HumpinSS

iTrader: (1)

Power Enrichment and Open loop Fuel air

I know when I am WOT I am in open loop so if i wanted to lean out my mixture for 100 kpa and rpms greater than 5K which table would i use

Pe vs Rpm or Open Loop F/a

TIA

jimmyblue

iTrader: (11)

I have been told that the way it works, is the PCM
picks the richest alternative. You have PE vs RPM,
and you have open loop AFR vs MAP & ECT. If PE
gives you fatter, you get the PE number. If Open
Loop is fatter, you get that. The PE only applies
above the MAP threshold and runs w/ RPM while
Open Loop is MAP-parametric. So you really have
two degrees of freedom (including freedom to
screw up) here. I think to do it right you'd want
to use both, but need something like an Excel
second-order map of it to make sense - like get
both tables in there, and then surface-plot the
max(PE(RPM),OL(MAP)) function to see what
you will get.

Why PE is not a function of MAP and RPM, I
have wondered for a while. I guess at WOT
you would assume MAP=100kPa. But PE applies
down pretty low, like MAP>=15kPa in some
tunes. Open loop I believe is any time the
fuel/air multiplier <>1.00.

Anyway, to lean you out you would look at
which of them is in control. If you knocked
PE way down but OL was still a bit chubby,
you might not get as much effect as expected
from the PE change.

HumpinSS

iTrader: (1)

That explains why I decreased my PE vs rpm values and seen no change in my O2's at WOT. Thanks