My truck (84 toyota xtra cab) passed safety just fine, My trouble is the emissions. It was over on the CO.

The max for 15 mph is 2.63 and I came in @ 3.98
The max for 25 mph is 2.72 and I came in @ 3.86

What causes high CO levels, and what can I do to help it come up to spec?

Some ideas I had are:
Spark plugs
adjust carb?

Any ideas would be greatly appreciated.

 

welcome to yototech........you have a catalytic converter also know around here as cat ?

 

High CO = engine running too rich.
http://www.barneymc.com/toy_root/techneek/smog_tip.htm

 

Thanks guys I'll start by adjusting the carb then. Yes I do have a cat. Is it posible that the cat is bad, causing the failure? I just had a cat back 2 1/4 exhaust installed they said that it wasn't too bad. Any other ways to get the mix lean should I adjust the timing a little advance?

You guys are awesome and I appreciate all the knowledge on the board i have been lurkin for a while and I am really impressed.

 

Do 22r's have an O2 sensor? And better replace the Air cleaner, plugs, dist cap, and rotor for general maintenance if you haven't in awhile.

 

Make sure that all your vacuum lines are in the correct place and that your timing is correct. Also check the vacuum advance mechanism. Both of the diaphrams should hold vacuum. Also make sure that your EGR is working.

 

With all my older trucks I will always replace plugs, clean the air filter, and give it a quick tuneup before emissions tests it always works wonders!

 

Thank you so much for the help and response, this forum is great!

I swapped the plugs out and leaned out the carb. And when I went in the tossed it on the dyno to see where it would read, I was acctually higher in CO than before. But I was really suprised with the customer service of the shop. They grabbed another guy to tune the carb and adjust the timing while the other guy was running it on the dyno until they got it to a level where they were sure it would pass. It did and now I am good to go!

 

Rule of thumb, HC is a mechanical problem while CO is a fuel problem. In your case, rich. I suspect its a dead oxygen sensor.

 

84 22R's dont have O2 sensors.

 

Want to put a wager on that?

 

that is news to me
22r is the carb version and has no need for a O2 sensor (unless some weird california version)

not doubting the source but have never seen it

 

California smog carbureted 22Rs have an oxygen sensor to run a feedback system controlled by a computer, which is more precise than the smog pump used on federal smog vehicles.

 

Many carb'd 22R's used an oxygen sensor to operate the air injection/suction system. Also, there is a Toyota truck in 84 that was EFI and came with an 02 sensor also. My boss owns one, a 1984 2WD extra cab SR5, its EFI!

 

My 85 Toyota truck has a carburetor and also has an oxygen sensor.

 

I guess I should of asked the origninal poster if he does have carb or EFI. I know EFI on an 84 is rare. I think it was 2WD's only. Anyway, excessive Co might be as simple as the air suction system inop. On the 84's, the air suction system made a growl, especially wi th the air cleaner lid off. This is the diverter vavle directing air into the air cleaner. It will do this on decel or idle. But at cruise, it shoudl direct this air into the exhaust. SNap the throttle a few times, you shoulds hear the air blow into the exhaust (quieter) and then switch back to the air cleaner on decel (noisier) and if the system has been inop for sometime, the reed valve on the air pipe may be corroded shut.