How do you fix the fuel gauge?

[BRAD_PADGETT]

I have an 85GN and over the past few years the fuel gauge gets more and more inaccurate. How do you fix this? Thanks-Brad

 

[Brocks GN]

I would like to know as well. I just bought an 86 GN. When I fill it up it reads full and it seems to work fine until it gets to half a tank then the needle goes past the full mark and I can't see it anymore. Sorry if I hijacked your thread

 

[BRAD_PADGETT]

Brockblackz78- My fuel gauge acts like yours. I have to use the trip odometer in order to keep me from running out of gas. Hopefully someone can help us with this problem. This problem would be easily solved if GNTTYPE.ORG was working. I tried a search here on this topic and was not successful. Thanks-Brad

 

[Scott Atk]

The sending units on these cars suck. New ones are expensive so if you're up to dropping the tank you can pull the sending unit out and carefully dissamble it. You'll have to pry back the sheetmetal tabs. Once you get it apart use a pencil eraser to clean the sliding contacts. This usually helps.

 

[BRAD_PADGETT]

Thanks Scott. Where do I buy a new sending unit and do you still have to drop the tank to install a new one? Thanks-Brad

 

[Scott Atk]

Last I heard Mike McCoy had a gaggle of them, but I'm not sure if he's still in the game or not??? Hopefully someone will chime in. I think I heard they were discontinued from GM. Regardless you have to drop the tank to replace it. Its really not that bad of a job, especially if you have a functioning fuel pump to use to drain the tank. Good Luck

 

[James'6]

There is a baffle very close to the sending ass. that is prone to coming loose.It gets against the float arm and it can't work properly.It is not welded in, but held by tabs on the bottom of the tank. This is often the problem.You can put them back with long screwdrivers or tiretools.As I remember ,you don't bend anything to get unit out.You just tap evenly one side to the other. The unit is wedged in very tight,so you may have to tap very hard. Hope this is of some help.I would check this before buying a new unit! James

 

[Jerryl]

Try this thread.
http://www.turbobuick.com/forums/showthread.php?t=173215

 

[QUIP'6']

i did the same thing bent the tabs back and took out arm and cleaned with scotchbrite now my car goes to e and runs out about 4 blocks after also check and see if it ohms right 0 on empty and 99 full almost like a tps reading

 

[MIKES86GN]

my gas werks till about half way then quits, doesnt go past half..but werks fine from 1/2 to full..do i need to follow the same procedure as listed..or do i have to drop the tank???

 

[QUIP'6']

my gas werks till about half way then quits, doesnt go past half..but werks fine from 1/2 to full..do i need to follow the same procedure as listed..or do i have to drop the tank???

wouldnt hurt to check the ohms on it maybe the rod is bent

 

[MIKES86GN]

..how do i test the ohms???

 

[Jerryl]

..how do i test the ohms???

Ohm meter (multi meter)

 

[rtviper]

You can always order a Red Armstrong DP and it comes with the float assembly I believe? Mine was bad and I sent it to RA and he fixed the sending unit and it works fine now

 

[MIKES86GN]

my confusion was were do i test it???

 

[Jerryl]

my confusion was were do i test it???

Well, It will be hard to test from the outside unless you do it on an empty tank and on a full tank. Not sure which wires those are on the outside but not hard to figure out. Maybe someone else can help.

If you take the unit out, just probe the little blue plastic winding thingy ..... on the side where the wire connects and probe the sweeper attached to the float assy.

 

[VadersV6]

My needle will suddenly read lower than it should be. I'll punch the dash and the needle will go back up. That stopped working, lol. Now It will take 150 miles to reach half tank. Makes me think Im getting good mileage, and then in the next 50 miles it drops to just above empty. Piece of crap.
Ill try what you guys are saying when I put the fuel pump in.
What is it about the gauge that would make the needle correct itself when I punch the dash?

 

[Swt_86]

Before you go through the "drop the tank" experience, try this: Pull the fuel gauge out of the dash. Once the bezel is off, you will see it is held in by a couple of screws. Once out, thoroughly clean the two posts on the back of the gauge and the contacts that it slips into. You may find you have solved the problem and you just saved yourself a whole lot of work.

 

[rodman99999]

Gotta agree with that last post. If it's correcting itself when you hit the dash: The problem's not the sending unit in the tank. If you do have to get into the tank, you'll have two wires besides the grey one going to the fuel pump. Touch/connect your ohmeter to those two wires and slowly move the float arm from one limit to the other. You should get a smooth transition from 0 to 90 ohms. If not: clean/replace the unit.

 

[BRAD_PADGETT]

SWT- I pulled the gauge out of the dash and cleaned the contacts and nothing changed. The gauge went up and showed 7/8 of a tank left after 120 miles since last fill up. Not right! I will drop the tank in March and fix it right. Until then I will rely on the trip odometer and refill after 150 miles. I have run out of gas once on the road and once in my driveway. Not anymore. Thanks- Brad