I have searched, but I cant actually pin point symptoms of a bad FPR.

What car problems arise from different ways a regulator can fail? Example, one that doesnt hold pressure for long after the pump is off.

 

FPR failure is rare. Most problems are actually caused by leaking or disconnected vac hoses. This will cause fuel pressure to be fixed at the static pressure instead of rising and falling with manifold pressure as it should. The engine will run rich under vacuum and lean under boost.

Why don't you tell us what problems you're experiencing and we'll tell you if it's the FPR.

 

my regulator went bad just reasantly and it just showed static pressure the whole time. now when I went to install my aftermarket fuel regulator I did make sure the vac lines where secure and sure enough they where very tight with zip ties on both ends of the vac hose.

 

The free, online, S5 FSM says the pressure in the rail should be at least 18psi after the rail has been pressurized and then the key turned to OFF. See section F2, page F2-46 for trouble shooting the cause of the pressure falling too much.

I think this step is left out of the S4 FSM.

 

Well the reason I posted this is becaus I have a S4 that I couldnt get to run properly, even after I installed a new motor. After a long headache trying to find my problem with flooding, I found the AMF was keeping the fuel pump enabled, I adjusted the tension spring and now only closes the circuit when the door is open on the AFM, but now I cant even get it to start.

I tested the pressure, when tee'd....it was at 38 psi, then quickly dropped to 20 before staying there for some time. I was trying to keep this simple and not double post, but below is the link to my other thread for more details. Ever since I fixed the AMF problem...the car wont even run now, I figured the pump always being on may have damaged the FPR.


https://www.rx7club.com/2nd-generation-specific-1986-1992-17/help-rough-idle-smoke-new-motor-same-problem-482517/