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.

 

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!

 

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.

 

mine is pretty much perfect. Mine popped a little before, but that stopped completelywhen I had the injectors changed.

 

Thanks for all of the ideas guys... now I can start researching what to do... sounds like I'll be dropping some cash either way...
Ride Safe!