Gas gauge

[mitsuclipsegsx]

i am sure this is a common thing for the eclipes..... i had a quarter tank left i filled it up(guessing it would be around 12-14 gal) it was only 8 gallons wow the gauges must be really off, is their anyway to recalibrate it or somen??
thanks

 

[wret]

I think vfaq.com has a write up on it somewhere. It seems to be a universal problem. You can adjust the needle on your gauge but that just makes the top end off. Apparently the solution is to put a variable resister in the sensor signal wire and tweak it until you get it right.

...or just live with it.

 

[Defiant]

Yeah, I can't find that gauge adjustment link anymore. Part of it comes from having two sensors, but most of it comes from having a car that's not expensive.

Just learn to drive by the tripmeter instead.

I think the most I've ever gotten into a DSM was a bit over 14 gallons.

 

[redturbo66]

They supposedly have 17 gallon tanks.

 

[luv2rallye]

My '99 GST book says 15.9 gal. but you always have about a gallon that's unusable (in bottom of tank, fuel lines, etc.).

 

[EclipseGST-95]

that might explain why im down to like an 1/8th tank with 200 miles on it....is there some kinda beep warning thing when im almost empty? cus im tryin to push my car to empty to see how many miles i have on the tank...with out actually going empty

 

[Defiant]

that might explain why im down to like an 1/8th tank with 200 miles on it....is there some kinda beep warning thing when im almost empty? cus im tryin to push my car to empty to see how many miles i have on the tank...with out actually going empty

No, they figure if the blinding light on the dash isn't enough to make you look down and maybe glance toward the fuel needle, then you deserve to walk.

Carry a 2-gallon can in the car, and don't run out more than 30 miles from a station.

 

[96TSi_Chris]

Ive gotten used to the look of the orange gas light and the gauge being buried down the bottom. Tends to freak passengers out when your driving down the highway w/ a gas light on and your needle isnt moving from the bottom of the gauge.

 

[DevilSperm]

i put the potentiometer on mine and it works great..it doesnt throw the top of the gauge off at all...i have the link saved somewhere, ill see if i can find it

 

[EclipseGST-95]

i i have never pushed it under 1/8th tank....when would u say the light comes on ...like when the needle hits the bottom line?

 

[DevilSperm]

whos your daddy?



Being the cheap bastard that I am, and wanting to spend money on speed mods
much more than 'convienience' items, I believe I have come up with a simple
fix for SOME 2G fuel gauge problems.

Here's the deal: (Skip to the **** section waaay down for the actual easy
fix directions)

My 95 Talon AWD's fuel gauge is the most inaccurate piece of crap I have
ever seen. On my 1G the thing was dead on, it said E and it meant E. You had
like 10 miles of grace period. The light came on consistantly at about 1/8
tank and was pretty reliable.

On the 2G the gauge is off by around 1/4 tank. I honestly thought that the
2G's had an 11 gallon fuel tank because I would run it down to E and fill
up, 250 miles and 10 gallons every time. Well, one day I was leafing through
the manual, and discovered to my amazement that the tank is actually 16.5
gallons! Woah. So, I put a 1 gallon gas can in the trunk and drove waaaay
past E (Think Seinfeld). Around 280-290 the gas light started to come on (I
used to think it didn't work) and was on solid by 300. So I drove a little
further and chickened out. I filled up at 310 miles and it STILL only took
<14 gallons!

So, this past weekend I decided to pull the fuel tank senders out. Using the
CD manual (Thanks Vineet! a MUST HAVE!) I removed the 'secondary'
sender. It checked out fine, well within spec. Then I *-ahem-* attempted to
pull the main one. Wowee that nut on the fuel line is TIGHT. But I
eventually got it off using two wrenches and a piece of rope to tighten the
wrenches together (Pics coming). The main one was also dead on spec.

Now, stinking of gas, and not happy, I pulled up the electrical diagram for
the fuel gauge and light. In the 2G cars the fuel system is laid out like
this:

In the FWD cars there is a ~16.5 gal tank, one sender/pump/light_sw unit on
the pass side.
In the AWD cars there is a *split* (as in divided, as in yes there are
really TWO tanks) ~16.5 gal tank, with the pump/sender/light_sw on the pass
side, and a second sender/light_sw on the drivers side.

