I'm only on my second tank of gas on my '96 Legacy S/W, but the gas gauge drops to 1/2 tank after only 100 miles. Milage appears normal on fill up (about 24 MPG). I know this car has 2 sending units. Could one have gone bad.

When the tank is full it registers full.

 

BobS

It's a chronic issues with these cars.

My gauge is showing 3/4 after about 80 miles and i get about 360 or so to a tank of 87 gas.

When the gauge is between 1/2 and 1/4 mark, that's when about 1/2 tank was used up.

 

I guess the variance is slightly different from car to car.

The tank straddles the rear diff, so in effect it has two "bottoms" which can confuse the system slightly because the fuel slops from side to side during cornering.

 

Sometimes my tank empty light will come on with the tank half-full after a trip through a round-a-bout Goes out again after a few seconds though.

 

I wouldn't worry about it, just learn to read it for what it is actually saying as opposed to where the needle is pointing!

I gave up on my gas gauge, and just keep track of miles on the tripometer. When I start getting into the "danger zone" (or maybe just the "fretting zone") of 200+ miles, then I fill up the tank and reset my tripometer to zero.

Given the age of your vehicle, it might be the sending units are wearing out. There have been prior posts regarding this. A search should turn them up. People have taken them out, cleaned up the wiper strip, put them back in and extended their life.

 

I think I'm going to have to do mine on my 97 OB next year. It's getting a little irregular when reading the last 1/8th of a tank or so. Low fuel dash light seems to still be consistent however.

 

Commuter

I have had 2 legacies with the same basic problem. Although i usually use the same strategy as others by keeping trip meter mileage I did find that when the tank gets down to true 1/4 or so it starts to read acurately again and when in reserve the fuel light comes on. so unless it really bothers you, you shouldn't have to worry about running out of gas.

yep...my 95 legacy does the same...reads just about full when filled....but drops prematurely fast.......

as nice and better as the new suby's are (I started owning them since 1980)....there seems to be quite a few issues with the newer models....the older ones were amazing

Take the sending units out of the tank, and clean up the resistor pad. Use some fine emery cloth.

 

The resistor pad is the one with all those wiggly black lines on it. They're not supposed to be black. Use a sharp knife blade to clean between the tracks too.

 

The problem is caused by high-sulphur gas. Here in Canada, two brands are notorious for causing problems (Shell & Exxon), others are much better.

instead of emory cloth, i recommend a pencil eraser. it tends to be very gentle and good at removing corrosion from electrical contacts. it takes about 45 minutes to clean both, and works pretty well. don't be surprised if some of the circuit board has been rubbed off by the contact (as mine was). it doesn't seem as though they are the most robust part...

While your cleaning the variable resistor pad with an eraser, pay attention to the float arm's tension spring and washer. I believe that connection transfers the voltage through it up to the wire connection that leads to the fuel gauge. This is where I was having trouble. I recommend checking it before and after cleaning with an ohmmeter. You will able to determine if you have fixed it before you reinstall it. There is a procedure listed somewhere on this board that I followed, and it was very helpful. Good Luck.