Hey guys, I recently put an intake pipe on and found a vacumn line not connected to anything.
It is off the front of the intake manifold and runs along the front of the engine, at the top, along with the coolant line to the turbo. It runs over towards the intake, but from there I don't see any place for it to connect.
It definetly creats vacumn though when running. I'll post a pic if no one has any ideas.
Thx

 

if you post a pic i can tell you exactly where it goes.

 

it sounds like the vacuum control line to the turbo diverter valve. it you take off the engine mudgard and look up in front of the tubo you will see the DV - black plastic cylindrical valve with 2 large hoses connecting to it. It has a small nipple in the top for a vacuum line. you really want that thing connected as it prevents the turbo from surging, which is a bad thing. and the vacuum leak is gonna play havoc with your ECU and idle mixture. Is your check engine light on?

 

i would put money down that it goes to the dv...BUT, that means someone has bypassed your N249 valve. the hose from your dv should go under your intake manafold to your n249 valve and then from there to your intake manafold.

look at the attached pic. where the blue line is, is where you would by pass the n249 valve. the red line is then where it would then connect to.

hope this helps.

 

The '99 A4 doesn't have a 'N249' valve. the DV is hooked up direct to the manifold.

 

I'll pull the bottom mud gaurd and check the diverter valve. In that Pic my vacumn line is that red one of the intake mani.
I have no check engine light on, but sometimes idle was erratic. I can hear the DV valve functioning.
Thanks for the help

 

damn. i didnt know the 99s didnt have the n249. i hope the diagram still helps you out.

 

Thanks for the help guys, sry i didn't get back sooner. Been workin out of town and the car was off the road. Attacthed that vacumn line to the Dv valve and tested out the new intake, (hps intake pipe off ebay and a KN filter) wow what a difference, so pmuch more pickup. Gotta love the sound of that dv valve.