I just bought a 1984 22r 4Runner, the guy I bought it from did not live in a area where testing to get tags is done. So I learned a few things getting the rig to pass DEQ. I thought others may find it interesting or it may help them at some point in time.

Bought the truck the cat was hollowed, so knew it would not pass, but I wanted to see what the numbers would be.

First trip through, it blew 858, limit here 220. This is low idle HC all other reading passed. So I bought a cat and had it installed, bck to DEQ. This time it blew a 247, dam missed it by 27. Ok, it still idled ruff, I could not get rid of it. So, new plugs/checked the gap before install, new wires, new cap and rotor. Still could not get rid of the ruff idle, I turned the dist to full advance and full retard slowly with all new parts. Still ruff idle almost fart sounds in the ruffness. So more reading books and sites.

Figured out the EGR valve on my rig is bad, buy a new one $186.00, I install it. Dam idles nice, so back to DEQ. The thing blew a 10. yes just ten.

So what I learned is a bad cat makes a big differance, over 400 HC's. A bad EGR will bring it up 200 or so HC. Both fixed you can pass and get tags and put the rig in your name. I kind of always wondered if the stuff really does anything. But to go from 858 HC's to 10, they must work.

The plugs and wires really were not that bad, they made have played a part in it, but it could not have been too much.

 

EGR will really help with emissions -- it lowers the temperature of the combustion chambers when and helps prevent creation of NO gases. a nice benefit of it is that when it's working properly, you'll burn less fuel at cruising speed.