Vacuum leak effects on tune.

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Jul 10, 2007 | 10:45 AM

1hotls1

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From: Sibley, La

Vacuum leak effects on tune.

During a recent dyno tune, the car made awesome power but on the way home I realized I had a bad vacuum leak. After fixing the leak, the car is down on power. My question is, could tuning with the vacuum leak be affected after the leak is stopped? The power reduction was pretty significant or I wouldn't even worry about it.

Jul 10, 2007 | 10:51 AM

SSpdDmon

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From: Commerce Twp, MI

Vacuum leak = unmetered air entering clyinders = lean condition

Plug the leak and the AFR should richen back up. You're probably running rich.

Jul 10, 2007 | 12:58 PM

JoeyGC5

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From: St Joe, MO

With the gentlemen above

Jul 10, 2007 | 01:09 PM

1hotls1

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From: Sibley, La

Probably so, its not smoking but smells a little rich. I just wouldn't have thought the power loss would have been so noticeable.

Jul 11, 2007 | 12:54 AM

1320FEVER

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From: Houston

too rich

Jul 11, 2007 | 11:13 AM

KRAZY K 2000 TA

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From: Stockton, NY

of course your rich now you fixed the vacuum leak stoping the extra air from leaning it out,did you have it tuned with the vacuum leak if so it will need to be done again

Jul 11, 2007 | 01:38 PM

1hotls1

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From: Sibley, La

Yea, the leak wasn't noticed until I tried to turn on the a/c on the way home. I guess we'll retune it next week and see where the power went. How much can you lose by running rich? We also had to pull timing due to some knock on the dyno. Now that the vacuum leak is gone, maybe the timing needs to be adjusted. Thanks for the responses.

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