I have a vac leak in my system somewhere. I have found 4 since my idle turned to **** a week ago and fixed them all. By the way, those vac caps and Advanced Auto parts SUCK. They dry rotted and cracked with only 2k on them, f*ck that! I'm sticking to roofing nails zipped tied into short peices of silicone vac lines for vac caps. Everyone I fixed made no difference in my idle, it is around 500-600 and pulses and the usual ****. My timing is on, my tps is set at 1 ohm. I'm fed up so I am removing all of my emissions ****, I am blocking off the ACV, and BAC. I am going to remove the vac rack and modify it. This is what I was thinking. If u remove the vac rack you have to get and -AN line for the turbo coolant line right? And you also have to modify the Purge Valve set-up. Well I was thinking of taking my dremel tool and cutting it up so only the purge line and oil line are left that way I don't have to modify it. Is there anything I haven't taken into account. Removing the ACV and BAC is simple right? Just get the block-off plates and get to work right? Nothing special? Or am I missing something. I'm just so sick of the vac leaks, I can't win for losing it seems like.

 

Do yourself a favor. Only do the ACV since that is the most probable source or your air leak. Make your own blockoff plates.

If your in a big rush, take off the ACV. It's only three small nuts and a hose or two. Get some RTV. Take the acv and block off the only two holes in the acv that can cause a air leak. If you take it off and look at the mating side of the acv, the two SMALL holes are to your right as you look at it. One is somewhat oval in size and the other is located just to the left of that one and a bit up from the oval one. NOTHING else needs blocking off. The RTV should have set up enough in approx one hour sitting in the sun. I give you another forty five minutes to reinstall it, drink a coke and start the car up. The RTV should have set up enough by then.

Apply a film of RTV on one surface of the mating surfaces of the acv and a film of vaseline on the other mating surface to act as a release agent .......when you reinstall the acv. The RTV will help seal the mate and the vaseline will help upon removal of the acv in the future.

Go here for location of the RTV: http://www.teamfc3s.org/forum/showth...threadid=33071

Bac's don't cause leaking problems...on the whole.

 

Don't remove the BAC, save yourself the headache.

 

Whats the headache of removing the BAC, I mean I am already removing the UIM to look for vac leaks ects and take off the vac rack....what's the trouble with it. I am not in a hurry so I'll get the block-off plate and do it up, no sense in keeping the ACV there if the vac rack is gone.

 

But wait, with the ACV gone where does the boost sensor vac line plug into at? I'm confused now.

 

Hmm, on my S4 the boost sensor line connects at the manifold nipple, not the ACV...

Kenteth's not talking about a headache REMOVING the BAC, but the headache you may get afterwards trying to maintain an idle without it. Some guys seem to do OK without it, some guys don't...

 

You're having idle problems so you're removing one of the main thing the ECU controls the idle with... the BAC. Hmmm.

 

The NA MAP sensor is connected to the manifold, the Turbo MAP sensor is connected a nipple on the ACV that goes right through to the manifold.

The MAP sensor can be tee'd into the BOV line, or better, you can drill a hole in the AVC block-off plate and screw a small brass nipple into the same location as the old nipple.

I know, this never ceases to amaze me...

If you have a low idle problem, removing the BAC valve won't help.