ok well it appears i have a vacuum leak (S4 NA), because when i spray carby cleaner toward the back of the dynamic chamber the engine bogs abit.

I think it may be between the dynamic chamber and the upper intake manifold (UIM), but could it be anything else round the back there before I take it apart and replace the gasket? Are there any other leaks it could be? and its not vacuum lines because i've replaced them all.


thanks!!

 

do you have an aftermarket air filter? I know it seems obvious but sometimes its little things. My car wouldn't stay idling for more than 20 seconds. I looked everywhere, and it turns out it was between my adapter plate and intake hose... Just check every line, every thing that isnt fuel or coolant and maybe you will find your answer. Good luck.

 

nah everything is stock. im pretty sure its behind the dynamic chamber somewhere.. because it only bogs down abit when I spray it behind the chamber, near the firewall.

if it bogs down... does this mean the leak is before the throttle body or after?



thanks!

 

Just to give you guys a heads up. I recently found that my double throttle diaphram is leaking. I keep sraying in that area and thouht it was an intake leak at the TB but its the diaphram leaking internal. Spray the diaphram directly and see what happens? Good Luck! S5 NA

 

ok.. over a year later, my vacuum leak is still giving me grief.
I cannot deal with the surging idle when the motor is cold any longer

Like i said a year ago, I've pinpointed it to somewhere around the UIM/dynamic chamber. It doesn't appear to be the gasket between the two, but between the two there seems to be a bit of rust, where it looks like something has leaked. I'm not sure how relevant this is, as there is really nothing to leak up that far.

The dynamic chamber pretty much doesn't want to come off.. because the nuts on the bolts dont turn.. they just break off with the thread in them.

Is it worth my while removing all the coloured solenoids and vacuum lines and just going crazy with vacuum line nipples plugging up everything I can find? Emissions is not an issue in this case.

thanks

 

http://www.boostpro.net/prodtester.html

you dont have to be turbo to use this. just remove the AFM and attach it to the intake pipe......i have one and its marvelous!!!
this will pinpoint your leak without a hot exhaust manifold since the car dont need to run to test!!

 

If you can pull emissions you ought to, the emissions equipment creates a lot of likely failure points that would cause leaks. Look up 'emissions removal' or something similar, I believe there's at least one good writeup, maybe several, detailing how to do it.

There's also a boost leak detecting tool out there that might be useful. Even though you're NA, I think the tester would still fit into your intake hose where the MAF goes.

Here's an outline on how to make one, adjust the size of piping appropriately...
http://www.vfaq.com/mods/ICtester.html

Ah, here it is. I bought one of these and it's been one of the most valuable diagnostic tools I've ever had.
http://www.boostpro.net/prodtester.html
http://www.vfaq.com/mods/ICtester.html

edit:
jeez 88rxn/a, you beat me to it by seconds lol

 

but really,
it is a great item i posted. i used a black rubber 3 to 4 inch coupler from lowes and since the rubber was soft at 15PSI (what im boosting to soon) it would pop off and sound like a gun. so make sure whatever you use is not gonna slip. cause it scares the hell outta ya...

 

yep I've looked at the various vacuum removal sites/threads
Thanks for the website guys, I might try hooking up my compressor to the intake with an attachment and listen for leaks.

I plugged up all the vacuum lines today.. It idles ever worse. Despite surging, its now really rough. yay!