90 Celica, high NOx / HC, new cat, working EGR, no cloggage

[bafoon]

1990 Celica
4AFE = (4cyl, 1.6L)
224k miles (still breakin 'er in!)

I have a 2 yr old catalytic converter that I bought when I failed for NOx and HC 2 years ago. That seemed to have helped me pass, but apparently didn't solve the real problem. I failed again this year. (NOx was like 3000, norm is 1500) and I think HCs were (190 if norm is 120). The HC numbers are def wrong, but the idea is that my reading was not quite double the norm while it was slightly over double for NOx.

Vacuum Modulator and EGR:
-cleaned, tested, "working" <-- I'll explain

here is the order of EGR system components...
Vacuum Modulator -> EGR -> Something small with a plug/wire (VSV?) that is located behind the block, attached to a rack that "hangs" from the intake manifold


Dealership said EGR is inop... buying a new one didn't seem to change much - applying vacuum to the EGR didn't cause idle to stumble. I took off the throttle body and realized that the passage from EGR opening to top of intake manifold was clogged (no carb cleaner came out of the EGR opening when sprayed in at the top of the passage). So I cleaned it.

Still, applying vacuum with a hand pump to the EGR did not cause the idle to stumble. Then, I decided to test the EGR (while connected) as I would have if it wasn't connected (by plugging one of the top ports while applying vacuum to the other). This did cause the vehicle to stumble at idle.
Additionally, I tested it and the vacuum pressure coming from the vacuum modulator to the top of the EGR seemed to be sufficient to open the EGR valve when revving a little. However, when using a mirror to observe the valve, I do not see it open when revving unless I, again, plug the port going to that last component of the EGR system. Then, I could see it opening (a little bit) when revving.

My thinking is that maybe that last component (is there a VSV on a 1990 4AFE?) is perhaps "stuck open" and not allowing vacuum pressure to build to open the EGR. When I look for a VSV to buy, I cannot find one. For this reason I am not sure if this is indeed a VSV - though it seems to be in a location to do what a VSV does (could it have another name?)

Thanks,
T


Also - not sure if this is related...

I'm looking into my engine compartment at my intake manifold.. on the left SIDE of the manifold, near the top, there is another small part with a wire/plug attached. I looked at some diagrams and it seems that it might be an ACV (Air Control Valve) - though this is another one of those parts that I cannot find anywhere. Does this have another name? Or does anybody have any idea what it does? I ask because it ticks a lot once warmed up and idle is reduced to 700. By "ticks a lot," I mean pretty much all of the time. I actually thought it was a slight valve tap until I used the screwdriver-to-ear technique to pinpoint where the sound is coming from.

[bafoon]

UPDATE

It was the VSV.. I never found one to buy, but instead I plugged up the vacuum hose going from the EGR to the VSV. This caused EGR to always function. Made the car drive like crap with lights or AC on, but it helped me to pass the NOx emissions. I'll have to find a used VSV somewhere.