Hi John,
Once the engine starts running in 50F
temperatures, you should not need the cold start on. At that temp my
engine would flood badly if I left the cold start on for more than a second or
so.
I presume that the 3.9 psi fuel pressure
for the Webber carb is not what you have feeding the injectors? How much
is your fuel pressure to your injectors?
The fact that you need to keep the cold start
on to keep the engine running indicates to me a problem with the injectors delivering
sufficient fuel. This could be because some are not firing properly, fuel
pressure too low, restricted fuel flow or (this happens fairly frequently) the
wiring of the two injector disable switches and their incorporation of the cold
start function may be incorrect.
Normally, when you turn off one pair
(primary or secondary) injectors using the injector disable switches – it
automatically grounds the cold start switch (which turns it on) doubling the
pulse duration to the remaining pair of injectors to double their fuel flow and
meet the engine needs. Also since these switches provide power to the
injectors(say if there was a wiring fault) perhaps only one pair of
the injectors are firing which would mean your engine would be starved for fuel
and would need the cold start on to run.
If this cold start switch function was not
being automatically grounded when you turn off an injector pair using the
disable switch, then the engine would not be receiving sufficient fuel and you
would probably have to use the cold-start switch on the EC2 control panel to
keep the engine running.
So to summarize:
- Both
injector pairs may not be getting
a. Power (+12VDC)
b. Sufficient Fuel (Too Little Pressure or Flow)
c. Grounding signal from EC2
- IF
all four injectors are clicking when you use the EC2 injector simulation
mode then we can assume they have both power and are being grounded
properly by the EC2. In which case that possibly leaves,
- Fault
in the wiring for the disable switches
- Fuel
feed problems
Good luck, this type of thing can have you
tearing your hair out.
Ed
Ed
From: Rotary motors in
aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of John Downing
Sent: Wednesday, September 17,
2008 9:25 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] first start
Yesterday and today I had time to check out the regulators
and the injectors, all are working, had to put a four foot extension on the
stethoscope to do this alone. When I was installing the fuel bypass
tubing there was much discussion, here, on the size of tubing to use,
the directions with the Mallory regulator states to back out the adjusting
screw and run the pumps to see if there is restriction and with the 5/16"
tubing the pressure came to 3.9 #'s, a little more than Lynn stated that the Weber
can take. It would take a month of Sunday's to change the by-pass hose
and fittings to -6 size, so I guess I'll install the after market needle
valve. The project started out with the 48 Weber and Tracy's electronic
ignition system to fly 4 years ago and eventually install the fuel injection as
a winter project at a later date. Life gets in the way of living and
plans change, so l have both carb and fuel injection, using the Weber as a
throttle body, or carb, if the injection system fails. Enclosed are two
photo's of the carb, over the top manifold, with the fuel injection hidden
beneath the intake manifold. My machinist buddy made two plates of
aluminum to level the carb on the intake manifold.
How long on the average do you need to run the engine in 50 degree
weather before it will stay running with the cold start switch off?
(fuel injection) I will need to add several items on the after start
check list, as in all the excitement many things were overlooked and in all
this checking, you notice things that didn't quite get finished as distractions
arose, there is a positive note in every thing.
That gasohol is some nasty stuff, it looks like a cloud
floating around in it and I got some on the pressure gauge face and it turned
it to slime and when it drips, it looks like olive oil and the odor is
terrible. JohnD
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