Ok, I have a 74-2.0 still injected and wanted to know how critical the exact 29psi is? If I was like 30 or 31 lets say....would it run rich? or if I was 27 or 28psi...you get the idea.
My gauge shows just a hair above 30psi....should I care?

Thanks
SW

The amount of fuel injected is a function of fuel pressure and the milliseconds that the Injector is triggered.

So, yes

Adjustments in fuel pressure can effect whether the car is rich or lean.

I have set them as high as 32 psig. At some point, the fuel pressure will over-ride the control spring in the injector making it like a mechanical injector. I don't know where the upper point is.

I think the spray pattern changes at some point as well. It definitely does on the low side; at low enough pressure it will dribble rather than spray.

Higher pressures supposedly can lead to injector leaks earlier than the standard pressure.

No real idea on what exact numbers are "low enough" or "too high", though.

--DD