My intake manifold has what appears to be four sensors screwed into its top: front to back is the thermotime switch (part of the cold start circuit), next (right behind the coil) is what looks like a screwed in sensor with a single green (ground?) wire attached, in the third position is the water temperature sensor (which I'm replacing) and last is a screwed in sensor with two wires attached. Can somebody identify what #2 and #4 sensors are?

 

Single green wire = sending unit for the temp gauge on the dashboard


#4 is a temp switch that, in conjunction with the air switching module, operates the air injection pump diverter valve.

The air switching module is mounted on the RH inner fender, near the diagonal engine bay brace. It also has some degree of control over open loop/closed loop switching and (as I recall) the electric cannister purge valve.

Cheers
DD

 

As always, accurate and useful information -- thanks, Doug.