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Guest Message by DevFuse

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Fuel guage probs on 1990 Legacy

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16 replies to this topic

#1 Guest_subaruGX_*

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Posted 04 January 2002 - 04:39 PM

My fuel guage reading has become unreliable and I assume that an electrical connection is failing.

The fuel guage displays the correct level some of the time but for the remainder of the time it shows a level below the actual. Has anyone experienced problems like this?

I'm guessing that there is an electrical connection that is disconnecting and returning a zero voltage to the guage which lowers slowly (due to damping in the guage) rather than dropping imediately to zero. This connection must be going on and off all the time so the guage keeps moving about but never going above the actual fuel level.

#2 Guest_Dylan_*

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Posted 04 January 2002 - 06:11 PM

My '93 Legacy's fuel gauge always reads a little lower than there is in the actual tank. I know I can go at least 290 miles on a tank without the fuel light coming on, but the gauge will read empty at around 250 miles or so.

#3 Guest_Sam_*

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Posted 04 January 2002 - 09:41 PM

This is another common Subaru problem. The problem is the sending unit located in the fuel tank which is part of the low pressure fuel pump. Not sure what car you have, but on AWD cars there are two sending units and they are expenseve to replace. Most people just use the odometer instead of the fuel guage.

#4 Guest_subaruGX_*

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Posted 05 January 2002 - 04:07 AM

ah ... that doesn't sound good. I would rather having a working fuel gauge so when you say pricey what sorta money do you mean? By the way its a 1990 Subaru GX (NZ and Aussie release I believe) Wagon.

If there are two sending units then more than likely its only one of them that is faulty? I may be able to get one second hand but I guess theres no way of knowing if its also faulty unless I test it.

#5 Guest_trayborcret_*

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Posted 05 January 2002 - 01:32 PM

I must admit that the fuel guage on my Legacy is quite pants too! When you fill it to the brim the needle sits just below the full mark for a day or so, it then very suddenly drops to centre position. It'll stay put in the middle briefly, but then near enough drops straight down to the empty mark! It stays there for a coupla days before the light comes on but then it'll only take a bit less than £30 of fuel to fill it (probably about 40 litres or so). I think the tank is 50 or even 60 litres on the Legacy isn't it? So it must still have quite a bit left when the light comes on I think.

#6 Guest_subaruGX_*

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Posted 05 January 2002 - 07:46 PM

My guess is 60. I don't have a users manual but I've put more than 50 in my wagon once and I never let it run right down.

#7 Guest_Commuter_*

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Posted 05 January 2002 - 08:41 PM

£30 for 40 liters!! Ouch! I know you pay a lot more over there, but still... My 97 OB is a 60 L tank.


#8 Guest_Jayhawk_*

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Posted 05 January 2002 - 08:44 PM

You need to replace the sensors in the fuel tank. At my dealer in the USA, they were $50 and $60 bucks each. I had two, you may have one-pull up the carpet and count how many openings into the tank. Easy fix. Relieve fuel pressure, disconnect battery, take out, put in.
NOw I don't have to use the odometer as my fuel gauge.

#9 Guest_subaruGX_*

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Posted 05 January 2002 - 08:47 PM

So you saying I will have to replace both. Price doesn't sound *so* bad. I guess thats about NZ$100 each then.

#10 Guest_trayborcret_*

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Posted 06 January 2002 - 02:22 PM

Yeah fuel in the UK is crazy, but on the IOM it costs even more!! I think it's abou £0.80/litre at the moment so it costs a bit every month to run my dear scooby but it's worth it!

#11 Guest_wrxsubaru_*

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Posted 07 January 2002 - 09:10 PM

some times my fuel gauge, will go to empty when it was filled up, or at a stop it will go to empty, and then go back up, expecaly when it is hot out side 80 90 deggres, it is a 90 legacy awd sedan

#12 Guest_naliberty_*

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Posted 08 January 2002 - 04:34 AM

You would probably be best off to find out what is faulty ie.sender or whatever and get a replacement from a wrecker over there. Parts in NZ from wreckers are SOOOOO CHEAP!!!
so get them from the wrecker!

BTW my fuel gauge hasn't worked at all for about a month and a half, but the fuel light still works. : )

Probably something to do with an AWD conversion and adapting a FWD pump with a sending unit! hehe Will have to go buy the right pump i think! :(

#13 Guest_subaruGX_*

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Posted 11 January 2002 - 12:31 AM

Yea you can always rely on the fuel light. I'll have a nosey sometime and see whats broken then. Might get a shop manual first though so I don't break anything...

#14 Guest_Skizix_*

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Posted 11 January 2002 - 01:14 AM

Hmm...the light on mine ('90 Legacy L awd) went wacky way before the fuel guage did. For a long time now, the light has come on too early (1/4 tank), then goes out around when it should come on, then comes on right at the bitter end. I dunno, maybe still useful, but certainly whacked. Anyway, my fuel guage has recently become sketchy as well. It reads normally 'till very near the end of the tank, but the tank runs out w/ the needle still showing 1/8 or so. Very annoying! (the first time it happened, I assumed the engine had gone belly-up, as the guage showed not-empty. Hitched a ride home. On the tow-mission, on a hunch, I brought a little gasoline and sure enough...no tow necessary).

Anyway, the light and the needle obviously read different sensors, but they are both suspect, from my experience -- be careful out there. As for me, trying to decide b/t fixing all the little stuff or getting a new(er?) car altogether.

#15 Guest_subaruGX_*

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Posted 12 January 2002 - 05:36 AM

Yes I have similar dilema. I would like a project but it all costs money and buying a subby in better condition would probably work out cheaper.

I guess you will always end up fixing the smae problems with the nicer car but hopefully fewer of them...

#16 Guest_Frag_*

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Posted 12 January 2002 - 04:08 PM

I copied this from somewhere. Maybe here, maybe on alt.autos.subaru.
Could be of some help.
«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

#17 Guest_SmashPDX_*

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Posted 12 January 2002 - 04:27 PM

Kick me when this thread is done and I'll archive it. :)

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