EFIDynoTuning Forum

anytime I go into decel in closed loop the AFR coming out is rich, the longer the decel the richer the AFR. Is there anything I can adjust to try to help out with this?

On the mechanical side are you possibly pulling in oil vapors from leaking valve seals, stuck open PCV valve, or fuel vapors from a stuck open EVAP purge solenoid or other extraneous fuel source? This would be most prevalent under high vacuum.

My other guess on the tuning side would be if the computer is learning closed loop fuel adjustments under decel when the AFRs would be leanest, but don't listen to me I still have a ton to learn. Is your pedal position status going into dashpot on decel? I would imagine but can't say for sure this should tell the ECU not to learn fueling during decel. Perhaps Decipha or anyone with more knowledge than myself can say if I went off on the wrong trail.

I dont think its mechanical because I just noticed while still in OL the other day it didnt do it. I have a feeling its the ECU trying to compensate for the lambse ramping lean while in decel but not 100% sure which is why I posted, I am still always learning myself.

just to update this I adjusted hego delay fn1351 out to 20 in all cells and it has helped quite a bit, the base tune I started with had this table populated with lower numbers. I went the wrong way at first and the lambses were switching super fast lol and once I realized and went to all 20's it settled them down nicely.