Momentary Loss of Power When Levelling Out

[gbarkman]

I own a 1983 M20K that had the turbo conversion done on it to essentially make it an M20T.  Since purchasing it 4 years ago the plane has flown roughly 400 hours and apart from losing a magneto in flight (not a fun experience), it has flown almost flawlessly with one ongoing and notable exception.  On virtually every climb just after levelling out, the engine seems to momentarily lose power, as if there was a fuel pump blockage or water in the gas.  Before every flight we are careful to always check water in the fuel cells and pull the fuel discharge lever on the floor so water is not the issue.

After a momentary loss of power, everything seems to come back normal and the problem does not seem to persist.  It is unnerving though, particularly in heavy IMC.

Anyone else out there experience anything similar?  Any ideas on what it could be?

[takair]

A little out of my comfort zone, but have you tried leveling off with electric pump on?  Does it change with degree of level off? (G load)

[carusoam]

GB,

You have brought forth something that sounds very unusual for any Mooney...

Do you have an engine monitor or fuel flow data to go with your description?

Does the MP drop off?

Does the rpm change?

Does the FF Change?

do you get a sound change with that?

Often people post graphs of their JPI data for a flight where the weirdness occurred.  We have some people that are very familiar with these things and don't mind sharing what they know...

We also have a bunch POH of K pilots that are really familia Pr with this plane and may have some input for you...

Try to fill in your avatar data. It helps people get to know who you are and where you are to better help you out.

Best regards,

-a-

[gbarkman]

Thx for the feedback takair and carusoam.  I will plan to spend a bit more time in the practice area over the next few weeks and try different options and graph some better data to share back.....appreciate it.......grant

[carusoam]

Grant,

Can you give us some additional information about the power plant you have?

Some Ks have been repowered by Rocket Engineering Using a TSIO520 with an intercooler and pressure controller to match...

Or do you really have a TN'd IO550 in your K? The Acclaim's powerplant.

What altitude are you leveling off at?

With the extra details We'll draw some collective ideas from the MooneySpace community.

The more details you can give the better the responses usually are...

Sounds like you may be describing the change in attitude results in a change in prop blade angle while the engine maintains rpm under the different load. A whole bunch of things are working at that point to maintain equilibrium... something may not be working as expected... 

Keep in mind, I’m only a private pilot, not a mechanic...

Best regards,

-a-

[jlunseth]

I am confused.  An M20 K is an M20T.  “M20T” is the aircraft type designation used in a flight plan, and tells ATC the aircraft is a turbocharged M20.  A little unusual in that the “T” designation is typically for turbine engines, but this is how it works.  The K is a turbo already, so there would be no need for a turbo conversion.  Must be an F or J with a turbo on it, that the modder labeled a K of some kind, but it is not a true K.  If a turbonormalized J, that is a Lyc engine not the Conti that is in a K.  

The electric pump is not used for any normal regime of flight in the Conti powered K.  That would result in an overrich condition.  If you are using the electric pump for any reason, stop using it.  The pump is only used in the event of failure of the mechanical pump, and I use it just a little for starting, but that is it.  It should be in your takeoff checklist to verify that the pumps are OFF.   If this is truly a K with the Continental engine, don’t use the pump.  I don’t know what the deal would be if it is a turbonormalized Lyc J.  

The question I have is what do you do when you level off?  You should do nothing with the engine controls, just level the aircraft.  My procedure is to climb full rich full power, which is about 35-36 inches MP in my K231.  It is different in the K252 because it has a distinctly different wastegate controller, I believe you just firewall the throttle and let the 252 controller handle the rest, but don’t quote me on that I don’t fly a 252.  You do not lean the engine out for climb.  At the top of climb, simply pitch the nose down to level flight, no touching the controls.  Close the cowl flaps and let the aircraft speed up on its own to at least cruise speed. I assume the gear and flaps are up, they should be retracted on takeoff when you reach a positive rate of climb. I while the time away by setting the ASI for altitude and OAT.  Once the aircraft has reached cruise speed (you are still at full rich, full power), then you reduce the RPMs and lean the engine for cruise to whatever your cruise setting is going to be.  

This is the recipe for the true K.  If you have some kind of turbo conversion, yours is not a K.  I would still use this procedure, but not knowing the engine, I can’t say whether electric pump would be used or not.

Could be a Rocket I guess.

Edited January 8, 2018 by jlunseth

[gbarkman]

Thx for the further input.  I will verify but I understood the powerplant is the TSIO520 from Rocket.  You are correct jlunseth, we file as an M20T but it is a K model in all the tech logs.  As you indicated, we climb firewalled and don't change settings until reaching altitude.  The altitude we climb to varies on the mission, the momentary loss of power doesn't seem to be dependent on where we level off, it has occurred anywhere from 6K up to 18K.

