Hi Everyone,

Just bought my wife a slightly used S (2005 w/16k miles) that has the JCW tuning kit installed by the dealership. Today was the 1st day I got to pop the hood and check all fluid levels, etc., you know the usual you do when you get a new car and noticed something odd. On the JCW intake box right next to the left front torx screw holding the lid down, there is a small (approx. 1/8" in diameter) rubber hose that comes out of the box. I figure it's either a vacuum line or possibly a drain for water. My experience leads me to believe it's a vacuum line. The problem is it's not connected to anything on the other end. Meaning pretty much pointing down to the ground. I poked around to see if it got disconnected by the previous owner or never installed to begin with but did not find any obvious connection points. The car does NOT through a check engine light and seems to run like a champ.

Any ideas?

As this is also my 1st post, I thought I would post a pix of the car. I can also post a picture of the hose in question if that helps.

Thanks....

 

Welcome to NAM Devil. That's a very nice car you've bought your wife.

Now on to your question.... Yes that is a vacuum line that is hanging there. It supplies vacuum to the vacuum motor on the top rear of the air box. When you hit 4,500 RPM that motor opens a flap at the back of the air box. More air goes in & more noise comes out. If you bought from a dealer take the car back & have them hook it up. Even if you bought from a private party the warranty should cover the fix.

 

Thanks for the quick reply. Actually I prefer to do most work myself. I don't trust stealerships. The motor you speak of is top left of the lid correct? If I squeeze my fat fingers behind there should I be able to easily feel the nipple it connects to or do I need to remove the box to get access?

TIA

 

The vacuum line runs to a fitting under the intercooler on the supercharger bypass valve. It's a bear to get to, but can be done.

Here's a link that helped me get mine done.

https://www.northamericanmotoring.co...ght=JCW+intake

Like you I like doing work myself, but if I had to do this myself or could have the dealer do it under warranty it would be the dealer for sure. It was that much of a bear for me.

 

Thanks for the tip. I will check it out tomorrow when the sun comes back. Since I only have about 6 inches of hose coming out of the intake lid, I will have to assume that the other end is within reach? Based on the link you posted, it would seem the end connected to the bypass should be there but it got disconnected somewhere under the intercooler. I guess it's time I get my bearings with this engine compartment. Just needed to make sure that this wasn't a critical line as we are taking it out for our holiday travels and did not want to get stuck in her car.

Thanks!

 

The short vacuum line connects to the front of the airbox. There is a vaccum canister inside the airbox to which the line connects. The vacuum is used to open the cowl intake flap at 4500 RPM. The vacuum diapham, that controls the flap, is on the top back of the airbox. It could be that the previous owner removed the flap and disconnected the vacuum line. If so, the vacuum line should be plugged (probably with cap or screw).

It is a common mod to remove the flap and disconnect the vacuum line. It is also common that the flap, canister, and diapham be removed. John Cooper Motorsports sells a JCW airbox with everything removed and a plate over the hole where the diapham linkage connected to the flap.

 

My guess is that the vacuum line was never attached. If it was & came off you'd have a vacuum leak & a check engine light on. You will be perfectly fine driving your MCS until you get around to fixing the wayward vacuum line.

Yes the vacuum line is a short one. It's just long enough to reach the supercharger valve.

Edit...quikmni has a good point. Before proceeding put your hand behind the air box & see if you can feel a flap in there. No sense going through all the contortions required to hook up that vacuum line if the flaps been disconnected.

Merry Christmas.

 

Mine fell off because the one supplied was a bit short. I replaced it with a line about 2 inches longer. When it fell off the car ran noticeably worse but did not trip the CEL.

 

Thanks everyone. No the flap was not opening. With all your help I got it fixed this morning. Not only was the airbox line disconnected off the "T" at the bypass valve but was also disconnected off the bypass as well and was pointing towards the ground. Once I took the intercooler off and got one of my good halogen lights in there I was able to see the T connector. That was half the battle. Took me another hour to get my bloody hands in there and get everything hooked up. A quick test had the flap opening closer to 5,000 RPM than 4,500 RPM....

I don't know which fluid I lost more of, sweat or blood on this one. Sure not designed to 210+ lbs guys to work on are they?

Thanks to everyone and Happy Holidays!

 

Now you understand why I said let the dealer sweat it.

I found this install pdf for you, but I'm a bit late.

http://motoringfile.com/files/JCWUPGRADE.pdf

Glad you got your JCW intake a flappin.

 

Thanks for that. I already had that document but was too vague visually as I only had the car less than 48 hrs. I figured the quickest way was to remove everything in my way and go from there. Can't say the wife was too pleased when she came out of the house to see a bunch of parts removed from her new car .

I think if it was up to me I would return the vacuum lines to stock and remove the flap but since it's her car, she gets to decide how she wants her car to perform.

Thanks again for your help. Now onto my next task, retrofit with heated seats!