High nox on new stroker 4.6

[Tonyt22]

So I finished my stroker 93 block with 98 head 24lb injectors
All new sensors ,battery, temp sensor relocated to t stat housing ,
.has been running great no check engine lights power all thur the rpm range .
Only problem I'm having is high nox so failing smog
Thought maybe was a issue with a exhaust leak at the flange but fixed it and replaced my cat and still failed thinking might be a fuel issue ?
My scr is 9.3
Think a adjustable map would help ?
Is their any standalone ecu that I can run that i could possibly tune as well

[Cheromaniac]

Your results are consistent with an engine that's running lean.
I don't think a MAP adjuster will solve your problem 'cause you'd only be able to enrich the AF mixture at >70% throttle. However raising the fuel pressure with an adjustable fuel pressure regulator would enrich the AF mixture at any throttle opening and reduce your NOx emissions.

[Tonyt22]

Your results are consistent with an engine that's running lean.
I don't think a MAP adjuster will solve your problem 'cause you'd only be able to enrich the AF mixture at >70% throttle. However raising the fuel pressure with an adjustable fuel pressure regulator would enrich the AF mixture at any throttle opening and reduce your NOx emissions.

Thanks for the quick reply
Is hesco the only afpr available for a 93 ?
Can't seem to find anyone else
Would a fixed pressure regulator be good enough like
PR211,
PR209 they operate at 50 and 55 psi ?