Race Technology

Any idea how to measure the signal coming from the standard fuel sensor on my DL1 ? There are three wires, +12v, ground and a signal wire.

There seems to be a voltage coming from the actual level sensor and a resiatance going to the fuel gauge (after going thorugh a "box of tricks").

First, I would determine if the DL1 can be attached without affecting your current fuel gage. To do this, you will want to splice into the signal wire and attach that to a 12V input on the DL1. Verify that your existing gage doens't change (be sure to give it a few minutes).

What you are doing is letting the existing harness supply the 12V power and ground, and you are just reading the resulting voltage at the signal wire. You will need to determine the voltage that results when the tank is full and empty in order to create the calibration equation.

Good luck!

David is right.

Also, you will probably want to smooth that signal over a pretty long time constant, most senders "slosh" quite a bit so most fuel gauges are heavily damped.

Tnanks guys

I had a good look at the existing standard gauge and noticed a nice little pull resistor between the 12v and sensor signal. I presume is converting the resistance to a voltage.

To help me calibrate I have re-attached the std gauge and tapped into the sensor signal with a voltmeter for the time being. I will take readings every 1/8 of a tank which should give me enough data to calibrate with.

I have noticed the sloshing even when rocking the car from side to side. I don't suppose a capacitor would be useful in filtering the signal over such a long time... I'll make do with sampling at 1 or 1/2 Hz at and apply a moving average over 30 seconds or so.

I suppose the forthcoming Dash 2 has the facility for displaying a calibrated fuel level and low level warning light ?