tuning afr

s300 and SManager software questions & answers
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Posts: 1
Joined: Mon Oct 15, 2018 3:16 am

tuning afr

Post by luciarakan »

1. ok i street tune my afr to 13.1 in 4th gear before i went to the car cruise last satuday night the next day i look at my onboard data logging and it show my 2nd gear afr went lean to 13.4-13.6 and 3rd gear went to 13.2-13.4 but it looks okey and my 4th gear was 13-13.2 afr... why is the afr goes lean?

2. is there anyway how u can tell the car is breathing good by just looking at the map sensor reading at datalogging?

pls dont tell me to tune my car on dyno becuase its expensive it can go 1000+ bucks....


Posts: 2
Joined: Tue Jan 08, 2019 3:33 pm

Re: tuning afr

Post by Turbocivic6776 »

There are numerous reasons that can be the cause of this. Was their a air temp difference? coolant temp difference? If the fuel compensation tables are not properly configured then you may want to adjust them to make sure the AFR stays where you want it as temperatures change. If you tuned during the day and never touched the comp. tables and then drove at night with a 20 degree swing in ambient air temp. then you must adjust your fuel comp. tables to give it more or less fuel to keep the same AFR. hopefully this is helpful to you.

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