94 intake system

[Dark Matter]

i just noticed today (sadly, had truck for over a year now) that the stock "cai" with the intake piped to the grill. it has a tube on the side of the intake tube to the grill, and that tube goes to my exhaust headers. i dont understand why it pulls hot exhaust air into the intake, makes no sense.

 

[sfwjesse]

If i remember correctly, there is a valve in your airbox that is controlled by a temp sensor disc. The temp sensor uses vacuum from your intake manifold to control this valve. When the air is cold, the sensor keeps this valve open, taking hot gases from your exhaust and mixing them with your intake to make the truck run smoother. As things warm up, the valve closes so you draw cold air and dont rob horsepower with hot air.

My vacuum line to the sensor is disconnected, so my truck runs a little rough till it warms up. Someday i need to hook it all back up (previous owner took it off)

 

[BlackDogSociety]

You don't really need it to pull hot air from the exhaust. I took mine off my 94 2.3L and replaced it with a piece of 3" ABS pipe. I also removed the air muffler in the intake tube after the MAF. I get more power and a little better MPG. Check out my mod on youtube at:

http://www.youtube.com/watch?v=gIbIyd1_SnQ

and view my mileage data at:

http://www.neosbiosphere.com/project/mileage.htm

Works great for me so far...