I believe the ECT sensor is an inverse resistor; as it heats up, it's resistance drops. Theoretically, there are only two possible problems. The first is that the sensor gets gunked up or corroded; I believe that this will only slow the sensor's function, or change it's values (ie, make it report it colder or hotter than the engine actually is; both are possible). Second, the wires can become corroded or the sensor disconnected. If the engine doesn't see the sensor, it defaults to the lowest temperature (I believe -70F), which means the engine runs really rich.
There are set values for the resistance at certain temperatures. The table is in both Haynes and Chilton; if you don't have the manuals, I can scan it for you.
Edit: What the heck, here's the table. If you want to check to see if it's working, just dunk the thing in water at a certain degree and measure it's resistance. You can consider it ok if the numbers are similar.
There are set values for the resistance at certain temperatures. The table is in both Haynes and Chilton; if you don't have the manuals, I can scan it for you.
Edit: What the heck, here's the table. If you want to check to see if it's working, just dunk the thing in water at a certain degree and measure it's resistance. You can consider it ok if the numbers are similar.
