hello, i just reciently purchased a use 96 850. on the air box there are two vacuum lines. the bottom one is connected but the upper one is disconected. were does it go. i have looked all over the engine bay and the haynes manual doesn't say. any one know. also is there any mods to get better gas mileage, ie remap the computer. thanks dave.

 

Is the disconnected one light colored or a small black line? The small black one on mine isn't connected to anything, either.

 

yea it is. two volvo mechanic didn't know either

 

http://www.matthewsvolvosite.com/cha...pic.php?t=8018

Check out the vacuum diagrams in there.

 

the vacuum daigram does not show any airbox diagramsin that manual or in the haynes manual

 

One goes to the front where the Fresh air hose goes into from by the radiator. There is a valve under there.
The other one goes over to a valve on the top of the radator.

 

I found where it goes. i read that some volvo's have a wax valve in the air box that controls the flap for the hot air comming off the exhaust manifold. mine has a vaccume hose attachment. rather than replacing it, i just removed the flap to open up the airway. it was a huge restriction. i have more throttle responce now.