Let me begin by saying a did a search, and found lots of info out there.....Unfortunately a lot of it varies.

What should a bone-stock fuel pressure be? I'm getting a rock solid 36psi with it idling and maybe about 43psi with the key in and the ignition off. I've seen people say 40, 43, 45 and hell I see a few 50psi recommendations.

I realize that there are afpr's out there, but they are junk as the computer will adjust.

I believe the school of thought that the fuel pressure should be on the high side of factory spec to get better fuel atomization, however I realize that the volume of fuel will eventually return to the same because the computer will pull a few ms off the injector duty cycle.

Having said all of this, what should a stock Z28 (94-97) have:
- Key on, Engine off
- Idling
- WOT (Idling w/ vacuum pulled to fpr)

I had to replace my fpr a while ago and I have a feeling this one's crap too (it's just a stock oem replacement)

 

Fact: static pressure from the pump should be 41-47 psi This can be measured with engine not running, having clicked the key ON a few times to make sure pressure is stabilized (or by jumpering the fuel pump prime connector to 12v).

Pressure will normally be less than that at idle and will vary according to engine vacuum. 36 at idle is ok as long as idle is stable.

WOT pressure can be in the same range as in paragraph one. Monitor idle pressure and then remove the vacuum hose to the regulator. The pressure should rise to the above range. This indicates the regulator is at least doing something.

Your readings sound normal to me.

 

Thanks Rob :-)

I just went out there and verified mine as follows:

At idle: 36psi
with vacuum removed: 44psi
key on, engine not running: 36psi. It does jump from ~40ish but as soon as the relay clicks it goes back down to 36psi.