When performing an EGR system test on a vacuum operated EGR valve, how much should intake manifold vacuum decrease when the EGR valve is opened at fast idle?
A) 1-2 in. Hg.
B) 6-8 in. Hg.
C) 6-8 PSI
D) 14.7 PSI

Question

Quizplus · Accepted Answer

When performing an EGR system test on a vacuum operated EGR valve, intake manifold vacuum should decrease by 6-8 in. Hg when the EGR valve is opened at fast idle. This indicates that the EGR system is functioning properly and that exhaust gases are being introduced into the combustion chamber.

When Performing an EGR System Test on a Vacuum Operated