When to go into Closed-Loop?

[peter paul fenske]

Hi Guys 

To guote a Gm Advanced Fuel Injection training manuel
you enter closed loop on the following conditions:

Ctc above 159 degrees

O2 voltage swings more than 200 mV from the setpoint of 450 mV. The
02 sensor is biased to 450 mV through a 10M resistor.

More than 70 seconds have elapsed in the engine run timer.

Also there is one form of open loop the power enrich mode which
is entered during hot closed loop when tps exceeds a certain
percentage at different rpm breakpoints. The F/A is then run off
PE open loop enrichment.

Have fun: peter

Ps manuel was available from delco electronics. I don't know
if you can still get it.