Fuel Pressure Issue Please Help

[96chevy7.4L]

Hi everyone. Back again maybe someone out there can advise me on an issue. My 96 chevrolet C3500 has the vortec 454. The factory fuel pressure setting is 60-66psi. I have added bigger injectors and a bigger throttle body. The injectors are according to delphi and injector upgrade for my engine. MY issue is when checking the fuel pressure at the fuel rail it only reads 50psi. Is this an issue and would it trigger a check engine light which it has done. Could the lower fuel pressure cause the injector to droplet fuel in the combustion chamber instead of the fine spray that it is supposed to release. Any thoughts on this would be great. DO I need and adjustable regulator or better fuel pump. When I had the upper intake off to put the injectors in I replaced the fuel pressure regulator. Once again any help appreciated.

[merlin5577]

I will be the first to admit that on the 7.4L in your truck I have very little experience. But if there is one thing I know it is engines, so I will try to help. With the modifications you have listed, I believe your problem is the tune on the engine. The factory PCM is configured to the stock sized injectors, so when it sees an increase in fuel flow but a decrease in pressure it thinks there is a problem. This, coupled with the added airflow your new throttle body is providing is what i believe is causing your check engine light. An adjustable fuel pressre regular will help with tuning but I dont believe it is necesary. I noticed in your signature you listed you had a hypertech programmer, does that programmer allow you to compensate for the larger injectors? If not, you will need to either buy a program to tune the truck yourself, or pay a shop to do it. On a side note, whenever you change injectors it is a good idea to change your fuel filter. Nothing worse then ruining you expensive new parts over a $10 filter. Hope this helps. Good luck.