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On 05/07/2011 05:57 AM, Lehanover@aol.com wrote:
Good job on the trouble shooting.
Lynn E. Hanover
I'll
probably start rambling, but I've spent the past two days
covered
in gasoline, so I have an excuse. Jumping in and out of
the plane to
turn fuel valves, try to bleed lines, or switch on pumps
has me beat down.
What I lack in intelligence, I make up for with
stubborness.
Today, Lee, my younger son, helped me set the fuel pressure to
45psi. I couldn't watch the pressure gauge while fiddling with the
regulator, so he called out the numbers while I adjusted. The
regulator is back in a hole. I don't believe he has any idea how
grateful I am, or how much work he saved me by turning a 2-hour job
into a 3 minute task.
The next thing on the agenda was "characterizing" (my term) the
injectors. The Megasquirt has an injector test function. You tell
it how long to fire the injectors, and how many time. Set it to
fire ten times or so for a few milliseconds to verify clickety-click
from the injectors, or set up a fixture to capture and measure the
sprayed fuel, and you should be able to tell exactly how the
injectors are behaving. I'm not the type to pass up that sort of
useless information.
s = milliseconds sprayed
f = nominal flow
m = missed flow due to turn-on/off time
c = cycles sprayed
c(sh-m) = measured volume
The two unknowns are m and h. Do it for several s values and you
have a series of equations that you can solve for m and h.
That was my goal. I got several good runs, but when I set s to
80, the program bailed on me. Said 65 was the highest I could set
it to. Unfortunately, from that point on whenever I turn the MS
on, I would get full fuel flow. I wasn't able to turn off the
test mode, change it to something else, or switch it to normal.
Today was going to be my first run of the engine. Unfortunately,
I ended up having to reflash the firmware, and reconfigure all the
computer settings. It is back up and running now, and I did just
a basic test of the secondary injectors. I haven't even had time
to boil the numbers down to see if they make sense. The injectors
all measured out very close together, so I'm confident they are
going to service me well.
The raw numbers from the primary injectors (only one test on the
secondaries, and they looked the same).
400 5ms squirts gave 15ml.
400 20ms squirts gave 60ml.
1600 5ms squirts gave 48ml on one injector and 49ml on the other.
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