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fuel gauge not accurate

Posted: Mon Aug 13, 2012 3:30 pm
by snira
Hello,
Everytime that the nidle of the fuel gauge is getting closer to the orange zone it's taking very short time untill it's going under it, it's not going down progressively, it's just fall right down under the orange and stay there, And even if i drive more miles on it, there is more and more to drive.
this is not happening when the tank has fuel above the orange zone.
Because of this problem I can't really know how much fuel really left in the tank and when is it going to run out of fuel.
What part is not functioning right?
thanks

Re: fuel gauge not accurate

Posted: Mon Aug 13, 2012 8:54 pm
by MattStrike
Well, short answer is next time it touches the orange zone is to top off the tank. Then subtract the tank capacity from the owners manual (18 gallons) from what you put in. Then you know how much is left when you first reach the orange zone. Every car is slightly different.

Re: fuel gauge not accurate

Posted: Mon Aug 13, 2012 9:33 pm
by Bob Dillon
It's not the gauge, it's the shape of the tank. It's L-shaped with the bottom leg of the "L" facing towards the front of the car. This makes the gauge wackier than a traditionally-shaped tank.

Re: fuel gauge not accurate

Posted: Tue Aug 14, 2012 5:21 am
by snira
thanks,
so you guys think that the reason is just because the shape of the tank, and that when the fuel is going down in the tank the gauge will be less accurate, so from my understanding replacing the fuel level sensor will not change anything, right?

Re: fuel gauge not accurate

Posted: Wed Aug 15, 2012 8:22 pm
by Bugsi
Believe it or not, there's a factory service bulletin to reprogram the PCM to give a more consistently progressing decrease reading for the fuel level. If you find yourself at a GM dealer, have them look it up and patch your PCM. I don't have the bulletin number, but I know there is one. Whether it actually fixes your problem is another thing, but worth trying.

Re: fuel gauge not accurate

Posted: Wed Aug 15, 2012 10:12 pm
by 1oldman
I've been around "tired iron" all my life. In-accurate fuel gauges are typical of all the all cars/trucks I've ever been around. - BC

Re: fuel gauge not accurate

Posted: Sat Aug 18, 2012 1:07 pm
by Bob Dillon
1oldman wrote:I've been around "tired iron" all my life. In-accurate fuel gauges are typical of all the all cars/trucks I've ever been around. - BC
Yup. My tagline toy has an inaccurate gauge, I just put $20 in every time I drive it around the block. ;)

Re: fuel gauge not accurate

Posted: Sat Aug 18, 2012 1:28 pm
by reb
TSB:

FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY

Date Reported DECEMBER 01 1997
NHTSA Reference #600209
TSB Reference #738325

Description: CUSTOMERS MAY COMPLAIN THAT THE FUEL GAUGE REMAINS ON "FULL" TOO LONG. *TT

Repair Information for NHTSA #600209

Re: fuel gauge not accurate

Posted: Mon Aug 20, 2012 10:13 pm
by renchjeep
Just a word (or several!) of advice--the electric fuel pump inside your fuel tank is cooled by the surrounding fuel. Running below 1/4 tank consistantly can cause the pump to overheat, and cause fuel pump failure. Plus, by running the tank lower than 1/4, you stand the chance of sucking dirt and debris from the bottom of the fuel tank, which can prematurely clog the fuel filter. This can also lead to fuel pump failure due to overworking the pump.

Fill 'er up at 1/4 tank. It doesn't cost as much per fill-up, and just may save your fuel pump. Also, change the fuel filter every 20k. Cheap insurance...

Re: fuel gauge not accurate

Posted: Tue Aug 21, 2012 12:42 am
by 1oldman
renchjeep wrote:Just a word (or several!) of advice--the electric fuel pump inside your fuel tank is cooled by the surrounding fuel. Running below 1/4 tank consistantly can cause the pump to overheat, and cause fuel pump failure. Plus, by running the tank lower than 1/4, you stand the chance of sucking dirt and debris from the bottom of the fuel tank, which can prematurely clog the fuel filter. This can also lead to fuel pump failure due to overworking the pump.

Fill 'er up at 1/4 tank. It doesn't cost as much per fill-up, and just may save your fuel pump. Also, change the fuel filter every 20k. Cheap insurance...

X2

I mark on my filter with a sharpie the date and mileage installed in case I forget (ha ha ha - I always forget!) - BC

Re: fuel gauge not accurate

Posted: Thu Aug 23, 2012 2:36 am
by renchjeep
1oldman--I do exactly the same on all of my vehicles, and the Police fleet that I take care of. It never hurts to have a reminder...and as I get older, I seem to need more reminders for the "simple" stuff!

Now if I could just remember where I put my keys.....and my glasses.....

Seriously, marking your fuel filter with mileage/date will help you, and any other future "mechanics" or owners, to get a grip on possible maintenance (or lack thereof) issues.