As noted in my previous reply, my pilot partner and I will plan to put in some time in the local practice area to see what stats we can gather from the engine analyzer, MP, RPM and FF and re-post.

[N201MKTurbo]

The Rocket that I've been fooling around with lately was having similar problems. It would stumble when you reduced throttle. Readjusting the fuel flows on the fuel injection system cured the problem.

[Bob - S50]

How do you know it is losing power?

Does it get very quiet for a second and then get loud again?

Does the plane decelerate?

What are you sensing that tells you that you've lost power?

[jlunseth]

15 minutes ago, gbarkman said:

Thx for the further input.  I will verify but I understood the powerplant is the TSIO520 from Rocket.  You are correct jlunseth, we file as an M20T but it is a K model in all the tech logs.  As you indicated, we climb firewalled and don't change settings until reaching altitude.  The altitude we climb to varies on the mission, the momentary loss of power doesn't seem to be dependent on where we level off, it has occurred anywhere from 6K up to 18K.

As noted in my previous reply, my pilot partner and I will plan to put in some time in the local practice area to see what stats we can gather from the engine analyzer, MP, RPM and FF and re-post.

Yes, that is a K with a non-factory engine hung on it.  We have turbo’d F and J owners, K231 and K252 owner, and Rocket owners on the site.  Just trying to figure out who you needed to talk to and it looks like you have someone knowledgeable.  The only other question I have though, is exactly what is happening when the engine stumbles?  Does it happen when the aircraft is pitched down into level flight with no other changes, or does it happen after the aircraft has been pitched over when you throttle the engine back to make your cruise setting?

[RobertGary1]

We might be confusing two different things. The FAA Flight Plan designation of "M20P" and "M20T" do not refer to Mooney models but rather simply designated if the plane is turbo equipped or not so ATC knows what altitudes can be assigned. There are only 2 M20 designations that exist for fligtht plans "M20P" for all non-turbo M20's and "M20T" for all turbo Mooneys. Not to be confused with actual Mooney model designation.

 

-Robert

[gbarkman]

Just FYI, I spoke with our tech this morning.  For the record, here are his comments.

 

"Your plane is an M20K. There were two models, the earlier 231 model and the later 252 model. They both use the Continental TSIO360 engine.  The 231 used the LB variant of this engine which had a smaller turbo and intercooler and a poorly designed intake manifold. The problem with this setup was that it was prone to overheat and subsequent premature engine overhaul, problems that were mostly fixed on the 252 model and it's upgraded MB engine variant."  

 

So our plane started life as an M20K 231 model and was converted in the 90's by a company in Florida with an approved "262 Trophy" conversion which made it for all intents and purposes a 252, the only real difference is that the real 252 has a 24 volt system, ours still has the 12 v. All that being said, for the purposes of this forum, it would be fair to say our plane is an '83 M20K with the 262 Trophy mod.

 

As for the engine analyzer trend info ours is an early model JPI EDM 700 which has an ability to download engine trend info. We understand it's not that user friendly in the acquisition of the data but we are going to try to recreate the issue and capture engine data with a laptop and a serial port. 

[mike_elliott]

Then you dont have the TSIO 520 engine if it is a 262 Trophy conversion, you have the TSI0360. In any event, get with someone who has the correct gauges, knows what they are doing and have the fuel metering system set up correctly per the Continental SB. That will probably cure your issue.

[gsxrpilot]

There sure are a lot of variations on the K. Step one, know what you're flying.

231 - GB
231 - LB
231 - LB - upgraded to 262 Trophy
231 - Rocket 
252 - MB
252 - SB - upgraded to Encore
Encore - SB
 

[carusoam]

The JPI 700 series is an older, but very powerful data collector.

Depending on What is connected to it and how it is set-up, it can be even more powerful.

If Power is being lost while data is being collected.  The JPI will have some traces of regarding what and when something happened.

We also have an MSer that has a lot of experience with interpreting JPI data...

See if Paul / @kortopates may have some input for you.  Some services are actually free and are very worth trying out...

It would be great if you’re FF data is being recorded with your CHT, EGT and TIT data...

Downloading data from the old JPI may require acquiring an interface device.  Not very expensive computer serial cable thing with USB plug for any portable computer...  check the JPI website on What is needed.

By the sound of it, You May have collected enough data already to make some known maintenance next steps...

The Trophy 262 conversion is a pretty well respected plane.  The guy that ran the business back in the day could have done things differently from a business point of view.  Separate issue from the planes they modified.

PP thoughts only, not a mechanic or aviation engineer...

