How Can I tell if I have a Vacuum Leak on a LS1?
How Can I tell if I have a Vacuum Leak on a LS1? 
07-30-2004, 08:21 PM
#2
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You can use a mechanics stethescope. Just take off the metal rod part and use just the vacuum hose. Another option is to spray carb. cleaner and see if it affects the idle.
07-30-2004, 08:43 PM
#3
I dont have a stethescope,I knew about the carb cleaner(old school trick)
I was trying to avoid spraying all over my new intake.I was wondering if a vacuum leak can cause low timing at wot on a LS1?I dont know how this computer controled motor is effected by a vacuum leak.is there a way with auto tap ect....
I was trying to avoid spraying all over my new intake.I was wondering if a vacuum leak can cause low timing at wot on a LS1?I dont know how this computer controled motor is effected by a vacuum leak.is there a way with auto tap ect.... Last edited by Pro Mouse; 07-30-2004 at 08:50 PM.
07-30-2004, 09:40 PM
#4
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An unlit propane torch is less messy.
You'd be looking for something like an
abrupt change in idle speed (though IAC
will fight it; you might want to get it
running OK and then pull the IAC connector).
You'd be looking for something like an
abrupt change in idle speed (though IAC
will fight it; you might want to get it
running OK and then pull the IAC connector).
07-30-2004, 11:17 PM
#5
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Originally Posted by jimmyblue
An unlit propane torch is less messy.
You'd be looking for something like an
abrupt change in idle speed (though IAC
will fight it; you might want to get it
running OK and then pull the IAC connector).
You'd be looking for something like an
abrupt change in idle speed (though IAC
will fight it; you might want to get it
running OK and then pull the IAC connector).
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07-30-2004, 11:37 PM
#9
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with a normal tune the fuel trims should be at around zero when youre idling. If you have a vacuum leak they will be high positive numbers and stay there. I think its the STFT's.
07-30-2004, 11:46 PM
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any clue on where to look and how to find my leak after my misadveture on the track spraying? i'm at a loss here. i looked at the manifold where the tube blew out and it looks fine.
07-31-2004, 12:03 AM
#13
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Sometimes vacuum leaks will screw with the MAF readings and the PCM will default it to a locked default number. I've also found out there was a vacuum leak by watching the MAP reading, but its a little harder when you have a cam and lower vacuum already.
08-02-2004, 08:26 PM
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I bumped my idle speed up a little bit and when in gear it will go from 900 to 1200 rpms. when not in gear it will stay at about 900 to 850 but it is little bit rough. could this have something to do with my TC? i'm at a loss someone help?????
08-04-2004, 04:43 PM
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Originally Posted by BadAndy
Yeah, can't you look at the MAP value at idle? I know you can with a Diablo tuner.
