I believe it is the sensor for the cold start injector.
ejm
May 8 2013, 01:12 PM
The sensor on D-jet in '71 was a thermoswitch. If the temp was low enough it would supply ground to the cold start valve which would spray as long as the starter was engaged. Later they went to a thermo-time switch which would cut the ground to the CSV after cranking for around 10 seconds. This was to prevent flooding on engines wouldn't start.
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