Howdy, I traded my 95 Blazer in on a 98 Jimmy, a couple of weeks ago. Anyway, the manual says it has an 18 gallon tank. Well, I've never gotten more than 12.5 gallons in it. It will be all the way down on E, and the "low fuel" light flashing at me(so I'm afraid to try and go much farther), and I can't get more than 12.5 gallons into it(and it then reads full). WTF?
I figure the gauge is just off, but the low fuel light flashing too, has me stumped. Any ideas?
THANKS!

 

sounds like your float is stuck. Next time after you fillup, crawl under and knock on the fuel tank. remember that sound. then when the fuel tank is "supposedly almost empty" do the same. My guess is that the float is stuck and you are only using about 2/3s of your tank

 

GM fuel sending units are notoriously inaccurate. If you have seen them on E-bay you would see why. They work like an old toilet tank float, hinged at a fixed point with electric contacs to determine fuel level. If you notice that when you park/drive up/down and incline the fuel gauge changes...so depending where the float sits in the tank determines your gauges readout of fuel level... And if you call GM they will tell you that the gauge is not designed to be an accurate source to determine fuel level, it is only provided as a courtesy "feature".

Plus the only way to get accurate fuel levels would be to input your fuel purchase and then allow the computer to determine the mpg and then guestimate the driving range for the fuel in the tank...remembering the fuel pump will only pickup about 16gal of an 18gal tank....so if you want an accurate fuel guage don't buy GM even new cars with computers designed to guage fuel use (Pontiac Solstice etc) are still not that accurate...but they are better, they still use the toilet tank float setup but now they are connected to the computer....

 

So the "low fuel" light is run directly by the float? I thought that it might be possible that they were independent of each other. ?

I guess I need to throw a can of gas in the back, and see just how far I can go!!! I'm just always afraid that it'll die while I'm blocking a stoplight or something.

Can running it dry........ help to re-adjust the float, to the proper placement?