Vibrating Fuel Gauge???

BlackTaz · October 10, 2003

Anyone else encountered a spastic fuel gauge? A while back, on a long road trip, the gauge in my 99 Yukon stuck and showed I still had about 1/8 tank when I ran out of gas... leaving me stranded. It seems to be better around town with a lot of turn-offs/turn-ons. Since then, I haven't really trusted it

Lately, when I turn the key to "on", the fuel gauge slams all the way to the right, well past full, then comes back to the vicinity of the right fuel level. Shortly after that, it started vibrating... really fast, just like one mark to either side, but it's almost a blur.

I suspect it's the sending unit in the fuel tank, rather than the fuel gauge. But, I would feel better about having that replaced if I know that other people have had the same problem and actually solved it by replacing the sending unit (and the fuel pump, I believe).

Thanks for any help!

Tucson_02Silverado · October 11, 2003

Fuel sender!!

When you put the truck in gear, if automatic, the gauge stabilizes but reads wrong.

toddgotfish · October 11, 2003

join the club brother

fill up and drive it til you hit 350 miles

fill up again , repeat

AllGMV8 · October 13, 2003

I'm watching this thread with interest because my fuel gauge needle has the same high-speed vibration but it always reads correctly based on the amount of gas I have to add to fill the truck up. The needle does not stabilize at any time, whether in gear and still, in gear and moving, parked on an incline, etc. It vibrates so fast the needle is a blur, and it's slowly drving me nuts.

After a bout of replacing/upgrading parts on my Caprice to fix a different problem, my wife is not too keen on replacing things to try and fix a problem - she won't let me touch anything unless I can prove it will fix the problem. She caught on to my excuse to upgrade stuff

Adam

BlackTaz · October 14, 2003

Fuel sender!!

When you put the truck in gear, if automatic, the gauge stabilizes but reads wrong.

Actually, the guage doesn't stabilize when I put the trans in gear (yes, it's automagic). It's vibrating most all of the time... driving or stopped; in gear or in park.

Toddgotfish, I've been taking that approach for the past year, but as AllGMV8 put it, it's slowly driving me nuts. Who knows when I'll have to blame it for some bout of road rage!

I'm also hoping, if I end up replacing it, to end up with a fuel gauge that's calibrated a bit better... meaning that when it's full, it reads about "F" and not well-past it... and when it hits "E", I'm d**n near outta gas (rather than having 5 gallons in it still, as it is today). Maybe that's asking too much???

This seems, to me, that it might be a design problem. Related to the sending units that drop to zero, but not the same problem (I've heard that blamed on sulfur in the fuel). If this has happened to as many people as the drop-to-zero problem, then it just might be a problem with the way the sender is built in the first place. If that's the case, then why do I want to put the same one back in there if it will likely have the same problem down the road?

BlackTaz · January 6, 2004

Well, I finally broke down and had the fuel pump and sending unit replaced (one assembly). So, here's an update... unfortunately, it didn't solve the problem with the fuel gauge

So, for others that might have the same problem, I hope this might be helpful. I took it to a shop that checked the signal between the tank and the computer, and then from the computer to the fuel gauge. Both sides of the computer checked out, so they said the most likely culprit was the sending unit in the tank. But, after they replaced the sending unit, the gauge was still vibrating. They said that the computer supplies a modulated pulse width square wave signal to the gauge and that signal looked OK. They now suspect that the gauge is the problem and that it's just not dampening the electrical signal as it should.

The gauge seemed to stick, on long trips, as well as vibrate, so the shop thought the new sending unit might solve the sticking problem, but it didn't. I took a 500 mile trip and watched the gauge along the way... some very strange behavior. When I started on my trip, the gauge showed about 1/2 tank and was vibrating, but then it settled down within about a half-hour and was stable. It didn't move for over 100 miles. After stopping for about 20 minutes, when I turned the key on, the gauge showed 3/16 of a tank (so, it was "stuck" at about 1/2 tank while I was driving). It stayed at 3/16 for the next 40 miles, too.

After I filled up, the needle was right on the "F", but it wasn't vibrating. Over the next 60 miles, it slowly dropped to about 1/2 tank (the tank was still 7/8 full, though). When I turned the engine off, I waited about 5 seconds and turned the key back on and the gauge didn't move. I turned the key to off again, waiting for 10 seconds this time... and the gauge didn't move when I turned it back on. I turned it off for about a minute and when I turned the key back to on, the gauge quickly slammed to the right to about the 5 o'clock position, then came back to settle at 7/8 of a tank (a pretty accurate reading). It's still the same freaky, spastic, fuel gauge.

I don't know if this means the gauge is bad, or not (maybe it's the computer). But, I'm told it will cost about $300-400 to swap out the instrument cluster and I'm not interested in throwing any more money at this problem right now. If anyone else has any experience solving this problem, I'd love to hear!

traxion · January 6, 2004

I dont seem to have the vibrating gauge, but mine when sitting still always goes to empty then the 'low fuel' light comes on until you start going again. It acts pretty funny. The readings are always accurate though.

doverarjim · January 7, 2004

Let me add my troubles to the list: My gas gauge would move back and forth from empty to full never stopping any where, and the idot light never came on so I ran out of gas. Took truck to stealer and they told me it would take an "ECM" at a cost of $365.00 and labor of about $350.00 to pull fuel tank and also replace the in tank fuel filter. It is just easier to watch the mileage and fill up at about 350 miles or so.

BlackTaz · January 7, 2004

Traxion, I've heard the "goes to empty" problem blamed on the type of fuel (some say some brands of fuel have more sulfur than others and it's more than the sender can handle). Some people have had success switching brands of fuel (if you buy one brand all the time). To me, it just means that GM didn't design the fuel sender well enough to handle all the different gasolines. You'd think, after all these years, a fuel sender would be something engineers have down pat. But, I guess sometimes when you try to make things better, you actually can make them worse!

traxion · January 7, 2004

Traxion, I've heard the "goes to empty" problem blamed on the type of fuel (some say some brands of fuel have more sulfur than others and it's more than the sender can handle). Some people have had success switching brands of fuel (if you buy one brand all the time). To me, it just means that GM didn't design the fuel sender well enough to handle all the different gasolines. You'd think, after all these years, a fuel sender would be something engineers have down pat. But, I guess sometimes when you try to make things better, you actually can make them worse!

True that. It doesnt seem to matter what fuel I buy, I get the same thing. I mean its not a big deal just a annoyance. Thanks for the tip. I appretiate it.

MattDewalt · January 7, 2004

Same problem as Traxion. I buy my fuel at different places and the problem still exists. I usually get 350 miles per tank, so if it ever quits, I'll just fill up by milage.