I have a SECU gold computer and I just installed DSM 450s with a high flow rail. Calibrated on the stock B16 fuel map, the air fuel ratio hovers around 18 at idle. I have a fuel pressure gauge and it tells me right around 30 at idle (on a B16A in a CRX). I double checked the wiring, I tried to bring the air fuel ratio down but I kept having to add a lot of fuel but that shouldn't be right. (?) With the stock injectors, air fuel ratio was 14.7 at idle (perfect). I need help please. Why is this happening?

 

Because of the inertia of the injectors at low pulse durations. There is a large moving mass, and a straight percentage cut will run you lean from stock injectors.

...it is natural to have to increase fuel at idle about 5-7% on 450cc injectors over the percent difference (46%) from 240cc injectors.

 

i gave it 10 percent at idle and it was still around 16 A/F would this still be normal? also the injectors were balanced and blueprinted.

 

8.6% is one AFR point... I.E., if you're at 20:1, adding 8.6% will bring you down to 19:1... get what I'm saying?