The knob on the ECU, I thought, is used to adjust the mixture of fuel/air?

I have it all the way clockwise, but changing it appears to not give any noticeable difference in the way the engine runs. Trying to chase a bad cold idle and trying to eliminate that as a possibility.

Can someone educate me in the proper usage of that knob and what effect rotating clockwise/counter-clockwise will have?

Thanks

It is not fuel/air mixture. It is rich/lean fuel. Can't remember which way is what though.

Now that I think about it I believe clockwise is rich, counterclockwise is lean.

It is strickly for the idle circuit as I understand it

Clockwise richer, counterclockwise leaner.

Start in the middle of the range. One click at a time richer or leaner. Must run for a couple of minutes to stabilize.

Idle only.

If it's not making much difference when you adjust it, there might be some other issues going on. Here's a link to Brad's site. Some where on here, he goes over this.

http://members.rennlist.com/pbanders/DJetParts.htm

Your TPS must be set correctly for your adjustment knob to make any changes

Yep! The throttle position sensor must be properly set before the idle mixture screw wil make any difference. ECU knob will not make any difference in the way it runs, but a maladjust on the TPS will! Your crappy cold idle is more likely to be the head temp sensor.

actually, after removing the air cleaner assembly yesterday, I was able to see the CHT sensor better and it appeared to have oil around it where it screws in. Does this indicate anything and should it be replaced?

Sure your looking at the CHT ? Shouldn't be any oil out there, and if there was it should be burning off, and you'd have a hell of a leak somewhere.

I'm betting your looking at temp sensor 1, not the CHT (temp sensor 2). #1 is locasted below the plenum on a bracket. The cht is screwed into the head beside the #3 plug. It's screwed into a blind hole. There should be no oil there. Oh wait, you could be looking at the oil pressure sender. It could have lots of oil on it.