Fuel Gauge Fluctuating

I have had this problem for almost a year and can't find out what is wrong. My fuel gauge is flickering very fast. It is almost like buzzing. You can see where the needle is, but if you look close, it is blurry because it is moving so fast. I've never seen this before. Anyone else? Any ideas?

Mine's been doing that. I have a 99 Tahoe 4 door 4x4. Between the driver's side rear door and the rear wheel above the frame, you'll find a bolt. This is where the fuel pump/sender is grounded.

From what I was told, the flickering is a grounding issue. I took that bolt off and then took a dremmel with a sanding drum to the surface. This helped, but didn't fix it 100%. I might try to do it again, but to me, it's not worth dropping the fuel tank again. (I already did that to change the fuel pump. I didn't think about running a new ground then because I just wanted the truck up and running.)

Hardwarz

Thanks Hardwarz,
Do I have to lower the fuel tank to get to the bolt that you are talking about? I think I'll just live with it if I have to drop the tank.

Silver87 said:

Thanks Hardwarz,
Do I have to lower the fuel tank to get to the bolt that you are talking about? I think I'll just live with it if I have to drop the tank.

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No, you don't even have to remove the tire. I removed the bolt and got my dremmel in there without much of a fuss.

Hardwarz

i am having the same problem with my truck. in the near future i will try and drop the gas tank and see if that will solve the problem or i may just try and see if i can reach it without droping the tank.

if you find any more information on the problem i would be most greatful if you would let me know.

Thanks Aaron

2000 Z71 Tahoe said:

i am having the same problem with my truck. in the near future i will try and drop the gas tank and see if that will solve the problem or i may just try and see if i can reach it without droping the tank.

if you find any more information on the problem i would be most greatful if you would let me know.

Thanks Aaron

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From what I was told, if regrounding the tank doesn't work, then you'll probably need to run a completely new ground. To do that, you'll have to drop the tank. Make sure your tank's either completely empty or very close, gas gets heavy.

Hardwarz

thanks i will have to try that when i get back home to where i have all my tools.

Aaron

a mine does that i got 15's my fuel pump comes as an assembly with the float made on to it ya got to replace the whole unit anf yes drop the tank and make sure one thing run the gas as low as you can

i have same problem, tried cleaning ground wire, thought it heled but same thing happening. problem seems to be the sending unit in the tank. i just live with it.

i cleaned the ground point and replaced the sending unit. so the only other place it could be it the gage it self.

My 99 Yukon set for two years with no rear-end - when i replaced the rear-end a few days ago i started driving it again, the fuel hand done the same thing, just viberated constantly... which wasn't much of a problem until i filled the tank up... when i did it, it was fine, for a few miles, than the hand started doing circles.. it had went so far over it was hitting the oil pressure hand.. id cut it off, and just turn the key and the fuel hand would start looking like a fast clock.. and now it is stuck way above full... - So i would strongly reccomend fixing the problem.. And, don't do the same thing i did.. i replaced the sending unit 3 years ago with no problems.. except when dropping the tank, i didn't notice the fuel pressure sensor at the very back on the top... snapped it in half.. now i have a messed up fuel guage, and a SES light because of the pressure sensor...

GMC, my gas needle doesn't read correctly... i was told it was the sensor in the tank... you think the guy meant the sending unit that you speak of? if so... how labor intensive is replacing it?

i always just fill up at the 250 mile mark... but, it would be nice to actually know how much gas i have left...

its not that hard - its two bolts to loosen the straps, (have a jack on the tank if it has gas in it) - remove the front strap.. and MAKE sure to unplug the Pressure sensor - you can do this before taking out any bolts its in the very back of the tank on the top, above the rear-end.. these things break easy... - now back to the tank, once dropped you will need a fuel line remove tool... pop the two lines off of the sender unit, and the two lines off on the front of the tank.. and slide it out, there is a little plate on top of the tank u can remove it with a screw driver and a hammer - it only goes one way.. once that comes off you can pull the sender unit out..

I had the problem before I replace my fuel pump and sender. I still have the problem.

It could be a grounding problem or gauge problem at this point.

