no gas gage fix
 

I have read all the posts, but only one post implied that floats were the source of our low reading gas gages. Has no one fixed the problem? Mine has really gotten bad lately. I thought maybe it was due to cold weather. Since the low fuel light is accurated, what is separate about it from the gage system?

A low reading gauge is more of an annoyance than a problem. All Subarus do it to some extent. The problem is when the fuel level sensor starts to die and your gauge starts reading VERY low from what it should be (that's the case with my 92.....you can fill the tank and it will only read 3/4 full). If that's the problem you are having the only way to fix it is to replace the faulty sensor.



Dave

or let it get to empty as possible and pull the needle and put it on e...

gage sensor
 

So the light uses the same float as the gage? and the light is a simple switch on the float arm? and the gage problem is a resistance issue in the sender?

The "pessimistic" fuel gauge is meant to keep you from running out of gas. Most people will refill as the gauge approaches "E". If it bothers you, think of all that "extra" gas you have when the needle hits "E" as your emergency reserve:)

Isn't this similar to people who set their clocks fast so that they think they have less time to get ready in the morning??



Dave

of course it bothers me when something doesn't work properly. If I wanted a lecture on which way a gas gage should err, if it has to err, I would have gone to another forum.
I am looking for technical information on this forum.
Ken, the aerospace quality engineer

Gid'ay Ken, yes it is a problem that we seem to just put up with. It is not all ways the same. If I fill up for a trip, the gauge will fall to E after about 400K, but I know that I can get 700K to the tank. If I just put 20/30 lts in the gauge will read true right down to the E.

The tank is a two part unit on each side of the tail shaft. There is a resistance unit in each side that are connected in series, the pump draws from the RHS, and the return enters the LHS. There is a venturie pump in the LHS, that pumps the fuel across to the RHS.

The low fuel light is fitted to the RHS tank, and is an negitive temp thermsistor that changes resistance when the fuel uncovers it. It is the only thing that you can rely on.

As to how to fix it:( no idea mate, I just look for 700k, and the light comes on.:cool:

Harvey.;)

All I'm saying is it isn't broken. The gauge probably reads that way on purpose to keep people from running out of gas. Unless your gauge is way off, there is no fix for the sensor. You can reposition the needle, like mentioned before (I think Seraph did this on one of his SVX's). Come on now Ken, when is the last time that "E' really meant empty on any car?:) My friends Chevy reads "E" every time you take a hard corner.



Dave, the OEM Parts Quality Assurance Inspector and, on occasion, the Sanitation Department Manager :p

Thanks Harv.
ok, continuing to ignore the "just forget it comments", I am looking at the schematic and the gage section of the repair manual. The gage should see 100 ohms at E and 10 at F so there must be too much resistance somewhere. I will measure. There are two connectors leading to a single ground point somewhere. I will disconnect and reconnect them, find the ground and clean it up a bit.
I see that the warning light seems to have no relationship with the float on either side of the tank.
Another possibliity might be a bad float on either side.
I am familiar with the English sending units in Healeys and Jensens which seem to last 50 years or so. They use wire wound reisistors with a wiper attached to the float. Might this 12 year old Subaru be similar? If so, corrosion somewhere might cause resistance to increase, I suppose. Since the two resistors are in series, I probably couldn't trouble shoot them in the car even if I knew the original values.

Even if you could figure out which unit was acting up, Subaru only offered these as whole assemblies...pump and all. I'm not sure if you could seperate one sensor from the other without wire cutting and splicing.

Dave

Hmmm...looks like there is a cord that seperates L and R...you should be able to replace just one sensor without much of a hassle. You just have to find a good used one.




Dave

I assumed that one resistor and float was on the left half of the tank and the other was on the right side. Not so?

yes, replace the correct one........... I suppose lacking the resistor value information, it would be trial and error.

just clean the contacts
 

Here is a fix of just cleaning contacts from a Aussie board. Love those Aussies.

http://www.mrtrally.com.au/forums/to...TOPIC_ID=19427