hello
My LS B-Series engine (I dont know about the other Hondas) are running enriched when cold. (without the o2-sensor)

I have a friend who owns a stock 1999 Audi 1.8T, whose car runs 14.7 at idle although the engine is just started.

why is there a difference like this ?

 

What modifications have you done to the engine and ECU?

Rich during cold idle is more than likely an ECT fuel enrichment. the ECU doesn't require the O2 for this type of fuel enrichment. Is your car equipped with a fast idle thermal valve (FITV)? This would normally add more air to mix with the additional fuel in a cold start situation = a higher rpm @ cold idle and a 14.7:AFR.

Also, if the CEL is on for the O2. The ECU may compensate (add fuel) to keep your engine from leaning out.