Okay, installed some new Ford 5.0 injectors awhile back on my 5.7 TPI. Got those because they had a good deal on them. They work fine, but I barely passed smog. Seems that too much fuel is getting sent to the engine. I understand that the Ford and Chevy injectors have different flow rates under different pressures. Is it possible that the stock pressure for the 5.7 is causing the Ford 5.0 injectors to delivery too much fuel? I also seem to be WAY down on power. Should I get an adjustable regulator and turn down the pressure a bit? Any advice would be appreciated.

 

Ford injector rates are calculated for a lower fuel pressure than Chevy. They will work, but you just need to let your PROM tuner know. You will need a new PROM, like previously said.

 

So this can't be fixed by an adjustable fuel pressure regulator?

 

I don't believe your Ford 19 lb. injectors are the problem. If you have a rich condition. You may have a bad O2 sensor or another EFI problem. I would look somewhere else. I have never really seen it written in fact that Ford rates their injectors any different than GM. If you do any testing on Fords currently in use the fuel rail test pressure is 37 -45 psi. kind of like our TPIs huh. Before I installed my AFPR my pressure was 38 psi at idle and 42 psi w/o vacuum applied, the same as my son's Mustang GT. I believe most injectors are tested at 43.5 psi. If I'm wrong I'd like somone with a little positive test data to join in. I as well as many others are run Ford SVO 24 lb injectors because they are economically priced. Even running 48psi fuel rail w/o vac I have my injector constant at 25.7 and I pass emissions with no problem