PCA SDR

My fuel gauge has not been reading accurately. When it gets near 3/8 the low indicator comes on an it starts fluctuating by 1/4 tank. You can see it jump up or down a full 1/4 but it doesn't switch often.

This is an 84 944, anyone fimiliar with this? Can the light or gauge be calibrated? Should I try cleaning the sending unit or should it just be replaced? Or is it the gauge?

George

make sure ground on rear of gauge is clean and tightly connected

It could be the sender going, but Morgan is right to check the ground. On 944's, ground issues are very common.

you can also check the "ground" to make sure some parts havent fallen off. That also happens on 944's

If you pull the unit from the tank and clean everything it usually cures this. After 30+ years, you get gunk on the float guides and wires which often cause a sticky gauge.

Jad wrote:If you pull the unit from the tank and clean everything it usually cures this. After 30+ years, you get gunk on the float guides and wires which often cause a sticky gauge.

Thanks, I've been racking my brain to think of what electrical condition would cause this. But my money is now on sticky float guides! -g

Well I pulled the float from my fuel tank (after first removing the battery ground!). It was a little tricky to clean. The 14"x1.5" cylinder has 3 very small holes leading to the inside where all of the mechanism is. I didn't try to open it. Care should be taken to remove it very slowly so the fuel has time to run out of the holes into the tank, it took a while to drain out. I sprayed carb cleaner into the holes and gently shook the unit. LOTS of varnish rinsed out---evident on the white paper I used to collect the runoff. Looking inside the tank with a flashlight, it was remarkably clean given what came out of the float mechanism, I didn't really see anything, just a little coloration, looked like rust dots. I put some dielectric compound on the contacts and reconnected the wires in the right order when I put it all back together.

So far everything seems to be working perfect, I'm gona note the gauge position and how many gallons I can fit in to check accuracy before I get it real low. I have the feeling it will be pretty accurate, it didn't feel anything like the last (1977) Chrysler float I had my hands on!

Seems something in that cylinder was attracting the varnish because so much came out of there. The funny readings where probably caused by varnish clogging the exit holes; but I cannot explain why the needle seemed to jump up and down 1/4 a tank as it got near empty...

Whoo Hoo!