Greetings. I am trying to get an '88 IROC, 5.7, TPI to pass California smog. Yes, I have a better chance of winning the lottery! However, I passed everything except the NOx. Looking at the EGR valve as the culprit. Question: On the EGR valve solenoid, there is a two wire connect, a dual vacuum port, and then a 5th connect (looks like some sort of vacuum port?). Does anybody know what connects to this?

Hate to keep throwing my money to the smog station. Thanks!

JB

 

The third is an atmospheric vent, to allow the EGR valve to return to the closed position and vent the vacuum when the solenoid shuts off. The original installation setup should have had a small cube of foam acting as a "filter" on the third (vent) port.

 

Thanks a bunch. Do you happen to know what connects to that port? Or does this cube of foam terminate the port?

 

That's it. The cube caps it off.