View Full Version : Fuel Gauge Erratic Readings

08-24-2006, 09:50 PM
Was hoping someone could help with my fuel gauge problem and could not find anything in the archives;

The analog needle shows a little less than a 1/4 tank when empty (I know becuase I just ran the tank empty to replace the pump). Also, the gauge sometimes starts to float and show a different level, like 3/4 full, or will even point downward!. Happens while driving or even with engine off, key on, it may wander. Will the new pump and hot wire kit I bought from Ractronix fix the guage issue or should I look for something else when replacing the pump?
Any help for new member would be appreciated!


08-24-2006, 11:24 PM
Will the new pump and hot wire kit I bought from Ractronix fix the guage issue

Has to do with the wiper contact area on the sender in the tank being dirty or damaged. Saw a writeup someone did on how they cleaned/fixed theirs, and wanted to get them to allow us to link it to the site. Need to find that...

08-25-2006, 10:12 AM
Ugh. Thanks for the info and fast reply Scott. Any chance you can point me to a picture of the sender showing the contact are you mentioned?

08-25-2006, 05:55 PM
Here it is:


08-25-2006, 11:30 PM
Scott! 87GEEIN!! You guys are freaking awesome. Thanks! Will give it a shot and report back. :yummy:

08-26-2006, 08:30 PM
Another thing is the terminal on the back of the fuel gauge. Mine started doing weird things and it turned out to be this. Removed the pop on connector and cleaned it and the post and it cured my problems.

Maybe something else to check if plan A fails.

08-27-2006, 01:12 PM
Thanks Ian. Will keep this in mind

I removed the fuel tank from the care this morning and hope to resume working on it later.

08-27-2006, 10:01 PM
I'm sure the problem with the sending unit contacts as described by Mr. Keller and 87geeinn's link. The ohm readings I got between the trigger and ground confirms this. I now have 7 to 90 ohms on the float. Installed my GSS-340M fuel pump also. Good thing I rechecked the readings after putting the pump in becuase it showed an open circuit when the float was on empty or full. I took the "wire coil" back out and enlarged the mounting holes so I could move the coil closer to the wiper contact, after jut trying to "bend" the wiper contact over for more pressure. The coil can be flipped to use the "unused edge" but not rotated 180 as the mounting holes are not centered. Seems to work on the bench well now. The sender/pump is now in the tank all I have to do is put the tank back in and hook up the hot wire kit. Will report out when done. Thanks again.

09-01-2006, 09:43 PM
Well I finished installing my new Walbro fuel pump, hot wire kit, and a new in-line filter. The GN seems to start up quicker (less cranking), and holds pressure well. I put 2 1/2 gallons in and fired it up. The gauge reads around 1/8 full at this point. When I filled it up, the went to Full. So an "empty tank" is around 1/8 full on the gauge. Good news is the gauge is nice and steady; no floating around or burying the needle past horizontal. I plan on living with this. Next time I think about pull the tank (years..) I'll think about trying to find a new sending unit or parts. Thanks to everyone for your help.

Oh, the factory regulator was reading 43psi at the rail with the vacuum hose off. I can't get readings while driving as the hose on the gauge is too short, but I used to have a Kenny Belle adjustable regulator. I was going to put it back on, but the washer on the nipple that goes into the fuel rail seemed too brittle, and there was rust on the nipple, so I decided not to put it in. Does anyone know if I can get a rebuild kit for this regulator?

09-02-2006, 02:37 PM
Well, 18/8= 2.25 gallons. I'd say that's pretty darn close to being accurate. Not sure you can expect better.

Are you talking about the O-ring, or the plastic behind it? The O-ring is a standard fuel system part. Should be available anywhere. The plastic piece should be pretty standard as well. However, I'm not sure of its availability.

The KB regulator is blue, correct? It should be rebuildable. I'd try contacting KB first. However, other sources may be able to help.

09-03-2006, 03:27 PM
Thanks Keller. I thought the tank held 17 gallons; I put in 2 1/2 from a can and then 14 1/2 from the gas station... Maybe there is 1 gallon that the in the tank somewhere behind the "baffles" or I could have squeezed in another gallon at the pump. Oh well.

I sent an e-mail to Kenne Bell to see if they have a rebuild kit for it. (Yes, it's blue).


09-03-2006, 07:09 PM
Even if you drain the tank until the pump starts to sputter there will always be about 1 gallon of fuel in the tank, as you can tell when you drop the tank.

09-03-2006, 09:52 PM
87GEEINN; I used clean rags to wipe clean the inside of the tank after I got the sending unit out, so I will have to assume the remaining gallon must be behind the baffles. Thanks for the link!

09-15-2006, 04:02 PM
I now have the KB adjustable regulator on my car. Went to 2 auto stores and 2 GM dealers looking for teh O-ring and the plastic part behind it. The o-ring comes in a kit, with the O-rings for the 6 injectors (12 blue O-rings) for $20.00. Went through my old injectors and used one from there. The plastic ring comes with the regulator. KB never responded. I took the metal shaft/tube that the plastic piece and o-ring sit on, out of the regulator and wet sanded the rusf off the surface. The regulator still holds pressure and works. Thought some of you may want to know about the O-ring search.