TBI - bench adjust fuel pressure regulator?

I saw that someone did a pre-setting of an adjustable fuel pressure regulator using an air compressor. The thread was called "Vacuum Adjustable TBI Fuel Pressure Regulator" that had a statement in "There was a guy here awile back who dialed in fuel pressure on a TBI on bench with air pressure. Pretty sweet setup he made from parts laying around. Was same pressure in truck with fuel when he was done."
Has anyone else done the air test to find out what pressure the regulator is running at with a TBI set-up?
I built an air fed system used things I had around the shop and an inline fuel pressure gauge. I used an adjustable pressure regulator to feed the TBI because I was pretty sure I should not be forcing 120 PSI through the TBI regulator.
When I set the air regulator set to 17 psi, the fuel gauge reading at 9.5 psi.
When I set the air regulator set to 22 psi, the fuel gauge reading at 10 psi.

What air pressure should I use when testing?
Should I be using the same pressure as the max output on the fuel pump?
If so what is that on a TBI system?
Thanks, Mark J

I did a little digging around. A friend of mine that works on stock repairs said that one time he had a gauge on a TBI and pinched off the return line an saw the pressure go up to 30 PSI. So I tried to do my setting @ 30 psi air pressure. The old non modified TBI read 12 fuel psi.
My 1990 K1500 was running out of fuel on hard low end pulls. So I set my adjustable for 13.5 psi.
I'll see if the actual fuel pressure turns out to be the same once my mail order "fuel filter to engine" fuel lines come in. The old original line looked like they would have sprung a leak if you looked at they wrong. Yea, that rusted!

Yeah I'd guess pressure had to be way above what regulator spring is capable of. I know the thread you were referring to and it worked well.

When adjusting a TBI regulator I usually just do it on the vehicle with the injector pod attached to fuel lines and adjust. Then bolt it on TB. Use the red wire off fuel pump relay to power it so fuel pump runs constantly. So I never built an air pressure set up like above.

I finally compared the air setting to the real fuel. They were close but the pressure was about 3/4 of a pound off.
I showed a little over 10 PSI on air with incoming air set at 24 psi. When I put the TBI on the truck with the same fuel adapter/gauge from CFM the gauge showed 11 PSI.
It works but not as close as I would like to see it.

I always wondered if air and fluid would be the same. Thanks for verifying and sharing the results.

No Problem.
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