[83gs1100g]

I have a vacuum gage on the vacuum line to the egr so I know when it turns on and it never does? I got a new cvc so I know thats good. I tested the egr solenoid and checks good. I swapped ecu no help. I ohm the orange/blue strip wire from egr solenoid to ecu and was good. My question is what sensor or sensors does ecu need to engage the egr? Maybe I have a bad sensor to the ecu so egr can't engage? Any thoughts???