[ULTM8Z]

I'm going to attempt to take this to the next level...

I think I have a poor man's solution to "averaging" that late models use and it's diabolically simple.

I found that if I disconnect the signal wire the gauge goes to "Empty".

However, if I disconnect the ground from the sending unit, the gauge holds its position, and it returns to normal function when re-connected.

To test that, I jacked the back end of the car up, initialized the gauge, then disconnected the ground. I then re-connected the ground and lowered the car, at which point the gauge returned to the straight-and-level reading.

What this means is I can have the gauge stop reading the fuel level when going up or downhill and then start reading it again when back on straight and level ground. Automter's built-in buffer circuit is already enough to prevent the gauge from reacting to short term transients.

So all I need to do is interrupt the sender ground with a tilt-switch. I can double stick tape the switch to the top of the fuel tank (using heavy duty tape) and the orientation of the switch follows the orientation of the tank.

Jacking up the back end of the car with a level, looks like a 5° angle is worth about a 1/8 tank of needle movement. A 10° angle is worth about 1/4 tank.

Although in real world driving, the response time of the switch is a lot faster than the change in terrain and the resulting gauge reaction (which by Autometer's buffer circuit design, is extremely slow).

So it may be the case that the switch detects the change in vehicle angle and deactivates the gauge before the gauge can fully react to a particular off-level angle.

They sell bi-directional programmable versions of tilt switches, so I may get one of those and experiment with different settings. The temp ratings are very high too, so I can probably safely mount on top of the fuel tank.