Carrera Head Temp Sensor - Resistance readings?

[Steve W]

With the talk about single wire head temperature sensors being the cause of different fuel injection problems on the 84up Carreras, I am trying to diagnose if my single wire sensor is or has gone bad. I am reading 3700 ohms from the sensor on a cold motor (about 45 degrees F) to 80 ohms on a warmed up engine. Does anyone have any knowledge about the proper impedance measurements from the head sensor to determine if it is defective or not? Perhaps if not, maybe someone could give me what their sensor reads cold and hot for comparison. Also, does anyone know what goes bad in a DME relay for it to cause problems? Do the contacts inside burn up or what? Thanks for any help.

[stlrj]

There's nothing wrong with your sensor internally, but a design problem where the threads of the sensor body are used to make the ground which becomes unreliable in time instead of a separate ground wire as in the later style.

Joe

[Thomas Owen]

From Bently:
32 deg. 4.4 - 6.8 kohms
60 to 85 deg. 1.4 - 3.6 kohms
105 deg. 1.0 - 1.3 kohms
175 deg. 250 - 390 ohms
212 deg. 160 - 210 ohms
265 deg. 90 ohms

Good luck,

[Steve W]

Joe, Thomas, much thanks. Based on those readings, seems like my sensor is fine, so I'll leave it alone.