Got a 91 4runner with the 22RE. Damn thing is now known to the state as a gross polluter due to high NOX. I put vacuum to the EGR and the motor stalled so that seems to be good. Anyone else had this problem? Need help fast.Forgot to mention that I have backed the timing down to factory specs.
NOX CAN be caused by high combustion temps. It can be a tough one to get around as well. What I have seen done in the past, to pass an emissions test (if you just have the sniffer test, not a visual inspection, is to take a wet (but breathable) fabric, and put it right behind your air filter in the intake, for God sakes make sure its stuck, and the much moister air can lower your NOX long enough for the test. I do not guarantee results and I am a LONG way from recommending this to anyone. I've just seen it done, by some of the "bubba trucks" in the area, and thought I would mention it. Otherwise.... start checking sensors and the EGR system very thoroughly.
-Chris
2004 DoubleCab Tacoma PreRunner: 3.4 V6-Auto, DD/Tow Rig
1997 Lexus LX450: 4.5 I6-Auto, DD
1984 4Runner: 22R-5 speed, 14 inch bob, 5.29's, lincoln locked rear, lockright front, Armored and Caged by Mossyrocks Fabrication, total disregard for body damage.
1997 4Runner: GONE
1996 FZJ80 Land Cruiser: GONE
Like Chris said high NOx is generally from high combustion temps: inoperative EGR, lean condition (vacuum leak, low fuel pressure) or cat converter. Do you still have the original catalytic converter on the truck and how many miles are on it. Cats are generally good for 100k, but I've seen them stay effective to 200k on a well maintained engine.
You could also have carbon build-up in the combustion chamber raising your effective compression ratio and comb. temp - try feeding some water at idle from a cup thorough one of the vacuum lines, as long as you're not dumping the water in you'll be fine (it steam cleans the combustion chamber, very effective). After every 1-2 cups goose the throttle a bit clear it out
Keith '88 4runner SR5 Garage Thread
All lines appear to be in good condition. Not sure about carbon build due to engine be a fresh overhaul but I guess as much black crud that has built up on a new exhaust might be a sign of that. Cat was replaced about 3000 miles ago. Time to take it and get a pre-smog since the timing has been dropped about 11 degrees. I'll report back when it doesn't pass again.
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