positions. So I would say it is fairly accurate when in consistent circumstances. Just like a glass of water. When it's 3/4 full, and straight up, nothing leaks out. Tip it to 45 degrees and water pours out. I wouldn't say the glass didn't work, just that you have to understand how it works (or for the fuel gauge, what it reads and when it reads it). Plus, don't these gauges work off resistance sent to the gauge from the tank sending unit?

 

But assuming all things being equal (like always on level ground), it consistently comes comes on with 4-5 gallons left. My question is verifying that the fuel pump can get to that remaining 4-5 gallons of fuel. It's not that I would intentionally want to run that low, but in an emergency or something, I just want to know the scoop. If it comes on with 20% remaining, and we can confirm that setting, that's what I'm after. The discrepancy between when it came on in the Silverado and when it comes on in the Tahoe is what got me guessing. The only sure fire way to know if to run it dry, but that's not a fun time, for me or the truck's engine.

 

Thanks

???

[RyanbabZ71]

I ran mine the 2nd wk i had it to almost empty.

 

Coming home from indianapolis.

 

I put in 25.3 gallons  

[sgiangregorio]

25.3 gallons huh? That sounds like what I expected. I wish it could be confirmed though, as to the setting...anyone?

[Redapple]

My light consistantly comes on with about 2 to 3 gallons. I have however put as much as 26.5 gals into it (all the way up to the filler).

 

Bill

[Shaners]

Last fill-up I put 24 gallons in it and no light was on...  However I force fed the last gallon in it, so maybe that was why no light yet...

[sgiangregorio]

Shaners, my experience with my 2500HD was that the light came on with about 2 gallons left, so you're situation is consistent with what mine was. The Tahoe seems different though.

[Bob G.]

I have put 25 gallons in my truck (squeezed in as much as possible) and the Low Fuel Level light was not on. This concerns me since I only get 12mpg during certain driving conditions. I usually fill up at 1/4 tank and don't chance it. My last truck (Dodge Ram 1500) had a 35 gallon tank and could get 27 gallons in it when the light came on consistently.

 

Bob G.

[fdb2010]

Wow, this is scary because my '02 '71 gets about the same amount of fuel.  I was wondering what's the cause, now I know.  Thanks for sharing the information.