Originally Posted by
RobertISaar
the autoprom being able to natively datalog a temp sensor is dependant on whether or not it has any bias resistors on the A/D channel.
since a temp sensor is basically a temperature controlled rheostat, the amount of resistance they produce to allow a certain voltage to remain in the A/C circuit, which is how the A/D system measures them.
simple explanation: feed 5V through a 4K resistor to a temp sensor, measure the voltage using a voltmeter between the 4K resistor and the 5V power source, you'll see 5 volts. now measure between the 4K resistor and the sensor, you'll see a different voltage, dependant on the amount of resistance from the sensor. high resistance = higher voltage. lower resistance = lower voltage.
now if the autoprom doesn't have any native pull up resistors, bit more difficult, since that essentially guarantee that there are pull-down resistors installed.