Exhaust popping on deceleration

[Rich Z]

Since I had the STS twin turbos installed, one of the things that bothers me the most is the very loud popping from the exhaust on deceleration. While kicking around on CF, I found this post which sounds intriguing...

A while back there were several threads about FI surging and/or popping with some setups and most commonly the Magnacharged A4 with the cruise control on going down hills. Well after getting an Hptuner and spending a lot of hours playing with my DFCO settings, TC lockup settings and datalogging I finally figured out what my problem was. It turns out that my injectors were misfiring at very narrow pulse widths. It appears that for emissions reasons GM puts a nice lean spot between 1200 and 2800 rpm in our Default Injector Pulse Width Table which is too lean for the bigger aftermarket injectors to cope with. So if you still have a problem with popping after a header install or surging down hill with the cruise control on and changing DFCO or your TC settings did not completely fix it then try this out:

So go to your Default Injector Pulse Width Table and raise the values between 1200 and 2800 rpm to match the rest of the table. In my case on my 2000 C5 I set my entire table to 1.277. That fixed all my surging and popping and my gas mileage improved a little too and thats with the DFCO completely turned off.

INTHERED

Any comments from those in the know about such things? FRC Tom? Is this something I can do myself with my own copy of HPTuners without mucking up something else? Or can you make the adjustment and send me the file?

Thanks!