Just wondering if anyone can help out? Im using the 7747ecm with $42xdf and there is a constant that has a title of Cold PE afr?? It has a factory setting of 2.5. Does anyone know if this richens or leans out the afr when in closed loop or when under a certian temp? And if it does it by that amount of if its a Multiple?? THanks for any help!

 

If that parameter is the one at $2D1, then it is subtracted off of the looked up PE AFR value (from the table). This is done if the coolant temperature is less then the parameter at $2CF, and the RPM is less then the parameter at $2D0.

Note that the PE AFR is also checked against the open loop AFR. And the richer of the two is selected for use while in PE mode.

RBob.

 

So then it would in turn make the cold afr pe richer then? If its subtracted? Or would that make it leaner? Thanks again Rbob

 

Richer. A lower AFR is richer.

RBob.

 

Thanks again!! So i was right to zero out that adder for cold pe when it would go rich. It would go rich when cold with a setting of 2.5afr adder. So i zeroed it out and it seems to be much better.