Saville
Well Known Member
So I was flying around the other day and I flipped to the screen, on my Trutrak EFIS GP FM, which shows Fuel pressure (among other things) and I saw this:
well I immediately flipped on the Aux fuel pump - and saw this:
and I immediately landed.
At no time did the engine falter in the slightest. I was at 5500 feet and the engine had about 149 hours TTSNEW. On the way back I shut off the aux pump and watched the indicator....it hung at 3.8 for just a second and then slowly wound down until it hit 1.9 whereupon it disappeared and displays what you see above. Aux pump back on...immediately comes back on and counts up to 3.8.
In talking with the TruTrak people, this is what happens when there is no data on the line.
Following weekend I pulled the cowl to check all the connections to the Fuel pressure sensor and they all seemed very sound.
So today I went up - within gliding distance of an airport - and took some data. "LEFT" and "RIGHT" mean left tank and right tank. MECH is engine driven pump; AUx is Aux fuel pump on
Startup Reading - just after startup - 1000rpm:
Pump LEFT RIGHT GPH
MECH 2.4 2.3 2.1
AUX 5.1 5.1 3.5
I idled it and got: 2.0 1.9 .5gph
Taxied to the runup area. By the time I got there the readings for MECH disappeared:
Runup Reading - 1800 rpm:
Pump LEFT RIGHT GPH
MECH --- --- 4.4
AUX 4.5 4.5 7.6
5500 feet 23 squared:
Pump LEFT RIGHT GPH
MECH --- --- ??/ can't read my writing
AUX 4.8 4.8 16.0
I may have been too lean here at 23 squared.
Ok so I head back and as I'm letting down I'm playing with the throttle: Prop at 2300.
I bring the MP back slowly to 15" stopping every couple of inches. At 9 inches the readings return - 1.9psi
Back up to 15" - readings disappear.....
Back down one inch at a time - readings appear at 9".
Back up 1 inch at a time to 15...reading disappears at around 12"
I repeat that two more times..same results.
Next time I do it, the readings do not disappear! Odd.
So I concentrate on landing, and take a reading at the hangar just before shutdown:
Hangar Reading:
Pump LEFT RIGHT GPH
MECH 5.2 5.1 1.7
Ok so my first inclination is to say that the Fuel pressure sensor may be bad. It was bought from TruTrak in 2010, 0 - 30 psi
SO# 27614
Looks like a plain old every day sensor:
But it is almost 6 years old.
I can't think of any other things to check. As I say the engine runs fine.
Any ideas welcome.
thanks!
well I immediately flipped on the Aux fuel pump - and saw this:
and I immediately landed.
At no time did the engine falter in the slightest. I was at 5500 feet and the engine had about 149 hours TTSNEW. On the way back I shut off the aux pump and watched the indicator....it hung at 3.8 for just a second and then slowly wound down until it hit 1.9 whereupon it disappeared and displays what you see above. Aux pump back on...immediately comes back on and counts up to 3.8.
In talking with the TruTrak people, this is what happens when there is no data on the line.
Following weekend I pulled the cowl to check all the connections to the Fuel pressure sensor and they all seemed very sound.
So today I went up - within gliding distance of an airport - and took some data. "LEFT" and "RIGHT" mean left tank and right tank. MECH is engine driven pump; AUx is Aux fuel pump on
Startup Reading - just after startup - 1000rpm:
Pump LEFT RIGHT GPH
MECH 2.4 2.3 2.1
AUX 5.1 5.1 3.5
I idled it and got: 2.0 1.9 .5gph
Taxied to the runup area. By the time I got there the readings for MECH disappeared:
Runup Reading - 1800 rpm:
Pump LEFT RIGHT GPH
MECH --- --- 4.4
AUX 4.5 4.5 7.6
5500 feet 23 squared:
Pump LEFT RIGHT GPH
MECH --- --- ??/ can't read my writing
AUX 4.8 4.8 16.0
I may have been too lean here at 23 squared.
Ok so I head back and as I'm letting down I'm playing with the throttle: Prop at 2300.
I bring the MP back slowly to 15" stopping every couple of inches. At 9 inches the readings return - 1.9psi
Back up to 15" - readings disappear.....
Back down one inch at a time - readings appear at 9".
Back up 1 inch at a time to 15...reading disappears at around 12"
I repeat that two more times..same results.
Next time I do it, the readings do not disappear! Odd.
So I concentrate on landing, and take a reading at the hangar just before shutdown:
Hangar Reading:
Pump LEFT RIGHT GPH
MECH 5.2 5.1 1.7
Ok so my first inclination is to say that the Fuel pressure sensor may be bad. It was bought from TruTrak in 2010, 0 - 30 psi
SO# 27614
Looks like a plain old every day sensor:
But it is almost 6 years old.
I can't think of any other things to check. As I say the engine runs fine.
Any ideas welcome.
thanks!