Hey Guys,

I am trying to find out how the PFC works as far as the controling of the injectors. I got my car tuned for 10lbs and 15lbs during the end of summer. Since it's winter I am staying away from the 15lbs setting (worried about running lean), but I am trying to figure out if it is safe for me to run at WOT if I am on the highway and it is below freezing outside.

Does the tune on the PFC restict the injectors to only run at the settings that it is tuned for, or does the PFC set up so it automatically adds fuel to keep the car at the same a/f ratio as what it was tuned to be at.

For example, let's say I was tuned for an 11 a/f while it was 78 degrees farenheight outside, then when it's below 30F outside, does the PFC automatically raise the injector duty cycle to keep the same 11 a/f ratio? Basically, if I was tuned to an a/f of 11, then am I still good for going WOT as long as the injector duty cycle is under 95%? Or will an 11 a/f ratio in the summer become more like a 13 a/f ratio in the winter even though the injector duty cycle is only at like 80-85%?

Sorry about the long post, but trying to figure out how the tuning for the PFC works.

Thanks guys.

 

There is a Datalogit Air Temp vs Injector table which is suppose to keep the AFRs constant.

It worked OK with a stock engine because Mazda had it running so rich in summer that it actually leaned out for better AFRs in winter. Thus it is not very safe for winter with a leaner running engine.

The Air Temp Sensor is also located under the UIM which heats soaks more which can give false higher air temps than what is coming out of the IC.

Best to move the AIT sensor to the throttle body elbow where Mazda had it on the Cosmo twin turbo 13B.

Best to linearlize the table and tune the engine in winter first for save timing and fuel. Thus in summer the timing will be even safer.

Such things are listed in my notes package.