I am wondering what the emissions computer controls on a carbureted 22R. I see some sensors, but I cannot seem to figure out what it controls. Does anyone know what it does? Does it store codes that can be retrieved?

 

It is a very rudimenary form of emissions control found only on California spec trucks. There should be a couple wires going to the carb (on top of the bowl) and an O2 sensor and maybe a temp sensor depending on year. The wires going to the carb control a solenoid-operated metering rod which richens/leans out the mixture as told to do so by the ECU and O2 sensor. My experiences with this system have told me it is somewhat trouble-prone and the metering rod tends to be stuck in one position, usually somewhere in the middle of the range (where it spends most of its time), and doesn't really have any detrimental effects to performance and/or emissions. I'm not positive, but I don't believe this system stores any codes as there really aren't any to store, it just doesn't monitor enough equipment.

 

Thanks for the reply. I have a lot of carbon build up and I was thinking that maybe my mixture is rich, so I will check that.

 

i though all trucks from the mid 70s on to the end of the carbureted era had a little "computer" box in them. my friend's 76 did, my '79 does(albeit unplugged ), and my '84 2wd had one. all were federal emissions trucks, and the box said "emissions" computer on them

from what i've heard, they do a few basic functions, and also control the fuel cut solenoid which helps prevent raw fuel washing down the cylinder walls and improves engine braking

 

I'm pretty sure it moniters cooling fans and the heater and all the little electrical components also.

 

not on a carbed truck, i don't even think EFI trucks had any kind of fan monitor

 

My '84 had no computer whatsoever. No O2 sensor, no other sensors (other than gage and idiot light), no wiring other that required for engine operation, etc.

 

i have an 85 4x2 22r CA based truck... i have a "emissions computer" under the right kick panel

 

Canadian trucks had one of these also :-)