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Hi Tommy, was wondering why you didn't show up - good reason! Just a
couple of thoughts - fuel pressure fluctuation could be due to:
1. Heat build up in fuel causing it to percolate and fuel pressure
fluctuations - unlikely on a day like today with the lower temps though.
2. Fuel Regulator malfunction causing varying fuel pressure (and amount
injected)
3. Leaking injector (sticks on and you get rich reading - might also cause
a pressure drop)
4. If injector sticks open then A/F LEDs would probably be full rich and
possibly the fuel mixture knob would not make any difference as in effect
all it does is affect the injector pulse width - which if the injector is
sticking open - won't have any effect)
5. All I could think of for the moment
If I had to pick one at the moment I would check out a leaking injector. If
you have EGT in each exhaust port, the next time it happens check and see
if one EGT is not reading several hundred degrees lower than the other.
Glad you made it back without further incident.
Ed Anderson
----- Original Message -----
From: "Tommy James" <twjames@statesville.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, December 04, 2004 6:15 PM
Subject: [FlyRotary] Re: power sag and fuel pressure saga.
Okay, here's my saga for the day to go along with Steve's
I departed 31A heading for 28A, famous as the Rotary mecca of NC and home
of
Ed Anderson, OAT 55*, coolant at 180 or so. Cruising at 25x25 when the red
EIS light blinks a warning fuel pressure at 45 or more. My GPS had ceased
operations for the day, but I had just passed RUQ. I knew where I was,
more
or less. I turned and made a precautionary (read puckered)landing at RUQ.
Fuel pressure fluctuating from 42 to 52.
The cowling came off, I always carry a few tools, and I checked the
connections for the fuel pressure gauge which were secure and showed no
change. A visual inspection of the fuel system showed nothing unusual and
everything was cool, literally.
After sitting for 30 minutes or more the fuel pressure read 31 with the
pump
and engine off. Not understanding anything more, I put the cowling back on
and fired it up. Hard start(longer crank time)so I used the cold start
option. Cranked right up now, but the mixture meter is off the scale
rich..
Not running very smooth with misses obvious. B controller produced no
change. After a long taxi, the temp is up to 150 or so. Fuel pressure now
showing 36 which is normal. Adding backup pump took pressure to 43. Things
look normal again. Departed with sun in my eyes so I could not read
mixture
meter, but I know it was about 8bars as I started TO roll. Climbed out to
the north and noticed mixture meter was off the scale rich. Moving the
control to 9 o'clock made absolutely no change in mixture or performance.
(this is usually enough to cause a stumble) The short flight back home
was
uneventful, except for my wondering what would go off next. Electing to
climb as much as possible, I was at 4500 and 7 miles out, so, the low
power
glide might have cleared the engine as it ran smoothly after landing with
mixture reading normal 6 bars. Fuel pressure back to 32 at idle.
Soooo, does anybody have any insight? I'll go out tomorrow PM and test
everything and fly for effect.
Thanks to all,
Tommy James<><
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Steve Brooks
Sent: Saturday, December 04, 2004 3:28 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: power sag
Tommy,
I'm not certain about the coolant, but the oil was barely 130F, the
coolant
was pretty low.... maybe 140 or so if I had to guess.
Steve
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On
Behalf Of Tommy James
Sent: Saturday, December 04, 2004 2:26 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: power sag
Steve, What was the coolant temp at takeoff? Sounds like the engine went
lean with the cold temperature and boost. I'd make sure it was 'super
rich'
for takeoff, like 8 bars or more on the EM2 mixture meter.
Regards, Tommy<><
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