Best regards,

-a-

https://www.jpinstruments.com/shop/edm-700/?gclid=Cj0KCQiAyszSBRDJARIsAHAqQ4o3VZvkYTpNjnpDWSOdeLOq-HI6wJ8cS2ZQX1hRQCAbRidqlNvYZewaAsoPEALw_wcB

[jlunseth]

27 minutes ago, gsxrpilot said:

There sure are a lot of variations on the K. Step one, know what you're flying.

231 - GB
231 - LB
231 - LB - upgraded to 262 Trophy
231 - Rocket 
252 - MB
252 - SB - upgraded to Encore
Encore - SB
 

And a 261, one of the posters here, Bennett, had one at one time.  So its the TSIO360 engine, probably the MB.  At any rate, we can say that boost pumps should be off in normal flight, and if this is happening when the OP throttles back to cruise, then I agree with Mike, the fuel metering system needs to be checked.  I have seen stumbling when the engine is leaned out too far and then the pilot attempts to power it up (increase throttle), but only on the ground, never in the air, and that is the opposite of what the OP seems to be doing, he is powering back.

[Piloto]

G Barkman

You may still have water in the tank after you drained. Remove the drain valve and check for water. If the drain holes on the adapter plate are plugged the valve is just draining from the top of the stem. This leaves about 1 1/2 inches water not drained.

José 

[kortopates]

Before you try to collect data on the JPI, update the default data sampling rate from once every 6 sec to its fastest rate which is every 1 or 2 sec. Hold both buttons down to go into programming mode and then use the Step key to step to the data sampling rate. Once every 6 sec won't provide much detail.

If the older EDM 700 unit hasn't been upgraded to have USB memory interface you'll have to find a serial cable and PC with a serial port which is impossible these days so perhaps a serial to USB converter - I do know if those are available so not sure how you'll get the data downloaded. 

But if you can get the data, create a free account on SavvyAviation.com to upload and analyze the data. It has very easy to use tools which are easier to work with than JPI's Eztrend s/w plus you can share the data with your A&P or anyone. 

If you do the test flight, be sure not to reduce power after first leveling off - wait a minute or two first, so you can separate the leveling off event from the power reduction event. Hopefully your analyzer has FF in addition to EGT & CHT and preferably MAP and RPM as well or you'll want to upgrade the unit soonest.

If you think there was any chance it had water in the fuel or is parked outside and the cap o-rings show cracking, you should probably just add some dry isopropyl alcohol now to dissolve any trapped water and eliminate it from the possibilities. its an approved additive for this purpose and can only help.

[carusoam]

JPI used to have the serial to USB adapter on their site... for convenience.

They still list the wire and serial connector if needed...

 

Best regards,

-a-

[jaylw314]

13 hours ago, carusoam said:

JPI used to have the serial to USB adapter on their site... for convenience.

They still list the wire and serial connector if needed...

 

Best regards,

-a-

This USB-to-Serial converter is the one I use for my JPI EDM-711 (same as the 700).  The EDM-700 should have come with the serial cable if it had the port installed, that you might have to order from JPI if you don't have it (thankfully, the previous owner for my plane buried it in the little box of goodies he left in the plane)...

[carusoam]

Using the smile.amazon. does the same amazon thing AND supports the MooneySummit... 

https://smile.amazon.com/gp/product/B0000VYJRY/ref=smi_www_rco2_go_smi_2609328962?_encoding=UTF8&ie=UTF8&psc=1

Thanks Jay. That looks a lot like the converter I have for my JPI as well.

Best regards,

-a-

[jaylw314]

23 hours ago, carusoam said:

Using the smile.amazon. does the same amazon thing AND supports the MooneySummit... 

https://smile.amazon.com/gp/product/B0000VYJRY/ref=smi_www_rco2_go_smi_2609328962?_encoding=UTF8&ie=UTF8&psc=1

Thanks Jay. That looks a lot like the converter I have for my JPI as well.

Best regards,

-a-

Ha, never heard of amazon smile before...

[carusoam]

^^^ Let’s see if I can get @mike_elliott to point us towards the Amazon smile thread.

Briefly... it supports a program that supports downed Mooney pilots and the people that may be affected by the loss.

Best regards,

-a-

[kortopates]

Just now, carusoam said:

^^^ Let’s see if I can get @mike_elliott to point us towards the Amazon smile thread.

Briefly... it supports a program that supports downed Mooney pilots and the people that may be affected by the loss.

Best regards,

-a-

Smile.amazon.com doesn't automatically go to the Mooney Summit. One has to select which charity to give too among literally hundreds. For details go to the FAQ at: https://smile.amazon.com/gp/chpf/about/ref=smi_aas_redirect?ie=UTF8&ref_=smi_se_ft_abt_saas