vacuum leak smoke machine

[azhodge]

so I know I probably have at least one vacuum leak. when I take off the oil fill cap on my 88 there is no change in rpm. seeing back there is a real nightmare. So I ordered one of those paint can evap machines for $65 dollars on ebay. no time to fiddle with this so its worth the money. But what I don't know is where to hook it up. Any advice would be appreciated..

[wareaglescott]

Sorry I cant offer help to your question. I am thinking I need to do the same. Please post feedback how your device worked after you are done.

[dlagerstrom]

These inject the smoke at just over atmospheric pressure. You normally don't need more than 5-10 psi. I don't know the air intake on the Carreras but you need to stick the hose into the intake and seal off around the host. Basically push smoke in under pressure with all known openings plugged to see where the smoke comes out.

Good luck. They are very helpful.

[azhodge]

after reading john walker about vacuum leaks on the brake booster line I was thinking about disconnecting the vacuum line at the brake booster and inserting the smoke there. I saw someone use a rubber glove to seal off the air intake...????

[Gretz]

I did something similar with my mechanic recently. We just disconnected one of the terminal vacuum lines and connected the smoke line that way. I think using a rubber glove to seal the throttle body is a common technique to close that end of the system.

[rwest]

Originally Posted by azhodge

after reading john walker about vacuum leaks on the brake booster line I was thinking about disconnecting the vacuum line at the brake booster and inserting the smoke there. I saw someone use a rubber glove to seal off the air intake...????

That is a good place to smoke test.

[bluelectron]

This is how I did it. The glove seemed to be the easiest.
https://forums.pelicanparts.com/porsche-911-technical-forum/997873-1982-911sc-vacuum-2.html

[azhodge]

Got the $65 "smoked out" ebay machine hooked up and working. found not one leak, but two. I can say that without smoke I had no chance in hell of finding those leaks. Even with the smoke it was a real pain in the ass. Mirror, light and finally HF inspection camera. be careful where you place the can as it gets real hot...

[scarceller]

And where were the 2 leaks?

[jamesrg]

How did you end up hooking it up?

[azhodge]

there were actually three leaks. one on the rubber boot to the air flow meter that was loose. and two vacuum hoses that had rubbed against something.. beware of vacuum hoses that are touching something. I hooked it up to the brake booster line in the front to cover what john walker had discussed. worked well since that is where the battery is to run the smoke machine. warning. the molded rubber hose to the brake booster was in great shape. I decided to replace it since it was thirty years old... until i found out it was $130.. ps. porsche has no record of this hose in the parts department. I found it on pelican...