Gas Gauge Quivering???

[darren250r]

I recently noticed that my 98 OBS gas gauge is quivering. The truck has approx 165,000 miles. The gauge moves about 1/32"-1/16" in either direction at a speed that makes it look like a blur.

I suspect that my sending unit might be getting old because the gauge shows that the tank is full for approx the first 1/2 tank, then drops fairly quickly during the time it takes to use up the 2nd half of the tank. I'm not sure if these two issues are related, but I thought it might be worth mentioning.

If anyone knows why my gas gauge is quivering or if it might be related to the accuracy issue please let me know. Thanks in advance.

Darren

[BlackSilvy]

its your sending unit most likely. Happened to me also. But the thing with the 2nd half going quicker. That happens on alot of GM's because the bottom of the tanks are actually narrower than the top.

[hillbilly2084]

The little shaking needle is happening to me also. Awhile ago someone told me that it was a ground. I never check anything because i got use to it, but i would also like to hear what everybody else has to say abour rhis problem...

[darren250r]

Anyone else have any ideas?

Darren

[icemike557]

mine had been shaking for a couple months and then i upgraded my wires (the big 3) and i really didn't notice till a month later that it wasn't shaking anymore, it could have been a bad ground that had gotten fixed with the new wires, don't know if this will help

[Blad]

my dads 97 shakes and moves around and after a new fuel pump assembly, the dealership told us its the actual guage and that you can replace it without replacing the whole cluster.

[occupant]

Well at least your fuel gauge works from E to F, right?

Mine shows a full tank at 3/8 tank. Half tank at 1/8 tank. Empty a hair below E. I'm thinking of sticking a little label that says "F" right between 1/4 and 1/2, and putting electrical tape over the 1/2 and original F. Then it will be accurate, LOL! 40 gallon tank but the fuel gauge movement is like, for 10 gallons!

[Blad]

yeah it shakes but still marks correct. they also told him that the valve on top of the fuelpump to ventilate it was stuck open. but i call BS, how could it pressurize then?!?! maybe its the valve that leads to the charcoal canister?

[98GreenMachine]

Anyone else have any ideas?

Darren

Its the gauge itself thats bad. Mine has been doing the same thing and it didn't change after I had to replace my fuel pump/sender. Mine still reads accurately, it just flutters rapidly as you described. Its possible that your sender is also on its way out, but the sender unit is not causing the gauge to vibrate.

[Blad]

yes, exactly. think about it. i dont think its physically posible that the float on the assembly can move fast enough to make the guage move side to side that fast.

[Kruznlow69]

there have been a few threads on this.. it is the actual gauge in the cluster, i got a junkyard one but never got around to working on it. i ohmed out the motor for the gauge and it read different than the others.. its not the sending unit..

[darren250r]

Sweet, thanks alot guys! Sounds like my guage has some issues. I havn't taken the dash apart on the truck, so are all the guages connected or can they be removed individually?

Darren

[daman1]

Read post #15,

http://www.fullsizechevy.com/forums/showthread.php?t=259246

[claviz13]

Maybe it's scared because of the cost of gas. LOL!

[Kruznlow69]

awesome! glad to finally know what the fix is. i knew it was in the motor in the gauge but didnt ever fix mine.. thanks!

[87Iroc]

My OBS 98 did it and I believe it was the grounding wire on the tank...but I never fixed it. I assume this was it as the grounding tang had come off the tank...and the wire was hanging down...

I'd at least look under the truck to see if it's hanging beside the tank or not...but it sounds like it's a fairly common problem.

[Kruznlow69]

well i got my denali cluster in and it fixed the gas gauge crazy spins but it still quivers/ flutters.. im thinking my harness to the fuel tank is damaged or the bcm.. i traced the signal (on data sheets) at the dealership and it goes through the bcm if i remember right..

[daman1]

if it still quivers that one may be bad as well,check to see
if the needle will move very freely with your finger.

when i replaced mine with one i got off ebay it fixed it all
works perfectly,the needle was nice and tight on the new one.