Fuel rail question. Mixing up the years ;)

Hey guys!

I have a quick question.
I am stroking my 90 renix 4.0. I have an edelbrock head and 99-01 intake. Can I use an inline fuel filter with the built in pressure regulator and use a 99-01 fuel rail and stock fuel pump, or do I have to stick with a 91-95 fuel rail that has a vacuum regulator?

I don't know anything about the inline filter with built in pressure regulator, but I suspect that the root issue is a return line.

I think that as long as you have a return line from the regulator you can do it. The '96 and later XJs don't have a return line because they have the regulator in the tank. For those vehicles if you attempt to move the regulator out of the tank you need to add a return line.

I don't know how a Renix XJ handles fuel pressure, but if you already have return provisions in place and can tap into those then I think you should be fine.

That is my limited understanding of the situation. If someone knows more then take their advice.

ECMs in general really can't compensate well for switching from a varying fuel pressure system to a static fuel system. The shape of the curves are completely different and the trim variables that are available to it aren't suitable for making the adjustment. Short of adding some sort of piggyback controller, it will be all but impossible to tune a Renix to run well across a usable operating range with a static fuel pressure. You'd certainly be shooting yourself in the foot right before the grueling march that tuning a Renix already is.

The filter with the regulator has a return on it, so two connections on one side and one on the other.
I did some more digging and it seems like renix and pretty 96 ho runs the same 31psi. 96 and up runs 49psi.