Hotwlz

Hi all I just recently acquired a 1981 sr5 long bed with a 22R it runs great after all the following:
Cap
Rotor
Plugs
Oil change
Fuel filter
Accelerator pump
PCV Valve
Thermostat
It has failed smog due to hi hc and co2 at idle (445 ppm and 7.15 respectively)
I have a few questions I have read in the FSM that the idle mixture screw should be turned all the way in and backed out depending on the year, between 2.5 and 4.5 turns does this screw the farther backed out lean the mixture or richen it up and what could be causing the co reading?By the way this thing runs like a champ while driving.
Then today on the way to re smog it, it started to die at idle, and after finding that the results were a little lower it starts to spit and sputter until you feed it some fuel then it will idle great for 5 to 10 min then will sputter and die and doesn't restart easily. The level in the bowl is a little high but remains at the same level. Could the fuel filter be clogged already? I am at my wit's end and any help would be great.

slow-mo

The farther out you unscrew it, the richer the idle fuel circuit gets.

It sounds like you may have already done adjustments to the screw to change the carb's idle behavior.







No.

A clogged fuel filter would cause fuel starvation to the fuel bowl, which you say has a high level of fuel.

You should readjust the float level of the carburetor, as a high fuel level will cause a rich mixture of the carburetor. You wont need to remove the whole carburetor to adjust the float level. That can be done by only removing the top Air Horn portion of the carb. Yes, I know, easier said than done, but it can be done.


This link has some good reading about emissions and how they relate to each other and what causes what.

http://www.autoshop101.com/forms/h56.pdf

rokblok

iTrader: (1)

I thought the screw was tapped into an air passage that drew in filtered air causing it to lean out the mixture...?

Hotwlz

Thanks for the advice took the top off the carb swapped the float and the needle valve got adjusted fuel right in the middle of the sight glass only stays like that for a few mins then all the way to the top and then sputter and die, could the new manual fuel pump have to much pressure and is stronger than the float so it just fills and fills. This has only been doing this since the new pump. Any help I really appreciate.

slow-mo

If your taking about the Idle Mixture Screw, then no. Here is Toyota's picture of the idle fuel circuit.

What is being metered is fuel, albeit mixed with air from the Air Bleed intake ports.

slow-mo

In the factory service manual (FSM) you'll find the section on how the fuel pump works and how to test it.

There is a PDF version of the FSM somewhere here on Yotatech.