using propane to find vacuum leak, any tips?
Race Director
Joined: Jun 2004
Posts: 13,966
Likes: 709
From: WI
I've never heard of this before and would like to know more. Using the starter fluid method, I know you spray it around the suspect leak area. Using smoke, where exactly are you directing the smoke? How does blowing smoke into the TB confirm a leak? If you're looking for the smoke to come out of the exhaust, I can see how that would indicate vac leak. But, how do you pinpoint the source of the leak?
On a related note, my LT idles a bit higher than I think it should, but it idles smooth as a kitten. (Sorry, Sweet90). I'm presuming that a minor vac leak could account for this? The IAC and TB are clean.
On a related note, my LT idles a bit higher than I think it should, but it idles smooth as a kitten. (Sorry, Sweet90). I'm presuming that a minor vac leak could account for this? The IAC and TB are clean.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
That's a new one on me! I guess you're not concerned about any water getting into the cylinders? I also assume water helps to enhance stumbling to confirm location of the leak?
Obviously, it won't smooth things out like propane would.
Between propane and starter fluild, I've always preferred the former. starter fluid can start a fire where propane....The worst thing I can thick of would be the torch lighting. Just be quick to redirect if it does. You can't be quick enough for starter fluid.
Obviously, it won't smooth things out like propane would.
Between propane and starter fluild, I've always preferred the former. starter fluid can start a fire where propane....The worst thing I can thick of would be the torch lighting. Just be quick to redirect if it does. You can't be quick enough for starter fluid.
Not looking to "smooth things out" but, instead am looking for just the opposite: For the engine to stumble and/or white smoke out of the muffler.
Water entering the cylinders is exactly what I'm hoping to find; that'll tell me where the vacuum leak is located.
Other use is to spray water directly into the TB or carb to steam clean the pistons/combustion chambers and valves. That, too, has been around for decades.
Of course nowadays companies want you to buy their "special" stuff to do basically the same thing. You know, "Add "X" amount to the gas and "X" amount to the oil and with the engine running add"X" amount to the power brake vaccum hose"
Jake
Racer
Joined: May 2010
Posts: 315
Likes: 0
From: Central New York NY
Great thread! Found this video on YouTube http://www.youtube.com/watch?v=FfiQ7qWiG-M Doesn't show what smoke machine is being used but shows how it finds leaks. Seems like a smoke machine could be built pretty cheap, but really have to have an accurate air regulator and gauge to make sure you don't put too much pressure into the vacuum lines. I think I'm going to make this my "homemade tool" project for the summer.
Moon
Also found this link about using a shopvac and stethoscope. http://www.bimmerfest.com/forums/sho...d.php?t=398284
Moon
Also found this link about using a shopvac and stethoscope. http://www.bimmerfest.com/forums/sho...d.php?t=398284
Last edited by Moon86; Jul 20, 2010 at 05:10 AM.
Advanced
Joined: May 2010
Posts: 89
Likes: 0
From: Morgans Point Resort Texas
V's Vette Is smoke used with the engine off?
Yes engine will be off for smoke test. You are basically filling intake system with low pressure and smoke which exits out leak if there is one.
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I suppose if you used 'special' smoke, your vette would start thinking that everthing is funny.
Drifting
Joined: Sep 2002
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From: Suwanee,Ga
Safety Car
Joined: Jan 2004
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But maybe some produce smoke, and others produce a mist.
Racer
Joined: Apr 2004
Posts: 306
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From: Cotati CA
Would either of these work? --
http://www.skcinc.com/prod/800-216.asp
http://www.grainger.com/Grainger/wwg...N=0&sst=subset
One thing I found out today...a non-smoker can't really do a smoke test using cigarettes...tastes bad and pretty non-effective!!!
http://www.skcinc.com/prod/800-216.asp
http://www.grainger.com/Grainger/wwg...N=0&sst=subset
One thing I found out today...a non-smoker can't really do a smoke test using cigarettes...tastes bad and pretty non-effective!!!
