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Speedy Squirrel Speedy Squirrel is offline
Rocket Scientist
Join Date: Jun 2008
Location: Detroit
Posts: 909
Originally Posted by JFairman View Post
I think it's the sensor for an engine temp idiot light.
The sensor that disables the lambda system in late eightees cars when the motor is cold is in the right side chain case cover.
Left side chain case has the thermal time switch for the cold start valve. It's tied in with the starter motor and has it's own thermal heater to disable the cold start valve so it doesn't flood the motor in case the car won't start while somebody keeps on trying over and over again and again.. until the battery is dead or the starter motor says see ya.
(Edited for the fifth time!)

The one on the right chain housing cover is a switch that opens at ~35C, and connects to the Fuel Enrichment Control unit with a Green/Yellow wire.

The one on the top (the subject of this post) is a switch that opens at ~15C, and connects to the Oxygen Sensor control unit via a Blue/Green wire.

One lets the engine run a little rich on start up to heat up the catalyst. The other one starts the O2 sensor control.

The oil pressure light gets it's signal from a sender (not a switch). It is that bigger thing screwed into the right side tensioner feed line.

The oil temperature sender is near that, but in the block, not the chain cover. It does the temperature light.

The thermo time switch controls the cold start valve. It is in the left side timing cover.

For cars with the fender mounted oil cooler, there is another oil temperature sender on that part that controls the fan for the oil cooler.

OK, I think that is it.

Last edited by Speedy Squirrel; 10-02-2016 at 07:37 PM..
Old 10-02-2016, 06:40 PM
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