Bobby, the way I read
that statement from aeromotive – it’s relative to using a hand pump to establish
the vacuum. Since the hand pump develops a very small volume of “static”
pressure difference - any slight leak could indeed “deplenish” its vacuum very
quickly and give poor results. However, when you have a 1300 CC dynamic
pump (your engine) pulling down the vacuum continuously - a slight air
leak around the adjustment screw should not normally be noticeable.
So its my opinion, that
in regular use a normal air leak around the screw would probably not have an
effect – only when attempting to adjust it using an hand air pump.
However, if you have an abnormal air leak (excessive) around the screw and have
your manifold pressure sensor on the same line then it certainly could have an
effect.
I personally run two
separate lines from the manifold (one from each rotor intake), “H” them together
to dampen pulsation and on to the EC2/3 pressure sensors – nothing else on these
two manifold pressure lines. I run a separate line for my manifold
pressure gauge and pressure regulator.
Ed
From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Bobby J. Hughes
Sent: Tuesday, May 12, 2009 9:11
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Fuel Pressure
Regulator \ Vacuum Leak
I reinstalled my EC2
yesterday after a few changes by Tracy. I immediately discovered a new problem.
The lowest MAP address being used was 62 and both primary and secondary
injectors fired at all MP and RPM. With Tracy on the phone and Dennis H supervising my
efforts we found a small vacuum leak at the Aeromotive A1000-6 fuel pressure
regulator. After switching the two MP tubes between A&B controllers the A
controller starter working as expected. The EC2 staged properly with lower
MAP addresses being accessed. When reinstalling the EC2 I had switch the MP
tubes from my usual configuration. A couple of weeks ago I had noticed my B
controller was not working as expected. I had to continually adjust the mixture
to keep the engine running. Now I know why. What was unexpected is one MP
tube is used for the fuel pressure regulator, B Controller and my Advanced EFIS
engine monitor. The Advanced engine monitor was not affected by the slight leak.
On the other hand the EM3 did see the leak and was showing static
pressure regardless of MP. Here is a note from the Aeromotive web site.
NOTE: Testing the enclosed regulator
by applying air pressure or vacuum to the vacuum port with
a
hand-held pump will yield poor
results, due to the slight air leakage through the adjustment
screw
threads. This minute leakage, which
is typical of all adjustable fuel pressure regulators, does not, in
any
way, affect the performance of the
regulator.
Bobby Hughes
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