AFR Learn maxing out negative
It was 70 over the weekend so I got a few miles on the new tune. Still locked in at -35 AFR learn % @ idle. However, it’s dropping into the -20’s while driving. Seems like a good thing.
Still waiting for time to put in a hotter thermostat. Hoping that will drop the idle AFR learn.
Please, stand by...
A hotter thermostat will correct some tuning. The system must see over 170....
I'm bringing up an old post here, but am having the same issues. I bought the 600hp non-PA system and in line fuel pump master kit. It's maxing out at -35.2%. The engine makes in the 13-14 in vacuum range, so I had it originally set to the cam 2 profile. After reading this post, I changed it to cam 1 and it's still maxing out negative. Here is a log if someone would be so kind as to give me some advice on what's going on.
https://www.dropbox.com/s/18otbziew69fp79/DashBoard57.csv?dl=0
It's in a 67 Camaro, GM crate 350/290hp w/Promaxx heads (~9:1 compression), cam is relatively mild (.470 lift Comp Cam Magnum), ignition is all brand new MSD pro billet/MSD Superconductor wires using timing control.
Thanks in advance! Matt
Hi Matt,
probably won’t make you feel any better, I never did figure that out either.
I changed to the recommended AC Delco replacement temp sensor. It did raise my temp readings about 15 degrees above what it was. So my avg temp is over 170 during normal driving. However, AFR Learn is still maxing out @ -35.2.
Sorry, no help yet...
I also posted this on a Facebook group and someone suggested an exhaust leak and another suggested going to cam 3 as that has less fuel at idle. For me, the cruise/highway cleans up really nice, but idle is maxed out negative. I'll give it a try when I'm home and post back any progress.
Yes, do let me know. My car is currently in winter storage but I’m picking it up Sunday.
I would like to be able to sort that out.
Just reading this post. I have had a nagging idle fluctuation forever. I have tried all I can think of, all it has been suggested, and although it has improved slightly it is still there. When I started reading this post I went to check my logs and realized that the AFR learn is evidently stuck at -35.2% in idle. I guess I never paid attention to this column probably because I didn't know what it meant. Has anyone found a solution? In other post I read people changing to cam 3 or 1 with no changes. I am right now at cam 2 with 11-12 Hg vacuum. Besides the issue at idle, it runs great.