Afr bt50

I’m reflashing a bt50 3.2ltr using alien tech I’m making the power I want but the afr seem to be all over the show and I can’t seem to get a handle of it. Start of a run they will be 19:1 then through the mid range and top end dips down into the 15. I’ve got the rail pressure back to factory and still no different

any recommendations would be appreciated

It's not unusual to see a non-linear AFR curve in a diesel engine. the principle essentially is that more fuel (within reason) will produce more power but also create more heat since we're starting well on the lean side of stoichiometric. I wouldn't recommend going richer than approximately 1.10 lambda for use where the truck will be potentially towing loads.

Can you actually make changes that affect the AFR or are there tables missing from the definition?

I have control over fuel quantity,injection ms,injection timing and rail pressure I think I can see where I’ve made my error as I’ve increased the fuel quantity it increases the ms for a given rail pressure hindsight is 20/20

cheers for the help