'83 CIS cold start low idle issue

[AndreasK]

Maybe this problem is more common than expected. My AAR works as intended, apparently. Open when cold. Closes fully after a minute or two. Won´t idle when cold, without feathering the throttle. With throttle I can keep it steady around 1100 rpm. Idles by itself around 950 after a minute, but hunting slightly, while warming up. Steady idle 950 when warm. I suppose its running slightly rich until warm. Runs great when warm. Tony´s smoke test next. Has anyone removed the CSV flange without dropping the engine? Or am I best of waiting until I at one point do drop it? I haven’t, at the time, got any other reason to drop it, and I can live with the car running as is for a while.

[wreckah]

i removed and drilled the csv flange without drop. It is NOT fun

[AndreasK]

Originally Posted by wreckah

i removed and drilled the csv flange without drop. It is NOT fun

Sweet. It´l depend on my mood towards spring then

[JB]

I did a partial drop (lowered the rear of the engine a few inches) and got the CSV flange loose but the hose attached to it was so stiff, I couldn't get it loose. After all that work, I ended up dropping the motor anyway. So much easier, especially the CSV install with motor removed. Incidentally, when I got everything back together, the decel valve was not working properly producing a continuous high idle. Unplugging the vacuum hose (and plugging it) brought everything back to a nice idle. My take is you don't need the decel valve anyway.

[JB]

Incidentally, I have found 3 CSV flanges in my spare parts jungle and they were all the closed variety even though the systems they came from were later US or Euro CIS. Makes you wonder...

[boyt911sc]

Originally Posted by JB

I did a partial drop (lowered the rear of the engine a few inches) and got the CSV flange loose but the hose attached to it was so stiff, I couldn't get it loose. After all that work, I ended up dropping the motor anyway. So much easier, especially the CSV install with motor removed. Incidentally, when I got everything back together, the decel valve was not working properly producing a continuous high idle. Unplugging the vacuum hose (and plugging it) brought everything back to a nice idle. My take is you don't need the decel valve anyway.

JB,

You could remove the decel valve if is defective or leaking. But you need a good working DV. People who removed it does not understand how a good working DV plays an important role in the operation of CIS. If you strongly believe that there is no need for a DV in your engine and would make you happy, nobody could stop you from doing so. It is your car and not ours. And I won’t do it for my engines. The lack of understanding and knowledge is difficult to overcome. Keep us posted.

Tony

[JB]

Tony,

Lack of understanding and knowledge is not difficult to overcome if someone such as yourself is willing to explain it to someone interested in learning.
Please enlighten me as I am always interested in learning.

Jim