Vacuum leak in LS2 engine?
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Joined: Apr 2004
Posts: 91
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From: Warrenton Virginia
Vacuum leak in LS2 engine?
Went to a club sponsored dyno day at a local shop last weekend with my 05 coupe. On the first pull the tech told me he was getting some readings that were consistent with a vacuum leak. The knock sensors were retarding the timing and some other things which I cant recall at the moment. The tech was reluctant to push the car throught he rest of the pull and cut it short not wanting to break anything. I pulled the covers and did the normal checks and didnt see anything out of the norm. The car has been running pretty well since I bought it (30Kmiles) except for a rough idle which I guess I just got use to. Any ideas where I might start to look for the leak? I was thinking of using some starter fluid to check for leaks. Your thoughts? Thanks, Steve
Melting Slicks
Joined: Oct 2010
Posts: 2,220
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From: Sugarhill Ga
If you had a leak large enough to affect the idle and timing your "mil" would be on. Yes using carb-starter fluid to find a leak is ok, but I would also suggest cleaning the t-body & getting some MASS cleaner and washing out the sensor then make sure all the clamps on the intake tube are tight. Has the intake manifold been off? or have you done any other engine mods? when did the problems start?
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Joined: Apr 2004
Posts: 91
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From: Warrenton Virginia
LS2 Vacuum leak
Tom,
Thanks for the reply. The mods that I have done so far were headers and exhaust installed, CAI and a tune done while I was at Carlisle last year. After the tune was done it ran well but it seemed to have a persistent rough idle while in drive. The dyno numbers were respectable so I wasnt even aware that I had a problem. I pulled the covers last night and checked the intake around the TB thinking the snorkle may have worked loose or something. Nothing is standing out. The (PC) tune I had done while at Carlisle was pretty quick and I received no background (written or verbal) on what he did. I have been wanting to pull the MAF out and clean it as well as the TB, since I have a very intermittent throttle problem, from a stop I step on the gas and I get no responce. feather the throttle and it responds within a few attempts. Very intermittent but I am begining to think related.
Steve
Thanks for the reply. The mods that I have done so far were headers and exhaust installed, CAI and a tune done while I was at Carlisle last year. After the tune was done it ran well but it seemed to have a persistent rough idle while in drive. The dyno numbers were respectable so I wasnt even aware that I had a problem. I pulled the covers last night and checked the intake around the TB thinking the snorkle may have worked loose or something. Nothing is standing out. The (PC) tune I had done while at Carlisle was pretty quick and I received no background (written or verbal) on what he did. I have been wanting to pull the MAF out and clean it as well as the TB, since I have a very intermittent throttle problem, from a stop I step on the gas and I get no responce. feather the throttle and it responds within a few attempts. Very intermittent but I am begining to think related.
Steve
