As Jay said its very important to get it setup correctly...
With my trusty (now deceased aem wideband) & greddy egt, i setup a td04L on my car to run 1.7bar with the following:
sard rrfpr
7m fuel pump
324cc injectors
Jam ecu set for ct9 hehe
fuelling was spot on, also egt was never over 760deg Celcius... now this was on a very controlled system, ie we where very careful what we did, also since i had stock rods i didnt rev it over 6800rpms.. u can throw almost anything u like at any jam ecu & it will try to obtain the best af. .as the eprom they have works on a very similar effect as a/f target.. BUT dont take my case as a general rule, have it tried & tested, or u may be sorry down the line..
kon