[T3] Fuel gauge

[Jim Adney]

On 1 Feb 2011 at 17:09, Gary Forsmo wrote:

> But you also know that "we" installed your Overflow Kit last summer, because
> the original 90 degree, rubber "pipe" was cracked/broken.  I suppose over
> all that time, evaporation of 3/4 of the fuel COULD have taken place.  Maybe
> the sender float created a bit of corrosion at the 1/4th level.  ???

Seems odd that all the ones I've seen a problem with seemed to have 
that problem at about 1/4 tank. There's nothing special about that 
level in the sender.

> Can I slightly "rotate" the gauge from the back in an attempt to get a
> better electrical contact ... springs to "backside of the dash"?

I'd just wiggle it a bit. There's paint back there, so if you tried 
to rotate it you'd just get onto fresh paint. I THINK part of the 
problem is that the dash padding has shrunk slightly, putting less 
force on those springs. This usually isn't much of a problem, 
however, as you can usually find a place with good contact.

Note that the springs should not be spread too wide. There is a ridge 
there that you don't want to go past, as things will just get looser 
outside that ridge.

> If the sender wires are gently "cleaned" and the electrical connection
> (retaining springs-to-dash) is restored, then I guess the instrument MAY be
> the problem?

It's certainly possible.

> I guess the thing to do is take the car on a 250 mile trip (along with a
> filled, 2-1/2 gallon gas can ... for a partial refill) and see if the gauge
> "sticks" when it gets to the 1/4 full mark.  Road vibration doesn't seem to
> dislodge the needle.  But a "rap" on the dash does.  Curious, eh?

On the ones I've seen, the problem is just at one spot, so that the 
gauge twitches up and down when it's at that spot but works perfectly 
both above and below that spot. If yours just totally stalls at 1/4 
tank, then I'd start to suspect the dash gauge. Electrical current 
meters can get a bit of metal caught in the magnet in there, and that 
can block the needle from going any farther. I've not seen this in 
our gas gauges, but I've fixed it on other meters. It's possible 
here, but must be rare.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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