Snap quiz on fuel gauge - sensor + general question about gauges

[Pete Masterson]

I note that my fuel gauge is wildly inaccurate, most of the time. I've often tried to guess the amount of fuel a 'fill up' will take based on the gauge reading -- but my guess is usually off by 35 to 50 gallons. I now use a mileage based estimate of fuel use and plan fuel stops based on the miles traveled rather than on the gauge reading. (I use a conservative number so I don't have any nasty surprises.) I note that in practice, fill-ups are more often dictated by selecting states with the best fuel cost, rather than actually running low on fuel. e.g. I'll fill in Arizona before entering California -- or fill in Oklahoma (generally good prices) before passing into one of the surrounding states. Wyoming always beats the prices in Colorado and so on. 

If you think about the shape of the fuel tank (basically a cylinder on its side), the result is a rather non-linear fuel measurement. When full or very low, the level drops quickly. When in the middle range, the level changes very slowly compared to the fuel used. Even a carefully calibrated fuel gauge is not going to be particularly accurate under those circumstances. As I learned in flight training, never trust the fuel gauge.

I note that when my tank is full, the gauge pointer will read just above the full mark on the scale. Unfortunately, there isn't a pin-rest so when the tank is less than full but above about 2/3 full, the sloshing in the tank (due to movement) will cause the pointer to swing way past the full zone and then stick there. If the vehicle is at a full stop for several minutes, the gauge may swing to a more expected reading ... or it might require a bit of tapping on the gauge to get it to un-stick. 

If you were to replace the gauge, I suggest you try to get one that has a pin to keep the pointer from wildly swinging around (and possibly sticking at the extreme end of the travel). However, due to the shape of the tank, I doubt that you'll get much more than a rough indication of fuel quantity with anything more than +/- 10 to 15% accuracy.

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Dec 14, 2008, at 12:55 PM, hippieforever3 wrote:

Since I got my bird, the fuel gauge has always indicated maximum high 

(off scale). I'm not prepared to try and deal with this.

What is the best guess whether it is the gauge itself or the sensor 

unit?

Where is my easiest access to the sensor?

While I'm asking ... part numbers? Can they be serviced? Repaired? 

Refurbed?

I have a few other gauges that are either going to need to be replaced 

or refurbished (speedo and tach). Can they be refurbed? Where?

Regards,

GPSGary

1984FC35