I'm, quite sure my EC2 knows whether or not there is power supplied to
the injectors.

With the engine warmed up and idling with the cold switch off, when I
turn on the cold switch the engine will run very rich and die.  This is
expected, of course.  

Again with the engine warmed up and idling with the cold switch off, if
I turn off the power to the secondary injectors and turn on the cold
switch, the engine continues to run fine.

Once again with the engine warmed up and idling with the cold switch
off, if I turn off the power to the primary injectors and leave the cold
switch off, the engine dies starved for fuel.  This again would be
expected.

Finally, with the engine warmed up and idling with the cold switch off,
if I turn off the power to the primary injectors and turn on the cold
switch, the engine continues to run fine.  In this last case, the EC2's
staged indication indicates operation above the staging point even
though the engine is idling and the stage threshold has not been
reprogrammed using mode 7.

In both cases where the cold switch is on and one set of injectors is
not supplied with power, the engine runs fine from idle to full throttle
which is above the staging point but only 24 inches of manifold pressure
at my location.

In the end, I'm not sure it matters so much that we know exactly how
that crafty Tracy has accomplished the fuel injector backup function,
but it is important that we know how to use it properly for the way our
particular systems are set up.

Steve Boese


-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Bob White
Sent: Sunday, July 05, 2009 5:27 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Below staging


Still catching up on messages!  This is the last message that I've found
with this heading, and I think I can clear this up a little bit. This
isn't OFFICIAL from Tracy info, but it's what I think is happening.
Also, for now assume this is all for testing and there isn't really a
problem with the injectors.  Reduces the number of "but on the other
hand's". :)

The EC2 doesn't know whether the injectors have power or not.  It know
two things relevant to this discussion.
1) Is the cold start switch on or off, and
2) are we above or below the staging point.

If the cold start switch is on, then we should double the gas flow.  

If below staging, we can double flow by turning on the second set of
injectors.  Now if cold start is on because you disabled one or the
other set of injectors, then both sets will be triggering at the same
pulse width as before, but only one of them will have power so gas flow
will be correct.  This is really handy as we don't have to worry about
which set of injectors is turned off since with cold start on all of
them will be working.

If above staging, we would have to double the pulse width to double gas
flow.  Again if one set of injectors is turned off, then you have 1/2
the injectors suppling twice the flow so gas flow is correct for that
situation also.

Of course it doesn't quite work right with different size injectors for
primary and secondary, so a little tweaking of the mixture control is
necessary.

Bob W.  (Only 116 unread messages to go)