Start-up RPMS when cold on SC

[Vereeken]

Out of three AARs I made one new one that would suit me more.
By using different bimetals and opening shapes I want to get to an automated cold throttle that does what it needs to do without excessive high rpms.

Can you tell me what cold start rpms you get on a 79-83 sc and at what outside temps, and how long it takes for the rpms to come down.

I have the feeling that 1800 rpms is needed at start-up but would like to come down quicker then a standard xxx-201 AAR.

Do SC's that work correct at start all see this 1800 RPM? If so how long?
Will I see a difference between non 02 and 02 cars?

Michel

[SkiVT]

I have an 83 ROW with same AAR as your OEM. I have been knocking the adjustment "pin" around for a year or two to get to a happy medium of adequate initial cold running and dropping off the "high RPM". My opinion is there is no "normal" at the age of these components so this may not be of much help but. My rpm's go roughly like this:
Summer: first 30 seconds 1,100, then jumps to 1,600 for about 2 min, then drops to 1,200 and then down to 900 over the next several minutes.

Colder Weather: the time at 1,600 extends by a couple minutes.

My normal driving has me pulling away from the driveway within that first 2 min so the time at higher rpm isn't really that noticeable. I have reduced the 1,600 to around 1,200 by adjusting the pin but it makes those initial 2 min a more grumpy idle.

[Vereeken]

SKIVT, I have that same experience. I do not understand where that jump from 1100 to 1600 comes from.
I also have opened my AAR and replaced the bi metal with a 20 OHM bi metal vs the original 32 OHM , it gets me quicker from high to 1200 rpm
I have the feeling I want to start at 1400 but that is like aiming for the impossible with the adjustment pin....
I understand why solid state electronics became such a big thing in the 90's ;o)

[SkiVT]

Same confusion here. My belief is the mixture is so pig rich before the thermo valve opens that even the AAR air isnt quite enough to raise the idle. Therefore, the jump is normal so I can stop trying to improve it!!!!

I assume a test would be to bypass the vacuum lines around the TV and see if rpms go immediately (or more quickly) to 1600 at cold start. I dont know what a fix would be but it might prove educational.