So 1986 22re 4runner failed smog. Guy said it was running rich, the test shows high CO

Attached pics with readings.. any tips? I had retarded the timing a bit by hand and tried to raise the idle as much as possible before this test.

Should I drill out the AFM screw and lean the mixture a bit? Put alcohol in the tank?

 

How old are the plugs?
Do you know when the oxygen sensor was replaced?

Iirc high carbon monoxide is related to combustion temperature. And you have a pretty low HC reading so it's burning just not hot enough.

​​would strongly recommend not to mess with your air bypass in the AFM, these are calibrated at the manufacturer by greybeards bases on the spring in place and the circuit board they will all be slightly different to compensate for this. The much safer modifications are on the spring gear under the cover, since you can go right back to the factory setting, but even this can go bad (like really really bad) if you aren't methodical about marking the position and "boing" spring loose. (And of course there are plenty of stories of people trying to disassemble it thru the plug hole!)

 

thanks for the help!

Sparks are new.

Sensor: no idea, been in my hands for a few months. The last guy sold it to me with broken chain guides and leaking front seal so I addressed that along with new oil pump and water pump. new cv axles and other goodies. Also adjusted valves to hot spec (first time doing the procedure, I think I did it pretty good / close to spec)

I'm gonna guess that he had it passing smog and probably did some work before the engine started leak and chain noise, I say that because the charcoal canister looks new-ish.. or at least not as old as other parts. The o2 sensor is mud dirty but aside from that looks not too old? really can't tell looking at it and have to idea

I actually thought the opposite, but I may take your advice. ALSO NOTE i just realized the sensor cover has been removed before, and siliconed back together, sorta badly. A few drops of mud in there from my last mudding adventures. Very little, just a drop, but still not sealed. Makes me wonder what they did to it.. maybe richened it? Maybe I should move it a few teeth? I guess I'll take a look at some youtube videos for the procedure, unless there's a good write up about it you could recommend?

 

Look for the write up Jeff Mosk did about tuning the 22ret vafm, it will give you specifics. And of course it can't be said to many times clearly mark the starting position.

If your o2 sensor is dirty on the outside it will not function properly, they work by comparing the exhaust to the atmosphere thru a small capillary port. Iirc mine was about 30-40 from denso.