Merlin 140XBL A couple of running anomalies
06-10-2018, 01:32 PM
#1
Merlin 140XBL A couple of running anomalies
Just got back from a 3 day jet fly-in. I had some odd behavior from my relatively low time Merlin140. Startup worked great every time so no issue there. After the startup the idle seemed too fast. It was showing the idle at 38K and change when it should have been 35K. After a couple of minutes the idle would then start pulsating from a high of the 38k and dropping to around 32k. The only thing that would stop the pulsating was to move the throttle up a couple of clicks then it seemed to stabilize at or near the 38k figure.
Second issue occurred several times before separate flights after taxiing up to the runway edge and idling waiting for takeoff clearance. The engine would not respond to throttle stick movements. I kept on moving the throttle stick up and down and after a couple of minutes or so it would respond. Once taxied out on the runway and rolling for takeoff, the engine seemed to respond and run normally for the takeoff and the entire flight. It would begin the pulsating idle again during the somewhat long taxi back to the pits.
Weather was hot in the low to mid 90s. Moderately humid. ECU was set for normal acceleration.
Ideas? Solutions? Anyone ever have a similar issue to either of these?
Second issue occurred several times before separate flights after taxiing up to the runway edge and idling waiting for takeoff clearance. The engine would not respond to throttle stick movements. I kept on moving the throttle stick up and down and after a couple of minutes or so it would respond. Once taxied out on the runway and rolling for takeoff, the engine seemed to respond and run normally for the takeoff and the entire flight. It would begin the pulsating idle again during the somewhat long taxi back to the pits.
Weather was hot in the low to mid 90s. Moderately humid. ECU was set for normal acceleration.
Ideas? Solutions? Anyone ever have a similar issue to either of these?
06-11-2018, 06:48 AM
#2
My Feedback: (1)
Here are some ideas based on my experience.
1. Did you try relearning the ECU to the Radio? If not try that.
2. I have had a couple turbines that had large fluctuations at idle and both times it was a crapping out fuel pump. A new fuel pump fixed it both times.
1. Did you try relearning the ECU to the Radio? If not try that.
2. I have had a couple turbines that had large fluctuations at idle and both times it was a crapping out fuel pump. A new fuel pump fixed it both times.
06-11-2018, 08:40 AM
#3
I found an old email from last year where Gaspar said that for hot conditions to increase the idle speed to 40,000 so I am going to try that for the pulsating idle issue.
I will also try the teaching of the ECU again for the throttle non-response issue.
I will also try the teaching of the ECU again for the throttle non-response issue.
