Condition: EGR does not actuate.

I've replaced the EGR, tested the circtuit and EGR function and come to the conclusion that the PCM is not sending signal to the EGR to operate.

What could cause the PCM to NOT send the signal to actuate the EGR when the engine is fully warm and RPMs above 1500?

Manual says coolant temp sensor, MAF, and TPS influence EGR. I've tested power/ground/function/circuit to PCM for those sensors. All good but I do not know how to test calibration on the MAF or ECM.

1997 Camaro 3.8L 5 spd, runs fine, no codes, and 165k original miles.

 

Are you testing with the engine under load or just revving it up in idle? The engine needs to be driving the car at normal road speed in order to operate, that is why the PCM needs an input from trhe MAF and the TPS; RPM at idle is not enough. Find someone with a bidirectional scanner and have it order the PCM to operate the EGR. Then you will know for sure if there is a problem.

 

How would having a load on the engine influence the PCM to send a signal to the EGR? I warm up the engine and rev/hold RPMs up to 3k.

Do bidirectional scanners (or laptop equivalent software) exist within the do-it-yourselfer price range?

 

An engine under load at 3000 RPM will flow more air (MAF) and have a larger throttle opening (TPS) than the same engine just holding 3000 RPM while in neutral. I really think you are shooting a balloon.