cis co reading question...
 

Hello all,

In trying to overcome my off idle stumble, pop, bog then run ok after 3000 rpm problem, Ive found to what I think is a very lean condition. About 2000 rpm my meter shows .6 to .9%co.

I have adjusted the idle co to about 2%co (per text) and it runs really lean off idle.

My question is there a way too adjust mixture for mid range? What would cause a midrange lean condition. Does anyone know what is optimal CO% for off idle (2500-3500rpm)?

My fuel pressure testing set-up that I ordered last week is not here yet. I am sure I will find out more once I test the control pressure circuit.

The car is a 74 911 2.7 BTW. Less than a mile on a total rebuild.

Thanks guys,

Chris

Wait until your pressure gauge arrives, then you can really see what's going on. Gotta have the right tool to do the right job.

Steve

What ever happened on this? What was causing the >3000rpm stumble? I'm having the same problem and have a Gunson on the way to test CO levels.

Sounds to me like the air flow paddle is getting fouled on something or is binding. This could cause leanness off idle

From what I understand it's far more common of a problem running too rich at idle.

I'll be interested in reading what you find out about this running too lean at idle (below 2,000 rpm).