Junkers88

Doing some work on the 89 (22re) and notice that when it's cold it idles pretty fast. I had to start the truck (86 22re) and idle it up by hand to about the same speed, by ear, as the 4runner to figure out how fast it was going since the runner doesn't have a tach yet. It seems to be between 1500 and 1800 rpms. The truck idles at 1200 no matter how cold it is outside when I start it. Once the 4runner is warmed up it idles just fine and as per the emissions test I did a while back it idles at 850-900 rpms. I know it should idle at 750 but without the tach I can't make that fine of an adjustment and don't want to idle it down too low. My SR5 gauge cluster should be here in about a week so I'll be able to swap that in and fine tune the idle. I'll also check the timing at that time.

From what I've read the 22re should idle warm at 750 and cold at 1500. Could the little bit of higher idle at warm temps cause the higher idle cold? What I mean is does the ECU know that the warm idle is higher so it makes the cold idle higher also?

If not then what may be the cause of the fast idle when cold?

Thank you.

abecedarian

Idle speed is controlled by the air bypass screw and the auxilliary air valve (which is open when cold and closes as the engine warms up) and a/c idle-up valve (raises engine speed when a/c on). The ecu has no significant control over idle speed.
I wouldn't worry much about the cold idle speed as long as the engine does idle properly when warm.