Fixing fuel level sender, '95 Outback
Robert L. Wilson
'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
NorwoodNat
(after I paid them $72 to diagnose it). My 98 Legacy wagon is a so-called
California emissions car, covered for the sensor for 36 months and 50,000
miles. My wagon was 38 months old and had 45,000 miles on it. Subaru won't
repair it under warranty. Actually it was the sensor unit that was deemed
defective but the service manager said that they replace the whole sender
unit. Interesting that these sensor-sending units seem to be a significant
problem.
"Robert L. Wilson" <wil...@math.wisc.edu> wrote in message
news:9kvhhl$asi$1...@news.doit.wisc.edu...
Gml...@scvnet.com
NorwoodNat wrote:
>
> Golly gee! Norwood Subaru in Norwood MA will fix mine for just $430.00,
> (after I paid them $72 to diagnose it). My 98 Legacy wagon is a so-called
> California emissions car, covered for the sensor for 36 months and 50,000
> miles. My wagon was 38 months old and had 45,000 miles on it.
If it is considered part of the emissions system (I question whether a
fuel sender is, but what the heck) the warranty is 5-years, unlimited
mileage. That's a federal requirement, IIRC.
NorwoodNat
mentioned repairing the unit, only replacing it.
<Gml...@scvnet.com> wrote in message news:3B744BC8...@scvnet.com...
Lost-in-space
gauge...that fixed the problem at 40K, Subaru picked up the bill
Gary
"NorwoodNat" <norwo...@worldnet.att.net> wrote in message
news:Lt9d7.5237$Ki1.3...@bgtnsc06-news.ops.worldnet.att.net...
Wayne Dohnal
<wil...@math.wisc.edu> wrote:
[most of original article snipped)
> The two senders connect
>to an electronic box that averages their output.
Not exactly. The two senders are just in series with each other and
the connect to the fuel guage. Of course, that does give something
approaching an average result.
>The problem turns out to be the connection between
>the moving contact and the wire off to the outside world.
I cleaned the contacts on my senders some time ago, although not as
thoroughly as you did. The problem cam back after a few months. Next
time, I'm going to try soldering a loop of flexible wire across the
moving contact.
An irony here is that the wiper arm and contact part of the sender
looks like its pretty well built, but the simpler moving contact part
doesn't work worth a hoot.
Wayne Dohnal
(email adr is spam-protected)