Gas Gauge

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My 95 Legacy L sedan gas gauge has been acting up. It reads about 1/4 tank less than what is really there. I have heard this is not an uncommon problem. I did see someones site that has a fix for this. I can't seem to find it anymore though. The last time I was at the dealer, mentioned in my last post under "97 clutch", I asked about fixing this. They gave me some OUTRAGEOUS price because they have to REMOVE the gas tank. Just didn't sound right so after further research, I found that it can be accessed from under the trunk lining. If anyone knows a link to this fix, I would greatly appreciate it. I have been doing the "odometer gas gauge" trick for a while but since we are supposed to get a good snow today, figured I would go "play" for a while and then tackle this project. Thanks!!!

[Guest Frag]

Found a while ago on alt.autos.subaru I think.

« Since I have seen lots of complaints posted about the fuel gauge senders for '95 Legacys of all types failing (check out how many at dejanews!) and have not seen any posts about how easy it is to fix, I thought I would post my experience. I had to get a car last weekend (broke my left foot, can't use the clutch in my usual car...) and got a '95 Outback wagon, in part because it is very similar to my wife's '97 so anything I learn from it has double application... The only thing really wrong with the car, I got it pretty cheaply, was that the fuel gauge was not working right.

First of all, kudos to Subaru for making it so easy to get to the senders! On most cars I would have to drop the fuel tank, but this has plates screwed down in the luggage space that open to uncover ports in the top of the tank. (There is one sender on each side of the car for the AWD cars, where the tank goes up over the drive shaft so has a low spot on each side, just one on the right side for the FWD models. The one on the right has both the in-tank pump and a sender, the other just a sender. The two senders connect to an electronic box that averages their output.)

After you open one of the ports you can take out the sender pretty easily: The one on the same side as the pump has to be unscrewed from the pump to get it through the port: Don't drop the screws in the tank!

Once the sender (the two are almost identical) is out on a bench you see a standard float on an arm, moving a contact along a resistor pack on a ceramic printed circuit. The problem turns out to be the connection between the moving contact and the wire off to the outside world. The wire connects to a thin brass piece, that has a phosphor-bronze spring pushing against it, the other end of the spring pushes against the moving contact piece. Between the brass piece and the moving contact should be less than 1 ohm, was infinite on both of my senders no matter how I wiggled the float arm around. The metals had just gotten oxidized. The float is held in by a push-on nut. It might be possible to get that off peacefully, but I was afraid of damaging the mechanism so I hit it with a Dremel and took it off. It is then pretty easy to disassemble the float and contact assembly: Look out for a small plastic pivot piece that the float arm goes through, you not only need to be sure not to lose it you also have to either keep it in position in the plastic body or else later on you will have to rotate it to drop exactly in to place. I used fine silicon carbide paper to clean the surfaces of the two brass pieces (moving contact's arm and connection to outside world) and also the two ends of the spring, put it back together, good connection in all positions of float. The only remaining problem is to hold it together: If you were able to remove the push-on nut you may be able to reuse it. I got a roll pin at the hardware store, one of those little pieces of steel that is not quite a tube because it has a slot down one side, designed to be driven into a hole. It has a 5/32" outside diameter, was about an inch long, and the inside diameter was just too small to fit over the float arm which is about 0.1" diameter. I cut a little ring off of it with the Dremel, forced the ring over the float arm just like the original push-on nut had been, and it was all done but reinstallation. I did both sides, the gauge works perfectly.

This car has 90K miles on it. If I need to do this every 90K miles that will be OK. A more permanent fix would be to take some very flexible wire, e.g. litz wire, and connect it between the two sides so that it flexes with motion of the float. It will have to live in gasoline, so don't use wire with much insulation but rather route the wire so it can't hit anything it should not connect to. I think this would be pretty easy, should last longer than the resistance element would.

Bob Wilson »

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Thats what I was looking for!!!

 

Thanks!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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Well, it took less than hour and if I knew it was going to be this easy, I would have done it months ago!! Before starting, my gauge read just above empty. I knew via my mileage that I should have a little better than 1/4 tank. Once done, I let it run for a while and when I looked, it was at just over 1/4. I went to fill up (and play in the snow a little bit), the gauge went to the full mark, ON THE NOSE!!!

As soon as I pulled the unit out, the problem was clear as day!!

I did snap a couple of digital pics but I have no clue how to post them. If someone wants to see them, just give me a shout at: sydfloyd@blazenet.net and I will e-mail them to you. (or if someone else wants to post them?).

Just a couple of notes to the procedure listed above. 1. Don't forget to unhook the battery!! BAD time for sparks!!!! 2. I didn't remove clip that holds the float arm. I wasn't into the fight today! Worked out without doing it anyway. The key here is to make sure you get the contact areas clean as this contamination is what the whole problem is!!! (the one pic shows the oxidation buildup before I cleaned it) 3. The unit comes out easy if you just turn it slightly counter-clockwise.

Good Luck!!

[Guest ShawnW]

www.ultimatesubaru.org/Ma...sender.htm

 

Above is the location on the Ultimate Subaru Repair Manual where the repair photos are hosted.