I have an 87 IROC 5L TPI engine that just failed emmisions for the second time. The NO is sky high (got worse when I advanced the timing to 6BTC from 2BTC and added dry gas) and my next course of action is too look at the EGR (replace or just clean). I will see if I am getting any vacuum at the same time (the intake manifold is leaking radiator fluid, wonder if this has some effect). Also, I guess looking at the airpump is not a bad idea. Anyways, am wondering if I have to take anything off to get at the EGR as I know it is buried. I would fix it as same time as intake gaskets but I only have another week or so to get the emmisions problem fixed.
Thanks for any input.

 

You will have to Pull all that stuff off To get to it.

its sorta buried in there.

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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

You will definitely have to remove the plenum, like '62 said. I'd suspect that you are correct in pinpointing the EGR system for your problems. It is the most significant force in lowering NOx emissions. The purpose of the AIR system is basically to remove unburned hydrocarbons from your exhaust by burning them with fresh oxygen, so save your time for the EGR system. Also make sure you aren't running rich...that increases NOx production as well.