Join Date: Mar 2002
Location: Austin, TX, USA
Go to radio shack and buy a 500 ohm variable resistor. Rig up a spice to stick it inline temporarily. That will give you a way to find out if it will work or not. The linear resistance will essentially offset the reading, but not scale it.
Keep in mind that temperature guages are not linear. The sending unit is a non-linear resistive temperature sensor. So the guage face isn't linear either.
If this is a factory guage, there may be a shunt resistor bolted accross the terminals on the back. If so, you may be able to get another value to calibrate it.
Measure your sensor's resistance at normal outdoor temps. Then drop it in boiling water. Once it's boiled a while, measure the resistance. Write down the two values. Then use your 500 ohhm pot to simulate those resistances while reading the guage. Adjust the pot until the guage reads appropriately (like 212*). Take the difference to estimate the series offset.
[ 08-13-2004, 02:51 PM: Message edited by: dnult ]
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI