[Two Tone]

Why not revive this thread for another year?

I have a CIS question for Souk (or whoever wants to answer).

First let me state that I'm aware that the CIS is a SYSTEM and that there is a proper procedure for trouble shooting, ie. control pressure testing etc. I also have the Bentley manual and I intend to go about this in a systematic way.

That being said, I'd like to describe my problem and benefit from any wisdom that comes my way. Here goes:

I have a 78 SC engine that came from a warmer climate. I'm in Eastern Canada and spring and fall temps in which I still drive the car can be a little below freezing once in a while and very often in the 40 - 50 range. It seldom ever gets above 85 F here in the hottest part of the summer.

Firstly, the car runs very well when warmed up, idle is right at 1000 and smooth, performance is great. I don't know how the mixture is but there is a fair exhaust odor. I'd say its a little rich if anything but I'm guessing here.

Secondly, warm starts are also fine. Starts with a bump of the starter, idles fast for a few moments 1300 - 1500 and then settles back down to 1000 or so.

My problem is with cold starts and warm up:

With a cold engine, it takes a fair bit of cranking to start the engine. It may cough a few times and take 3 or 4 attempts before it catches. It will run very roughly for a few moments (10 seconds or so) while missing and popping (pop-off valve is a good thing!) at about 600 - 700 RPM, then very suddenly it will smooth right out as if all cylinders suddenly came on line and it roars up to 3800 RPM. It will run at this speed for approx 1 minute and then very suddenly it drops to about 1300 and then slowly settles to 1000. Its just as if you were holding the throttle open to run it at 3800 and then took your foot off the pedal. Its very sudden.
During the rough start up phase before the high rpms kick in, applying throttle has little effect. While in the high rpm phase, thottle works normally, ie. if you push down on the pedal, the rpms will increase past 3800, (not that I do this). Exhaust smells very rich while this is going on.

It seems to me that something is a bit out of whack here. While this does warm the car up quickly, 3800 rpm is just a little harsh on a cold engine and it takes too much cranking before it starts. (At least its already built up oil pressure from all the cranking before it soars to 3800).

On a partially cooled down engine (sitting for an hour or so) I'll get a less extreme version of this. That is, it starts first try, stumbles a bit and then revs up to maybe 2500 or so.
A few times when the ambient temp was 80 ish, it cold started like you would want it to, high idle of about 1300 - 1500 and then dropped to 1000.

Its seems obvious that one of the CIS components is controlling this very high warm up idle and needs to be adjusted or repaired, but which one? Is this most likely a WUR adjustment issue?

Any info much appreciated.

I should mention that plugs, wires, cap and rotor are new and valve lash is correct. The problem was the same before and after.

Sorry for the novel.