HELP ! 2.1 Digijet much to lean at higher rpm and load....

I have tested my 2.1 DJ Digijet engine on a Motor Teststand
(Rollenpr=FCfstand in German). At idle rpm it have 2.4 % CO 8 (thats OK!)
but when we pushed it to higher rpm like 3 - 4.000 and we put it under
load, it goes down under 0.3 % CO!!!! Thats not good, you can hear the
knocks inside !

After that we disconnect the Air connection from the fuel pressure
regulator, so the system have more fuel available the CO rise up to 0.9
%!=20
OK thats not they way to fix this problem, but where is the real defect
???

Any ideas ?

Ralf Milewski Berlin Germany