Me and a buddy of mines noticed a hose that is not connected to anything on our trucks... This black hose is connected to the bottom of the rubber connector between the throttle body and air filter box.. It runs from the bottom of this connector along the length of the driver's side valve cover.. At the end the hose has an opening and I just wanted to know if this is normal or is it suppose to be connected to something? I wish I had a picture but sorry I don't.. Is anyone familiar with this strange hose and what purpose does it serve?

 

valvecover. top center i think.

 

that sounds like the one to me also.....

 

Is the hose rigid plastic, around 1/2" to 5/8" diameter?

If so, there should be a rubber 90 bend on the end and this should connect to the barbed port of the valve cover. This is the cranlcase vent (into the air intake) for the driver's side.

Herb

 

Also, if it is the small diameter hose. It connects to the rear of the boost actuator valve.

 

Thanks A lot!! I found the 90 bend rubber elbow that sticks out of the valve cover..For some reason the hose slid out from that.. I've lost a lot of power/ boost in my truck.. Could this be a possible reason why? I haven't driven the truck yet.. Could that hose being disconnected cause a vaccumm leak?

Thanks Everyone for your help...

 

no, thats not a vacuum leak or a reason to loose power....

 

It will allow unmetered air into the engine (because it is downstream for the MAF sensor) which can cause a lean condition. The hose won't see (much) vacuum at idle as the port is in front of the throttle butterflies. This would be the equivalent of a "ported vacuum port" on a carburetor, vs. a "manifold vacuum port" which is past the throttle plates. In the "old days" manifold vacuum ports handled things like brake boosters (still do) and ported vacuum ports handled things like vacuum advance canistere. The reason for this is that the throttle butterflies can regulate the amount of vacuum present at a ported vacuum source. At WOT ported vacuum = manifold vacuum, so in that case you would see a vacuum leak.

Herb