# Who's got a better way to find a vacuum leak?



## Tjax (Feb 20, 2003)

I know I have a leak or two, but I CANT find it with the spray something/see if idle changes method. I know there's a leak, the idle is erratic and I can hear the sucking/hissing noise. Is there a better way to find a vac leak? Orings are new, I've changed or checked pretty much all the vac hoses, can't find a crack in the air boot. CIS-E by the way. Please someone chime in with a killer tip!


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## Coupe__88 (Sep 14, 2003)

*Re: Who's got a better way to find a vacuum leak? (Tjax)*

tape up suspected connections /hoses possibly


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## fat biker (Feb 16, 2001)

*Re: Who's got a better way to find a vacuum leak? (Tjax)*

I generally find that if the leak is so severe that I can hear it, that it is usually not too difficult to find by just poking around - looking and listening.
Here's an example; My LTD quit the other day, starts, just won't make any power. Had it drug home... Changed the plugs, no help. Started it up, pull the air cleaner off, start poking around. There's a check valve, screwed into the intake manifold, a short rubber hose to a pipe. The end of the pipe corroded away completely.
fat biker


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## 85vdub (Apr 9, 2003)

spray it with starting fluid... some say use carb cleaner... most carb cleaner i have used bogs the motor down instead of reving it up... i've always found my vaccum leaks pretty fast with starting fluid...


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## Tjax (Feb 20, 2003)

*Re: (Pred)*

Yeah, I have not tried starting fluid. Good call. http://****************.com/smile/emthup.gif


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## 85vdub (Apr 9, 2003)

Most auto parts stores have it for 89 or 99 cents so its cheap... its also a damn good degreaser


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## Tjax (Feb 20, 2003)

*Re: (Pred)*

Starting fluid worked. Found the leak. Intake boot. Can't see the crack but I know it's there cause the idle goes up when I spray a certain spot. Got another one at home to put on. Thanks! http://****************.com/smile/emthup.gif


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## tkic (Dec 18, 2001)

*Re: Who's got a better way to find a vacuum leak? (Tjax)*

some shops have a smoke machine to find vac leaks, just hook it up anywhere and smoke comes out of the cracks. i was thinking about how to make one for cheap, i'm sure the pro ones are really expensive- cool idea though.


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## 85vdub (Apr 9, 2003)

*Re: (Tjax)*


_Quote, originally posted by *Tjax* »_Starting fluid worked. Found the leak. Intake boot. Can't see the crack but I know it's there cause the idle goes up when I spray a certain spot. Got another one at home to put on. Thanks! http://****************.com/smile/emthup.gif 

No prob glad you got it all figured out... I started doing that on mine after i got it... everywhere i sprayed the car reved a little... so i just bought all new vaccum hose and tried it again and was good to go... Now i just have to get this CIS all tuned up so it doesn't run so rich... 22mpg in a 1.8 8v just sucks


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## Rocco_crossing (Dec 19, 2002)

*Re: Who's got a better way to find a vacuum leak? (EbraketurnGTI)*


_Quote, originally posted by *EbraketurnGTI* »_some shops have a smoke machine to find vac leaks, just hook it up anywhere and smoke comes out of the cracks. i was thinking about how to make one for cheap, i'm sure the pro ones are really expensive- cool idea though.

I bet a fog machine would do it. And I think Target has some for like $20 right now for halloween. I'm not sure they would have enough pressure to push the smoke out though, But it could work!


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## efrum (Sep 26, 2004)

*Re: Who's got a better way to find a vacuum leak? (Rocco_crossing)*

a little tank of propane works really welll...just turn it on and run it along your lines.. its better then the spray because propane can get into all the small leaks seeing as its a gas.


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## secondgen (Jan 9, 2004)

*Re: Who's got a better way to find a vacuum leak? (efrum)*


_Quote, originally posted by *efrum* »_a little tank of propane works really welll...just turn it on and run it along your lines.. its better then the spray because propane can get into all the small leaks seeing as its a gas.

