View Full Version : Fuel guage problems

07-20-08, 11:37 AM
I have a 2008 STS and have problems with the fuel guage. I have yet to put more than 12 gallons of fuel in the car. I can leave my house with the guage showing a half tank of gas and literally watch the needle move down to almost empty as I drive -- and i'm talking about out 20 minute drive. I've had it into the dealer once and they replaced the sensors in both tanks. Still have the problem. Taking it in again tomorrow for the same issue. Has anyone had this problem? Dealer said the only bulletin he found was one for the tank being "hard to fill". Could that be the same issue?


07-21-08, 06:06 AM
I have a 2008 with about 7,200 miles. A few days ago I noticed I had just under 1/4 a tank; I was expecting it to be about 1/2 but just thought I hadn't been paying attention. Then about 30 minutes later I looked again and it was back near 1/2. The next day (after not much driving) it was about 1/8 so I filled up; it took 13 gallons. I guess I'll keep an eye on it and see if this is a problem.

07-21-08, 06:54 AM
If there is a problem with the fuel transfer system the computer should set a code and the gage will default to empty.
They may have started with a fuel transfer problem and thrown two sensors at it.
It takes more knowledge than how to read a TSB to properly diagnose this system and not many guys are armed for it, mentally.

Knowing that it has 2 new sensors, if it has transfer issues it will probably need a pump. I have seen the jets clog in the transfer system causing the fuel to stay trapped on the left side of the tank. This will cause the gage to go to E.
There are other things too... like... did they reconnect the transfer hose when they reassembled the tank??? ;)

07-21-08, 12:19 PM
This has been an issue with GM for years. Old model STS did it. Denali and a few other GM models did it as well. My 2006 ST-V did it about 5 months ago. It is the sending unit which is part of the pump for the fuel system. It needs to be replaced. Just be glad you don't own the Denali - when the sending unit dies, the vehicle stops dead in its tracks. In the Caddy, it just seems to play havoc with the fuel gauge - one minute you are at 3/4 of a tank, next time you look it reads less than 1/4! I reset the trip odometer at every fill up, so I have a good estimate on how full the tank really is in case it ever happens again. But that should definitely be a warranty item and should be replaced.


07-21-08, 09:14 PM
The worst ones were the 97-03 Corvettes.
The FFS fuel system was less problematic and the new RWD platform cars have this issue rarely, but as I said, the real issue is the guy checking it out.
Does he even know how it works... let alone how to figure out what the specific problem is?

08-11-08, 03:08 PM
Thanks all. They replaced one of the fuel tank sensors again and it is not as bad, but I still funky. Like one of the posters mentioned...sometimes it even "makes fuel". Ha!! If only...

I'll send the sendor info to my service manager and see what he has to say about that idea.