went to smog the 190 today, and failed smog due to high nox emissions and high hc. took the car home and examined the EGR valve and i found the rubber vacuum hose to be completely ripped up. second, i applied vacuum directly on the EGR valve and the diaphragm did not hold the vacuum at all.

so it looks like I will need to replace the EGR valve itself and the vacuum lines that go with it. my question is, how do I ensure that the EGR is working when supposed to? in order words, when does the EGR valve get vacuum to open up? at partial throttle? full throttle? certain rpms?

thanks in advanced.