egr and smog nox

i failed cali test on the nox by 700 ppm (double) the limit.(egr disabled)
i am 80% sure its the egr . but can the egr alone cause such a high fail on nox ?? 90 iroc 5.7 ....7k miles on cats..new o2,wires plugs ect ect..i'm running 128 to as low as 108 on short term bar /with 22 lb injectors, headers, tpi runners, ported T.body...i was going to bump up the injector pulsewidth to compensate but i was afraid to go richer because the HC passed but it was close.. what do you guys think?? thanks for any/all help

A.b.s.o.l.u.t.e.l.y.

I have a carbed '86 with the 305. I went through VA emissions not knowing I had an intake with no EGR. My NOx was horrible!!!! Installing just that with no extra work on emissions cut it by 50% (though it was still illegal at that point).

If all you failed was NOx, get the EGR working. FYI that I also saw no performance hit when the EGR was installed. It still runs great.

I failed Nox in California and it was the CAT. Actually some one must have jammed a pipe through it put back on because there was nothing inside of it.

Well i know where to start..do you guys think i should go a little richer to cool the cylinders as well as the egr ?

If you go richer you may fail HC's.

I'd simply make sure that your emissions gear is working, at least for the test, and only mess with rich/lean after that. All the gear has to work together to make your emissions clean: EDR, smog pump, EEC, and cat. Any one of those not working will blow your chances of passing, in my experience.

My saga was that all of that gear was disabled or removed. Even when it was all attached, I was still failing and it turned out to be a fouled plug. Replaced that and she was clean.

So check your gear first and only mess with other motor parts afterwards.