Vacuum leak affect tune?
09-14-2014, 07:29 PM
#1
Instructor
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Vacuum leak affect tune?
I have a 2004 C5Z that is H/C'd. After getting it tuned I noticed the 1/8" hvac vacuum hose that attaches to the rear of the FAST intake was disconnected. I reconnected it and the car drives abnormally worse. It would hunt for idle and surge a lot more than before. What I am curious about is if the car was tuned with a vacuum leak would fixing the leak cause drivability issues because it throws off the "tuned" fuel trims?
09-14-2014, 08:19 PM
#2
Drifting
do you have the ability to datalog or see what's going on with the fuel trims?
09-20-2014, 03:19 AM
#3
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St. Jude Donor '13-'14-'15
Yes a vacuum leak allows "unmetered air" to get into the eng so it is not making fuel corrections for that air as the ECM doesn't know it's there