914 Turbo Troubleshooting

[DavidOber]

When I purchased my 2014 P2008, it would only produce about 37" manifold pressure at full throttle.  I assumed it just needed a cable adjustment.  When I brought it to SportAir in Little Rock for the parachute install, I asked them to look into it.  After much troubleshooting (TCU adjustment, TCU swap, Lockwood calls, Tecnam calls), they finally realized the boost would either stay low or stay high.  They took the turbo off and discovered that the waste gate "hinge" was "gunked up" and was not either closing or opening fully.  The mechanic has a video on his phone show it opening and closing.  They cleaned it up and now it works like a champ.  

There was also much discussion about what the maximum boost should be.  Apparently it is documented a different values in different documents.  39.9, 40, 41, 42.   Lockwood stated that they were comfortable with it at 41 and it will shut itself off at 47 but we could never get anything in writing.

So now, I'm seeing 40.3 and am happy with that.  She takes off and climbs like crazy fully loaded.


David 

[MarkGregor]

David,

Ive always been told it is supposed to be set 40 inches but not to be concerned unless it gets above 41.5.

A cable adjustment usually fixes a low manifold pressure problem but obviously did not for you.

Some pilots like to pull back to 35 inches after they are off the runway. These seem to be the ones who are most likely to have a sticky or gunked up turbo. Leaving it at 40 inch setting till you are at least pattern altitude helps keep the wastegate "exercised" and the turbo will stay cleaner. Running your engine regularly at low power settings can carbon up your engine and turbo also. I suggest running your engine at higher power settings and/or RPMs regularly.

Davids plane was indicating low manifold pressure when we delivered it to him so it was likely already gunked up when he got it. We should have had the problem taken care of before delivery but our service center didn't have time to look at it quickly and David was ready to get going.  I suggested he have the cable adjusted when he got it back home. Obviously this time it was a little more involved that the cable adjustment.

Mark