It was time for my '86 to get smog tested (22re with recent rebuild, bored .020 over, NWOR cam, LC header). HC and CO both passed but failed NoX 7.5 grams/mile. <img src="/forums/images/graemlins/frown.gif" alt="" /> So, a lean condition is what I thought the problem was due to the modifications and recent engine bore. Checked all the EGR parts and they were functioning as they should. No engine codes were being thrown. So, I popped the top of the AFM and adjusted the gear 4 teeth CCW. Reset the computer and drove it for a day before heading back to the retest. Went and got the test done yesterday and whoo hoo! The NoX passed beautifully 2.83 grams/mile against the max applicable standard of 4.5. Life is good for another two years <img src="/forums/images/graemlins/kewl.gif" alt="" />

I also found with the LC header there is an issue with the factory exhaust manifold gasket and the header EGR passages. The gasket has a big hole for the exhaust and a small hole for the EGR port. The web of gasket between those two holes gets sooted up and blocks the gas flow. Also, I found the weld bead where the big tube is welded to the flange partially blocks that small passages as well. So I used a Dremel to grind down the weld beads a little then cut out the web of gasket material between the two holes to make a single large hole and that increased the EGR flow enough to drop my NOx readings enough to pass the CA smog test.

My EGR ports were working well due to the fact that when I was checking out the EGR system, whenever I activated the EGR valve while the engine was running, it would just about kill the engine. So I knew plenty of exhaust gases were being recycled. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Mine would do that too, it does not take much exhaust gas to kill the engine at idle. What I found was that on the Calif. dyno test, especially at 25MPH, the engine is really ripping along, I think 2800-3000 RPM and with the little 22REs, pretty open throttle too. That means a lot of air of getting sucked into the engine and it is hard to get enough exhaust gas through that EGR valve to have much effect. I think the early 22REs, had only a minimal EGR system as they did not have to pass NOx tests back in those days.