Fuel pressure testing 88 Civic CRX DX

Just wanted to add to the growing content in this group for do-it-yourself mechanics.
I became frustrated trying to find a way of testing the fuel pressure
of my 1.5L honda DPFI (throttle body).
The bolt size of the "service bolt" on the fuel filter is 6mm. I couldn't find a way of adapting to this port with the fuel pressure tester that I had short of ordering a very expensive Honda part that would be two weeks out. Hence, I went to the wrecking yard and got a made-up fuel line that goes from the the filter to the throttle body. I cut this roughly in half and installed a 1/4" barbed "T" with a threaded hub (came in the Pressure test kit). I replaced the original fuel line temporarily with the test line and installed the pressure tester. I placed a two-by-four across the engine compartment and under the hood, snaked the pressure test guage under the hood onto the windshield and drove the car around the block a few times and observed the pressures on the guage...when I accelerated the guage pressure would decrease.
Would someone please explain the relationship between pump pressure, regulator pressure and volume of gas used associated with acceleration?
Thanks, Tich
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The regulator is a bypass regulator, so the pump is always (supposed to be) putting out way more gasoline than is needed. The regulator shunts most of it back to the tank and lets the injector system take what it wants.
(Background) In multiport injection, the regulator has to maintain a constant pressure across the injectors. The injector tips are at intake manifold pressure, so the regulator has a connection back to the intake manifold. The rail pressure is lowest when the manifold vacuum is highest, and the pressure goes up as you open the throttle because the manifold vacuum drops. Pressures in the 40 psi range are typical.
I've only messed with one throttle body injector, and that was in a Taurus (shudder!), but.... The injector operates at essentially constant pressure. IIRC, it was less than 10 psi in the Taurus. The injector tip is at essentially outside pressure so there wasn't any vacuum compensation. Yours may be different, though. If there is a vacuum line from the throttle body to the fuel pressure regulator, it may be normal to see the pressure drop at large throttle openings. If there is no vacuum compensation line and your pressure is dropping I would suspect a dirty fuel filter.
Mike
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