Electrically, the FWD car's sender reads 4 ohms Full, and 112 (+-6)ohms
Empty. The light circuit is TOTALLY seperate consisting of a thermistor
hanging in the tank about 1" from the bottom. When covered in fuel its
resistance is high and the light is off. Uncovered its resistance drops
after a few minutes and the light comes on.

The AWD cars have TWO senders in SERIES. Each reads 2 Ohms Full and about 53
Ohms empty. So, when wired together they present the same resistance as the
FWD car (same dash gauge). The light circuit in the AWD cars is also
seperate from the gauge, and has the same thermistor in the passenger side
tank, but wired in SERIES with a float switch in the drivers side. So the
light ONLY comes on when BOTH tanks are below the set amount.

Here's the fix and reasoning:

Something is messed up because the senders are supposidly correct (within
spec). Together they present the correct resistance to the dash gauge, which
is nothing other than a heavily damped ohmmeter. Reasoning that my tank
reads correctly when full, but gets progressivly more inaccurate as it
empties (reads E when I still have 1/4 tank) I figure the problem is that
the gauge is not SCALED correctly to the senders (in an electrical sense)
there are two possible fixes:

1) bend the rods for the floats. Not a good idea because now the problem
will simply shift to the other end of the scale - ie. the gauge will read
high until it finally hits E where it will be accurate. Maybe. Because
nothing has been done to correct the scale (shrink it) the problem has just
been moved. Considering the trial and error necessary, the fact that the
gauge will still not read right most of the time, the fact that the senders
are in spec, and not wanting to smell like gas anymore, I abondoned this
approach.

2) Fix the problem electrically: The resistance of the senders can be
rescaled and adjusted easily by adding resistance in parallel to the WHOLE
sender assembly. (Both senders in the AWD, or just the one in the FWD).
Using Ohms law and running a bunch of calculations (not detailed here, email
if you want them) I figured that I needed to 'add' 4 gallons to my gauge
when it shows empty, without affecting the F reading (much) by adding a
parrallel resistance of 'about' 380 Ohms.

**** Actual fix for 2G gauge that reads LOW ****
Wanting the ability to easily tweak this, I went to Radio Shack and bought a
1000 Ohm potentiometer (15-turn trimmer, $1.49 email for part no.), I cut
one leg off, soldered on two wires, and spliced them into the harness under
the back seat where it passes into the floor and into the senders. You don't
need to remove the access hatch, just the white 'wire loom' thing screwed to
the floor. You want to put the potentiometer across two wires: Yellow (no
stripe - its the sender 'total' wire on both AWD and FWD) and the big black
(no stripe) one (Ground). Use those blue plastic 'wire taps' (you don't want
to cut the wire, just to wire this across two wires). I left a foot of wire
hanging from the potentiometer so I could let it hang in the rear footwell
for easy adjustment with a screwdriver.

I pre-adjusted it using a multimeter to 380 Ohms before installing it, and
whaddya know, it moved the gauge exactly the amount I wanted. I have been
driving for two days now, and am waiting to run out of gas so I can truly
adjust it accurately. Once I get it perfect I will simply tuck the
potentiometer up under the rear sidepanel somewhere. Not bad for $1.49, 10
minutes work, and not smelling like gas.

BTW, when 'adjusting' the pot, the gauge takes a LONG time to register the
difference (minutes) so go 1/4 turn at a time and drive a while.

If anyone wants schematics let me know, I have clarified the wiring diagram
ones and combined them. I suppose I should post this on the web:

www.geocities.com/capecanaveral/cockpit/6144/talon/talon.htm

Pics soon to follow.
Jeff

 

[HokieDSM]

Your link didn't work.

I think you want this one:
http://www.geocities.com/CapeCanaveral/Cockpit/6144/DSM_Home/2G_Fix_It_Center/flakey_gas_guage.html

 

[Mike98GS-T]

Hey. I followed these directions to a tee... And the potentiometer didn't work at all for me. I had turned it about 7-8 times and the gauge didn't move at all. When we were hooking it up, for some reason the 2 of the clips on one of the wires didn't catch and I had to use multiple splicers to get it to attach. Is it possible that this caused the potentiometer to not work? Let me know a.s.a.p! Please! I have the same problem... and it's just about the last and final thing on the car I need done to make it 100%!

Thanks alot!