AFR Oscillation off idle

Tuning concepts, methods, tips etc.

Moderators: jsmcortina, muythaibxr

Post Reply
swiftmkiii
MS/Extra Newbie
Posts: 9
Joined: Fri Jun 21, 2013 8:32 pm

AFR Oscillation off idle

Post by swiftmkiii »

I haven't posted much, but have been lurking around for about 18 months. I am relatively new, and have not begun to get into the more advanced tuning.

I have an MS2 3.0 with the 3.3.2 firmware. I have a consistent issue with AFR and load oscillation off idle, or more accurately, slightly on throttle. I have noticed the oscillation most often after a shift to 2nd and to 3rd under much less than spirited driving conditions. The attached data log shows the same oscillation as the motor loaded up as I exited out of a cloverleaf.

Could one/some of you guys take a look at my data log and tune and see if you can find what I am missing.

Thanks,
Jeff
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

Re: AFR Oscillation off idle

Post by Matt Cramer »

Looks like an O2 correction overshoot. Try setting the EGO controller authority to zero and tuning the fuel table to better hit your target AFRs in that area, then you can turn it back on. The more accurate the VE table, the less O2 correction driven oscillation you're likely to have.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
swiftmkiii
MS/Extra Newbie
Posts: 9
Joined: Fri Jun 21, 2013 8:32 pm

Re: AFR Oscillation off idle

Post by swiftmkiii »

Thanks, I'll give it a try
swiftmkiii
MS/Extra Newbie
Posts: 9
Joined: Fri Jun 21, 2013 8:32 pm

Re: AFR Oscillation off idle

Post by swiftmkiii »

Thanks for the tips.

I turned off EGO correction, tuned on a warm day, then set EGO authority to 12%. No more oscillation.
Post Reply