Downshift Backfire??
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Downshift Backfire??
Here's the setup, 2006 Nightrain (fuel injected) with a stage one upgrade, python true duals, screamin' eagle intake, and the standard HD stage 1 computer dowload. Almost everytime I downshift I get a nasty backfire after the engine has slowed down a bit. I understand how a backfire happens but I don't know if there is anything I can do to fix it... any ideas would be appreciated.
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Joined: Mar 2007
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From: North Georgia
RE: Downshift Backfire??
If you do a topic search on "decel popping" you will have enough reading for a month. Plenty of references to backfire get included in these discussions.
Basically, I have come to understand that the HD stage 1 download to your ECM isn't aggressive enough. A lot of folks keep (or go back to) stock ECM settings and then add a fuel manager.
SERT, PCIII, FuelPak, and ThunderMax are the popular choices after changing pipes and a/c. I'm sure you already know all this and are simply trying to find alternatives or additional changes to your ECM without adding a fuel computer.
I have V&H BSS & FuelPak (and AN BS a/c) with only occasional decel popping, and an embarassing backfire once in a while. There are lots of variables in combination(air temp, humidity, altitude, engine temp, and o2 sensor inputs, etc.) that makes it challenging for a better breathing engine to run flawless.
All of my poking around on the forum, I have come to worship some of these guys who DO HAVE flawless running motors. This is usually after big bucks are spent on multiple dyno runs.
Good luck!
Basically, I have come to understand that the HD stage 1 download to your ECM isn't aggressive enough. A lot of folks keep (or go back to) stock ECM settings and then add a fuel manager.
SERT, PCIII, FuelPak, and ThunderMax are the popular choices after changing pipes and a/c. I'm sure you already know all this and are simply trying to find alternatives or additional changes to your ECM without adding a fuel computer.
I have V&H BSS & FuelPak (and AN BS a/c) with only occasional decel popping, and an embarassing backfire once in a while. There are lots of variables in combination(air temp, humidity, altitude, engine temp, and o2 sensor inputs, etc.) that makes it challenging for a better breathing engine to run flawless.
All of my poking around on the forum, I have come to worship some of these guys who DO HAVE flawless running motors. This is usually after big bucks are spent on multiple dyno runs.
Good luck!
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Joined: May 2007
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RE: Downshift Backfire??
All good information. I can add that an exhaust leak can make this occur too. I had the problem until I reinstalled my pipes andreplaced the gaskets. The sound completely changed, the backfires were gone and all is well now.
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anubisss
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Oct 2, 2006 11:18 PM
