Eratic Fuel Gauge Problem

[Scott Stewart]

I own a 2005 STi and have noticed lately that when I fill up the fuel tank
the fuel gauge is not reading up to the "full" mark and get constant eratic
readings thru each tank of fuel. I've heard somewhere where there may be an
issue with the sensor or float in the tank. Has anyone here heard of such
issues? I'm getting ready to call the dealer but I wanted a little heads up
if possible before I call.

Thanks....

 

[abstring]

I own a 2005 STi and have noticed lately that when I fill up the fuel tank
the fuel gauge is not reading up to the "full" mark and get constant eratic
readings thru each tank of fuel. I've heard somewhere where there may be an
issue with the sensor or float in the tank. Has anyone here heard of such
issues? I'm getting ready to call the dealer but I wanted a little heads up
if possible before I call.

Thanks....

Yes, this has tended to be a problem in the later 90s and early 2000s.
My 99 has the same problem, and one of the reasons is that there are
two sending units. This is because the fuel tank is split by the
driveshaft creating two distinct volumes. When one (or both) sensors
misbehave, the readings on the dash will be erratic. The solution to
this has tended to be cleaning the sending unit electrodes that are
submerged in the fuel tank. The alternative of course is to totally
replace the sending units ($$). It has been hypothesized that
corrosion occurs on the electrodes due to detergents present in
American fuel, causing the false readings, but I think that is up for
debate. Hope this helps - you might want to just start using the trip
odometer and reset it after each refueling - that's worked for me.
Good luck.
-Andy