Slow Car Fast
February 1, 2011 - My little science fair project.
I started by stopping off at NAPA on the way home and going through their Big Book Of Temperature Sensors. Not all of the sensors had information about their resistances, but I was able to pick out a few likely suspects out of the catalog. Two of them were in stock, so I brought them home to test.
First, I used the multimeter to check the resistance between the body of the sender and the stud. The MG part apparently reads 800-830 ohms. NAPA sensor 6046 read 631, sensor 6178 was 273.
Then I boiled some water and risked my tender fingertips by dipping the sensor in it while I measured the resistance. The cooking thermometer told me the actual temperature of the water. At 195F, sensor 6046 read 48 ohms and 6178 read 31. Apparently the MG one should be 31-35 at 190F.
So, 6046 will be fairly close when the car is cold, but read a bit low when hot. However, it's also changing quickly in the normal operating range. 6178 will probably read right about C when cold, and should be pretty close when hot. I'll give them both a try in the car and see how they behave for real, but at least I know what to expect!
entry 548 - tags: science!, cooling