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What the heck are those dang vaccuum switches for?

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I got two vaccum switches up near the firewall on the passenger side that used to be connected. Car runs fine without them, but someone told me that on of them helps the timing advance under certain conditions.......

 

I'd like to know what they are for, and what they should be connected to, if anything....?

  • Author

Sorry, it's an '84 GL Wagon FWD, 1800CC Carter/Weber carb, 5 speed manual.

 

I didn't get much sleep LOL

It could be for your vent settings, the mix and blend doors are operated by vacuume, so without them it may be stuck on "not defrost" which in Washington is rather important.

I got two vaccum switches up near the firewall on the passenger side that used to be connected. Car runs fine without them, but someone told me that on of them helps the timing advance under certain conditions.......

 

I'd like to know what they are for, and what they should be connected to, if anything....?

 

The vacuum switches don`t have anything to do with timing.There is a thermosensor that does though.

 

They should both be hooked to manifold vacuum.Between them,the two switches act like a primitive map sensor w/two different trigger points.

 

Switch #1 tells the ECU to ignore the O2 sensor under certain conditions.

Switch #2 tells the ECU to respond more quickly To the O2 sensor under certain conditions.

  • Author

Well that's just weird! My car lacks an O2 sensor and does not even have a hole to mount one in, yet, there are two vaccum switches for it and the ECS light shows the code for O2 sensor.....Well I prolly needn't wonder.

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