On power on (to the TCU) my servo will open and then fully close the
wastegate one cycle.
With the engine off and the TCU on, I can advance my throttle from 0% up
to110% and the servo will make small changes.
When I look at the servo (the pully piece on the top), the cable
connections and drops to the right hand side. When the servo moves, it
turns the pully piece to the right.
That loosens the cable and allows the spring to pull open the
wastegate. If the gate is stuck (not in this case), then the cable will
bow out at the pully piece.
Hope that helps some..
Matt Carpenter
Jim Butcher wrote:
>
>While doing full power tests with our 914, we have found that the manifold
>pressure
stops at 30.5 inHg even at full throttle - 5800 rpm. Watching the waste
gate lever from outside the airplane, we observe that the waste gate does not
change position from idle (2000 rpm) to full throttle.
>
>Further, when power is applied to the TCU, the servo motor rotates about 45 deg
towards waste gate closed, then rotates the opposite direction about 90 deg
and then rotates in the original direction about 45 deg. In other words, the
waste
gate is not closed at power up with the throttle closed. If I adjust the
cable so the waste gate is closed at power up, it will still attempt to rotate
both ways as before and when it stops, I get a flashing red light. The servo
does not change position when the throttle is moved from idle to 115%. I have
checked the throttle position with the TLR46 program. By the way, TLR46 says the
servo is at 50%.
>
>All these symptoms are with a new engine on initial run-in. I have double
>checked
wiring and connections. Shane at Lockwood thought the servo motor was defective
and I installed the replacement this morning with the same results.
>
>Can anyone make any suggestions or lend some trouble shooting tips?
>
>Thanks
>
>Jim Butcher A185 N241BW
>
>At airport trying to fly!
>
>
>
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