Does anybody know what is supposed to happen before the egr system actuates in a automattic '94 SR? The basic's I know, in gear, warmed up, and under moderate load. What I want to know is what sensor outputs are needed.

Maybe we could start with the egr solenoid voltage. The voltage at my egr solenoid varies from 0 at idle to battery voltage at around 2500 rpm.

And yes I'm asking these questions because of high nox. Here's the numbers:

15 mph co2(15.2) o2(0.1) hc(27) co(0.20) no(1565)
25 mph co2(15.2) o2(0.0) hc(16) co(0.18) no(1598)