+1


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## JimLill (Dec 17, 2003)

*Re: Who's got a better way to find a vacuum leak? (secondgen)*

propane torch, unlit (same as above)........


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## 84_GLI_coupe (Apr 3, 2001)

*Re: (85vdub)*


_Quote, originally posted by *85vdub* »_22mpg in a 1.8 8v just sucks









I'd be happy with that, I get 16mpg around town taking it easy.








Starting fluid is the one to use, glad you found the leak!! http://****************.com/smile/emthup.gif


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## G60orbust (Dec 14, 2004)

*Re: Who's got a better way to find a vacuum leak? (Rocco_crossing)*


_Quote, originally posted by *Rocco_crossing* »_
I bet a fog machine would do it. And I think Target has some for like $20 right now for halloween. I'm not sure they would have enough pressure to push the smoke out though, But it could work!
 

run the smoke through your leaf blowers intake


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## mistercheeks (Aug 13, 2006)

so if i buy a bottle of starter fluid and spray around some hoses ill find a vacuum leak???


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## The_Hamster (Jul 31, 2000)

*Re: (mistercheeks)*

If it's around the throttle check the idle screw o-ring, and the throttle body gasket out if your new boot doesn't change anything..


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## rickvw420 (Apr 9, 2008)

*Re: (The_Hamster)*

I have an 82 Rabbit 1.7 which I believe is CIS. I am new to all of this.
It starts great but idles high, about 1700 RPM and I believe it's a vaccuum leak. Are there any common problems or parts I should look for? I can't see anything obvious. There is a white breather/diaphragm that has 3 nips on it. The largest is connected to the air intake hose and a smaller one has a vac line attached to it. There is nothing attachted to the other nipple. I tried plugging that port and no change. If I unplug the breather from the air intake hose, the engine quits.
I saw a tip about erratic idle that suggested changing the O2 sensor, which I did. Now it idles much smoother, but still too high.
Any advice would be appreciated!


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## 8v-of-fury (Jul 15, 2008)

*Re: (rickvw420)*


_Quote, originally posted by *rickvw420* »_I have an 82 Rabbit 1.7 which I believe is CIS. I am new to all of this.
It starts great but idles high, about 1700 RPM and I believe it's a vaccuum leak. Are there any common problems or parts I should look for? I can't see anything obvious. There is a white breather/diaphragm that has 3 nips on it. The largest is connected to the air intake hose and a smaller one has a vac line attached to it. There is nothing attachted to the other nipple. I tried plugging that port and no change. If I unplug the breather from the air intake hose, the engine quits.
I saw a tip about erratic idle that suggested changing the O2 sensor, which I did. Now it idles much smoother, but still too high.
Any advice would be appreciated!

I am having this exact same problem... Car starts and idles right under the 1000rpm mark.. but after i drive for a few minutes that idle has crepped its way past 1000 and could be anywhere from 1200-1700 at worst. I don't understand how the leak wouldnt affect the idle... but would after its been revved up and down... Like it will sit and idle for a long time at 1000 until i drive and move through the revs... I will have to get me a bottle of starter fluid.... Need to try some of that.


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## 8v-of-fury (Jul 15, 2008)

*Re: (8v-of-fury)*

I'm thinking that it must be a leak in some metal component of the intake.. Seeing how it's almost as if the car has to warm up before the leak appears to be problematic...
Is there any specific part of the intake that you guys can think of that would warm up and cause a crack to get bigger? I know that the smallest leak really does add to the high idle.. you take on small tube off the intake and it idles like sh!t.. lol
Any ideas? i think this may be why my car is "Ball"-less


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## 4ePikanini (Aug 29, 2007)

i usually just start part by part and remove hose and see if it makes a difference. if it does then the pipe is good. if you pull it and the engine idles the same then that pipe is bad.


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## jorge r (Apr 27, 2006)

*Re: (mistercheeks)*

the test is good also for intake gaskets, a squirt would be beter but spray is what is readily available


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