Inaccurate Gas Gauge?

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I think I have two separate problems. First, when I drove all the way to empty and then past it, the light never came on. I think the bulb might be out. However when I filled up when it was at E, I only got 18 gallons out of the 25 gallon tank. Is this normal behavior? Should I be able to go like 50 miles on empty?
 
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I'll also add that even thought I've only been doing city driving, my average city MPG is about 8.3. EPA says 12. I drive very mindfully. What am I doing wrong? Just had a full tune up too, is totally stock
 

inkpot

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Tire size and gearing will affect how you calculate MPG. 80 series fuel gauges seem to be on E and trip the red light with AROUND 5 gallons remaining.
YRMV.
 

Corbet

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Mine has to be solidly on “E” for the light to come on. At that point I have 5 gallons remaining based on over a decade of such fill ups.

I would say the OP’s truck is acting normal except the 8 MPG part.
 
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red light indicates when 5 gallons remain. you're correct that the tank holds 25 gallons total.
Thanks everyone for the help. I'll test it out myself with more confidence. I was concerned that the bulb might be out, then remembered I had just replaced all the bulbs back there.
 
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Your mileage may actually be 8.5..... If all your trips are short (3 miles or less each time) then the engine never warms up enough to go the "closed loop" condition that changes your air to fuel ratios and improve the gas mileage.

Think of the old cars, it's like driving with the choke on all the time, starving it for air to keep the higher amount of fuel in it and burning lots of it.
 

surfpig

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I have thought my "E" light was out too from time to time. But it does come on eventually. After it comes on and stays on, it takes about 21 gallons to fill it up. If you really want to test it, run it empty and see what it takes to fill it up. Don't forget to bring extra gas!

:lol:
 

Kernal

 
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I've done that, run it empty, not entirely on purpose, but was pushing
the envelope to see how far I could drive after the orange light came on,
and it was pretty much where 5 gallons would take me, highway driving.

Around town I figure I safely have ~3 gallons worth of miles, on the highway ~4 gallons (max) worth of miles remaining once the light comes on. After doing that a few times, on the average I've found between 1 and 1-1/2 gallons remaining in the tank, based on what it takes to fill up the tank.

I don't recommend pushing it however, I was lucky, twice,
when I ran out of gas; once I missed an off ramp but could walk to the next station after the engine died a few miles down the highway, another time I had enough momentum to coast down hill and right up to the pump.
 

ppc

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I would forgo the experiment of running the tank to empty. The fuel pump gets cooled by both the "cool" fuel running through and surrounding the pump. Heat buildup can reduce the life of the pump.
 
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I thought my bulb was out but got brave enough to drive it til the light comes on. For mine the gage is well below the E line before it starts to come on. Everyone is right once it comes on you have 4-5 gal.
 
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I would forgo the experiment of running the tank to empty. The fuel pump gets cooled by both the "cool" fuel running through and surrounding the pump. Heat buildup can reduce the life of the pump.
Yeah these pumps die all the time :meh:
 
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On my original gas tank, my low fuel light came on at EXACTLY 5 gallons left. That tank held exactly 25 gallons.

After it cracked and I replaced it (and used the same fuel pump and sending unit) now, when the light comes on, I only have 3 gallons remaining. The new tank holds 25 gallons. If I assume that I'm getting 12 MPG (which is about average), then I have 36 miles before empty when the light comes on and there's not a lot of fluff in that.
 
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