PA46 strange engine behaviour

TallyTwo

Filing Flight Plan
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Jul 13, 2018
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MJS
Hi all,

I regularly fly a PA46-310P. Had the engine overhauled and everything has been fine until the last few flights.

I have experienced the engine coughing twice. Once during take off, engine params were good (temperatures, etc...) it was less than two seconds and suddenly recovered.

The second time, I was climbing through FL190 when the roughness appeared again but this time it lasted around 10 secs with a small power loss. It recovered. I used the rest of the flight the aux pump in LO.
I don't it was caused by vapor lock because it was almost an ISA day, clear of clouds.

Once I landed, I had the engine and the fuel pump checked. Nothing abnormal was found.

Any thoughts? Thanks.
 
What kind of engine monitoring do you have? Can you copy the engine file to upload? What altitude was your takeoff runway and was the oil warm? Were you LOP or ROP in the climb?
 
Hi Jeff, thanks for you reply.

The monitor is an EDM-800 so unfortunately no data log.
The t/o was at SL. The oil was within green arc. Slightly on the low side but green. During the climb, the mix was full rich.
 
It’s hiccups like these that unless it’s a total fail of some kind, is hard to replicate and/or diagnose. My suggestion would be to have a local A&P tag along with you on an upcoming flight.
 
Was it "too rich" maybe? What kind of fuel flow were you seeing?

My experience is was from an SR22T and TN and at the higher altitudes (even though turbo and all that) the plane felt very sensitive to fuel flow fluctuations. Fuel pump was pretty much always needed for vapor lock issues and the engine would occasionally sound funny and you've have to finagle the fuel flow. Full rich the whole way up

But what the hell do I know. Sucks to hear your engine cough
 
Was it "too rich" maybe? What kind of fuel flow were you seeing?

My experience is was from an SR22T and TN and at the higher altitudes (even though turbo and all that) the plane felt very sensitive to fuel flow fluctuations. Fuel pump was pretty much always needed for vapor lock issues and the engine would occasionally sound funny and you've have to finagle the fuel flow. Full rich the whole way up

But what the hell do I know. Sucks to hear your engine cough
The mixture was full rich during the cruise climb as per POH. I didn't see any FF fluctuations. The vapor lock was the first thing I suspected.
The manual allow the use of the pump in LO so I guess I will use it during the next take offs until I gain confidence again.
 
Sticky valve? Had one in a Warrior that was intermittent like that.
 
Can't be 100% sure but I do my test and the fuel station is owned and serviced by a company so I assume they test it too.
Never assume... the FBO here supposedly tests their fuel everyday, but @Bill Jennings still found a considerable amount of water in his tanks.
 
I teach in the Malibu quite a bit (both the Continental and Lycoming versions, though the Continental is much preferred!) as well as in the Cirrus models. I've had exactly what you describe before in the Cirrus on climbs (even had it during TO once and aborted, but nothing abnormal). A quick 2 second period where there was a "cough" and a brief vibration, but then everything returned to normal. I thought it was FF related too, meaning the engine was getting to much fuel and it was flooding a bit, but finally asked a mechanic about it. He said he had seen that before in a 421 engine and it was a timing problem, which would make sense with your new engine. He said check the mag timing, make sure a P lead isn't inadvertently grounding out, and check the ignition switch too. Those all were possible issues.

Hank Gibson
Texas Top Aviation
512-270-1298
 
Hi Jeff, thanks for you reply.

The monitor is an EDM-800 so unfortunately no data log.
The t/o was at SL. The oil was within green arc. Slightly on the low side but green. During the climb, the mix was full rich.
My 800 records data...

Paul
 
If I climb too steep on a hot day my 550 will do it too. In my case it’s vapor lock. As long as I keep my speed above 140 kts in the climb it doesn’t do it. Less and it will start to surge and has even briefly cutoff once. Turning in the fuel pump usually resolves it.
 
Full rich at 19,0000 feet?
 
Full rich at 19,0000 feet?

Don't know what the critical altitude is for the Continental powered Malibu (17,000 ft?), but would assume you would want full rich mixture to at least that point in the climb.
 
Full rich at 19,0000 feet?

Yes.
The POH states fuel rich during the climb and also, in the leaning limitations, it states that mixture must be full rich during RPM higher than 2400 and MP above 31 inHg (75% power).
 
The Conti powered PA46 is way different from the Lyc powered PA46s. I lean to 32 GPH in climb in my Lyc powered PA46 once I get above 1000-1200 AGL.

To the OP, have you asked this question on MMOPA? Great resource. Centuries of experience over there...
 
The Conti powered PA46 is way different from the Lyc powered PA46s. I lean to 32 GPH in climb in my Lyc powered PA46 once I get above 1000-1200 AGL.

To the OP, have you asked this question on MMOPA? Great resource. Centuries of experience over there...
Thanks for your reply.

No, I haven't. Do you know if is there any kind of memebership trial?
 
The monitor is an EDM-800 so unfortunately no data log.
You may want to look into that. The EDM-800 has data recording capability. Different options exist for accessing the recorded data. Mine had a round plug in the panel which required JPI's USB download box. You may still be able to get to what was recorded on that flight.

- Martin
 
No idea but if you are a PA46 owner or operator, the membership will be one of the best aviation deals you will get...
Having consultative access to Kevin Mead alone is worth the price of admission.

Thanks for your reply.

No, I haven't. Do you know if is there any kind of memebership trial?
 
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