Hardwarz

GMCYukalade said:

its not that hard - its two bolts to loosen the straps, (have a jack on the tank if it has gas in it) - remove the front strap.. and MAKE sure to unplug the Pressure sensor - you can do this before taking out any bolts its in the very back of the tank on the top, above the rear-end.. these things break easy... - now back to the tank, once dropped you will need a fuel line remove tool... pop the two lines off of the sender unit, and the two lines off on the front of the tank.. and slide it out, there is a little plate on top of the tank u can remove it with a screw driver and a hammer - it only goes one way.. once that comes off you can pull the sender unit out..

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dealer quoted me 800.00 to fix the sensor... from what you say, i can do it myself. thanks for the info...

Yeah, its really not that hard - the hardest part is removing the fuel lines.. i bought a tool from autozone that is supposed to do that.. it broke on me.. the unit i was replacing i broke both of the plastic nozzles off that the fuel lines connected too...

If you decide to do it yourself, you'll need to drop the tank. To do that, you'll want to make sure that it's as empty as you can get it. I had to use a 5 gal gas can and a siphon. first 5 gal went to my wife's car. 2nd 5 gal went to my friend's car. The 3rd 5 gal sat in the canister along with 2 one gallon canisters. There was still fuel in my tank.

We remove the 2 bolt (with a jack underneath the tank) and lowered the tank.

Remove the ground before dropping the tank along with the vapor lines and fill tube to the back of the tank. Oh... and to drop the tank completely and get the tank out from underneath, you'll want the truck jacked up.... and make sure it's really high off the ground.

My fuel pump came the float assembly (which includes the fuel level sensor built in. I was told by the Chevy dealer that there's there's a good chance that the ground will have to be replaced from the harness to the frame.

It took me several days to do it with help because we could only work on it for 3-4 hours per day and dropping the tank was the biggest pain.

Oh.. have a shop vac ready on had. My ring that held my pump in place was rusted. Once you pound it off using a hammer and a screw driver (and 2 people) use the shop vac to vacuum up all the rust and debris so it doesn't fall into the tank.

I did it myself because I didn't have the $$ to pay someone to do it. I thought, I've replace my fuel pump on my Dodge Intrepid, that was easy. (Not thinking that the Intrepid has an access pannel in the trunk and bolts that hold in the fuel tank, not a locking ring.)

In all, it sucked but saved me $600.00. Now realize, that I've replaced my pump which fixed my fuel pump issue and should have fixed my gauge problem, but it didn't. But I also didn't replace the ground like the dealership told me to either.

Oh yeah.... if the dealership quotes you $800.00 to fix the gauge, make sure you get the quote in writing. $800 to do whatever it takes to fix the gauge. If that means they spend 20 hours and run new lines, then fine. But I've seen people get charged $800 and the problem still isn't fixed because it wasn't what they thought it was (fuel sender, gauge, etc.)

Hardwarz

ya, but, he said his was a 99 i do belive, your not gonna have rust.. unless you go 4-wheeling.. and, i did mine in a little over 2 hours, please remember to unplug the fuel pressor sensor wire first, its at the back of the tank where the filler hose goes in.. dis-connect the filler hose, and the small hose beside it, then, once the tank is dropped, you can unplug the sender unit, and use the fuel line remover tool on the fuel lines - there are 4 lines in total you have to unplug - and i do belive two of them do not require the fuel line remover tool, i could be wrong, they are in the very front of the tank, and the two that do require it are on the sender unit in the middle of the tank, if you have a pair of ramps... you can back up on to them, and slide the tank out of the back of the truck, the ring is fairly easy to get off, and the unit itself just comes up, watch out for the float, you gotta turn the unit to get it out.. but all in all its fairly easy

My 99 Tahoe is from Ohio. We salt the roads here. I see you're from NC. I'm guessing that the rusted ring directly depends on where you're from.

Hardwarz

Ouch salt.. thats not good.. -- we salt the roads in winter... but we hardly ever get a big enough winter for next to nothing.. - i took mine out again tonight... to replace it for the second time - i just used a set of ramps, one under the front drivers tire, one under the back drivers tire.. and up she went.. - the Hardest part of the change, is the stupid fuel lines going into the pump - if you are FOR sure replacing it.. id just go ahead get a pair of cutters and cut the plastic that goes into the fuel lines.. the plastic lines on the pump itself... grrrrr the fuel line remover tool is about useless