Hi guys,

I can't seem to get my 92 z28 to pass Cali smog for high Nox. I pulled the plenum, pulled off the EGR and checked it. It holds vacuum and opens and closes when vacuum is applied. I believe it's actually new. There was no clogging in manifold hole when I removed the EGR. When I reassembled the intake and started the car, I manually applied vacuum to the EGR and the car does not stumble or act like it wants to stall. Is it looking like I pretty much have to pull the entire intake off and check for clogged exhaust ports in the head or intake? Any way to check without removing the intake?

Thanks for help


Rick

 

A bore scope would allow you to see the passages. I would get out a stretch of speedo cable and pretend that I was a plumber- stick it in one of the ports and move it around to see if you can dislodge the blockage.

 

Thanks, I'll try. What's funny is that there is no indication of buildup under the EGR when removing it. I wonder if it's possible that when I R&R'd the intake I put the wrong type of intake gasket on there and actually blocked of the exhaust port?