Fuel guage calibration?

These tanks must be shaped like a funnel! I can get 350+miles out of the top half of the tank and only 150 out of the bottom, then the last quarter of a tank, it seems I can only get 25 miles before it starts begging for fuel!

I know every car does this to an extent, but I would think it'd be quite simple for the manufacturers to calibrate this better. Is this something we can do on our own are do we just have to live with it the way it is?

Run the fuel level to below 1/2 and remove the sender from the tank and make sure it isn't sticking or binding.

Just the way it is, most likely. I suppose you could convert to a capacitive type fuel indicating system like large jet aircraft have for several thousand dollars.

There was an amzing analysis and graph by "gmcjetpilot" that showed the the gauge was in fact perfectly linear, except for the first 95-100 miles before it starts to move. The thread still exists, but unfortunately the graph no longer shows in the thread. I can tell you that after seeing the graph I didn't question the gauge ever again. He did numerous tanks of fuel, recording miles at different set intervals on the gauge. The graph of the results was truly a masterpiece and clearly showed the gauge is linear after that first 95-100 miles. I suggest that if you do the same thing you'll realize the gauge does not require calibration.

Fuel Gauge Accuracy and Linearity

PS: I asked gmcjetpilot to fix the graph image, so maybe it will show up again. It was a beautiful thing!

ksing44 - you are saying we are off only because we get near 100 miles on the tank before the gauge moves? I guess that stands to reason. So roughly speaking, I get 225-ish miles from when the needle leaves the F to the halfway mark. But I still only get 150ish out of the bottom half, and most of that is done on the 1/2 to 1/4 mark.

You point is valid, but I still believe something could be done, if there is indeed some programming that would allow it.

Just thinking back to all the cars I have owned, this VW is by far the worse at this scenario than anything else I have owned. I don't recall if our '06 was the same way or not.

I think the perceived effect is also exacerbated by the fact that reserve is indicated as 1/8th of the tank, so the second half of the tank is actually only 3/8 until "empty" and in reserve. So 3/8ths vs 4/8ths and the added 100 miles before it moves, that's a huge difference between the first and second half of the gauge even though the gauge is linear after it moves. If I had gmcjetpilot's patience and persistence, I'd try to reproduce his result.

PS: I'll add that previous fuel gauges I remember in other cars didn't have large ~300 degree sweeps like this Golf. Typically I think they were comparably narrow sweeps, less than 180 degrees, so a crude measurement by comparison.

My Golf gauge!

on Flickr

My empty to full lines are maybe 80 degrees apart, where yours is more like 270. That doesn't help either.