ECU Tune
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Joined: Feb 2016
Posts: 76
Likes: 2
From: Knoxville TN
ECU Tune
I have a 2004 C5 Corvette with a SLP exhaust and Blackwing induction filter. I get a bit of exhaust popping on deceleration that makes me think it is a bit lean. Would I benefit from a custom ECU tune?
Melting Slicks
Joined: Feb 2001
Posts: 2,804
Likes: 358
From: Northville, MI
Unless you use a scanner and run a log file you will not know for certain, the Blackwing will not change the fuel mixture enough unless you replaced the accordion bellows to the TB. The scan/log would show if it changes enough to cause the decel to go lean. The smooth coupler lets more air get to the TB but is goes at a slower speed causing the fuel mapping to give less fuel. The PCM will correct for slight changes over time but if the fuel trims exceed 5% +/- it will still run a little rich/lean and more noticable on decel.
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 479
From: OK
It looks to me like there are several variables that cause popping and they all affect the severity of it... one that hasn't been mentioned is the CATS...
actually the issue is NO CATS not CATS to clarify...
actually the issue is NO CATS not CATS to clarify...
Last edited by 73Corvette; Jun 29, 2016 at 01:33 PM.
Drifting
Joined: Oct 2002
Posts: 1,774
Likes: 66
From: SoCal
Another reason for the popping on decel is the DFCO (Decel Fuel Cut Off) Algorithm in the tune. I have a A/F gauge in my car and see it trip on decel. When the car gets fuel again it pops out the exhaust. Only happens in certain situations and usually decel at a higher RPM, but it will cause popping when it activates.
