Air Cleaner temp sensor - January 21st 2021 11:04 pm
I know a lot of people just disable the system which captures heated manifold air and sends it into the aircleaner, especially if only driven in warmer climates.
I can say, without a doubt that it affects highway fuel economy on my 1989 B250 when it is disabled.
While coolest possible air intake is desirable when max power is required, that is not true when at 1950rpm at 65mph driving across country.
I found my system operating improperly. The door that blocks fresh air from infront of radiator was always closed, allowing the engine to suck in only heated manifold air.
The temp sensor modulates vaccuum to the modulator which lifts and lowers the door.
There is a Bimetal spring pushing on a pintle. When the spring heats it allows the pintle to drop and less vacccuum reaches the vaccuum modulator and the door drops.
This system is designed to quickly attain keep a ~100F air intake charge, and the engine computer is expecting this. When I disabled mine My normally expected 15.5mpg dropped to just barely 14. I was driving across country and propped the door open 5/8" or so and in warmer temps was able to get as high as 17.4 mpg.
Anyway I bought a Carter TC13 for 18$ on Ebay, as the new old stock part I found was 30$ with 40$ shipping.
They appear identical. I opened up my old one to see how it worked.
The brass nipple which sticks up into the air cleaner can be screwed in or out to dial in the temperature. Inward raises temperature.
The Pintle on mine was stuck so full vacuum always reached the modulator and lifted the door in air cleaner snout cutting off all fresh air always, I dont know for how long, but I will assume since I was never able to get much above 15mpg for the last 3 years.
I Believe the pintle could have been freed up without opening up the sensor. Mine gets restuck as soon as th espring slams it home. I've not played with it much, yet.
I can say, without a doubt that it affects highway fuel economy on my 1989 B250 when it is disabled.
While coolest possible air intake is desirable when max power is required, that is not true when at 1950rpm at 65mph driving across country.
I found my system operating improperly. The door that blocks fresh air from infront of radiator was always closed, allowing the engine to suck in only heated manifold air.
The temp sensor modulates vaccuum to the modulator which lifts and lowers the door.
There is a Bimetal spring pushing on a pintle. When the spring heats it allows the pintle to drop and less vacccuum reaches the vaccuum modulator and the door drops.
This system is designed to quickly attain keep a ~100F air intake charge, and the engine computer is expecting this. When I disabled mine My normally expected 15.5mpg dropped to just barely 14. I was driving across country and propped the door open 5/8" or so and in warmer temps was able to get as high as 17.4 mpg.
Anyway I bought a Carter TC13 for 18$ on Ebay, as the new old stock part I found was 30$ with 40$ shipping.
They appear identical. I opened up my old one to see how it worked.
The brass nipple which sticks up into the air cleaner can be screwed in or out to dial in the temperature. Inward raises temperature.
The Pintle on mine was stuck so full vacuum always reached the modulator and lifted the door in air cleaner snout cutting off all fresh air always, I dont know for how long, but I will assume since I was never able to get much above 15mpg for the last 3 years.
I Believe the pintle could have been freed up without opening up the sensor. Mine gets restuck as soon as th espring slams it home. I've not played with it much, yet.