Sirs,
I have been logging for a few weeks and cannot seem to nail down a consistent Open Loop SD tune. I have noticed that the same tune reacts differently at different times.

Example.
This morning IAT averaged 55 F (52-66), AFR averaged 14.68 (12.50-16.81).
This evening IAT averaged 100 (91-111), AFR averaged 15.08 (12.64-16.82).
Both runs were ~30-45 minutes under mixed daily driving, no WOT, same tune.

1. How much does temperature effect AFR?
2. Are these differenced temp related or something else?
3. If temp related, what map should I change (using EFILive) to compensate?

thanks!

 

theoreticly, what you are seeing is incorrect. warmer temps would make the car richer and cooler, more dense air, would make the car run lean. i would check out some of the spark tables and see if there are any corrections going on. what about coolant temps? that can play a role as well. cooler air keeps coolant colders and that would effect some of the timing values as well

 

and you did you average that? i am guessing you are in closed loop? it would be hard to average and get consistent numbers really

 

What effect does the IAT modifier table have in open loop?

 

it adds to the f/a multiplier to increse start up enrichment IIRC.