Fuel pressure at the test tee should ONLY be "dead on [the Bentley] spec"
IF your manifold vacuum is "dead on spec" AND you are at sea level.  If you
don't have proper manifold vacuum you can buy all the new fuel pressure
regulators (FPRs) you want but you'll never get 28 psig at idle.  A
functional FPR simply maintains the fuel pressure a constant 36 psi above
manifold  vacuum [as pointed out by Beierl].

That said, Michael's case is kind of special.  He is about 3 psi ABOVE
specs with the vacuum hose connected AND disconnected.  Provided he doesn't
live well below sea level, this SEEMS indicative of a faulty FPR rather
than a manifestation of poor vacuum.   If one has a good FPR but inadequate
manifold vacuum the fuel pressure measured with the vacuum hose connected
will be above spec, but the fuel pressure measured with the hose
disconnected should be close to 36 psig at sea level.

Scott Terry
'85 Westy "Pearl"
Santa Barbara, CA

P.S.  I think Michael meant to write 39 psi unconnected and 32 psi
connected below?
P.S.S.  psig means psi "gauge".  If your vacuum/pressure gauge reads -0- at
sea level then the units are psig (g for gauge).  If your instrument
indicates +14.7 (psi) at sea level then the proper units are psia (a for
absolute).
PS3:  Plugging the manifold vacuum hose during the hose-disconnected FPR
test shouldn't affect the measured fuel pressure--just maintains manifold
vacuum and keeps engine from surging, keeps engine happy.

Michael wrote:
>> I have one of these vacuum guages and I have borrowed Robert Lilley's fuel
>> pressure guage, so I will give your test a try next week.  I measured it
>> last weekend at 32 psi unconnected and 39 psi connected -- slightly too
>> high but not enough to worry about, I hope.  I forgot to plug the manifold
>> vacuum hose, though, so I need to repeat this measurement.  (What does the
>> g stand for in psig?)

Matthew responded:
>Wait!  Slightly too high? Like how much? 3psi is about 10%... follow that
>through and it means 10% more gas in the injectors.... It should be dead
>one spec.  A bit high (on two independent gauges) is not acceptable. I've
>been down this long road before....