jpandes

I know that the PFC compensates for a cooler temps by adding more fuel or retarding timing when the car isn't warmed up or if the intake air is cooler.

Do you guys fiddle with the PFC temp correction settings to make the car run 12.5-13.5 AFR's even when the car is still warming up?

Or is the car supposed to run stupid rich(10.x) when the car is cold and not under boost(vacuum)???

Xcessive

Yes

jeff48

As you point out, the compensation maps are factory engineered to provide very safe and conservative fuel/timing combinations at different temps. The maps are based on a zero point of 40 degrees C ambient (the temp determined to be the optimum temp for intake air in an internal combustion gasoline engine).

The only time I would change the maps is if I were to completely retune the car at an ambient temp more than 10 degrees higher or lower than 40 C. In those cases you will need to change to "0" point and reflect that change in the remaining compensation cells.

For example: If you are retuning ALL your maps and basing the changes on dyno testing AND your intake air temps are consistently 50 degrees C. You may want to reset your compensation maps to reflect 0 (no compensation) at 50 degrees. You would then change amount of compensation applied at 40 degrees (add a % of fuel and subtract a % of advance).

There was a real good discussion of the IAT compensation tables on this thread some time ago.

The short answer to your question is to not mess with the compensation tables unless and until you COMPLETELY re-tune the car at an ambient IAT of 10 degrees more or less than 40 degrees C.

cewrx7r1

iTrader: (2)

Plus the some of these only can be changed with the datalogit. The AIR TEMP vs INJ is not to be trusted in my opinion because Mazda set it for their tuning of a stock engine. A highly modified engine will have different requirements. As someone mentioned a long time ago that since Mazda runs so rich, they actually start removing fuel as temps go down. If you have all the good mods, then you want liner AFRs for normal driving temp ranges.

I also moved my air temp sensor to a place where it does not heat soak. Since it runs about 10 degrees cooler, I had to change my AIR TEMP vs IGN table.

I tuned my car last spring when it was cool. When it heated up in summer, my AFRs went .2 to .3 leaner.
That is when I moved my temp sensor and recalculated my AIR TEMP vs INJ values.

jpandes

Thanks for the advice guys. I appreciate it.