New to me M20K - many questions (now AOG)

[anonymouse]

Well things took an interesting turn today.

The mechanic did the fuel setup yesterday, and on takeoff I had exactly the same fuel flow - 21 GPH - as before. A subsequent phone call would reveal that he set it up at 40", despite me bringing him the manual and saying it had to be adjusted down to 24.7GPH at 37"  because of the intercooler. "Oh" he said.

What's even more fun is that I called him from SBD, where I'm now AOG. On climbout from the LA area towards Denver at 10,000 feet, I had a sudden loss of about 15" of MP and 12 GPH fuel flow. I immediately diverted and landed normally (with next to no engine power, but with oil pressure/temperature normal). I was showing something like 4 GPH on final. My working theory is that whatever he 'adjusted' popped off and slipped resulting in the sudden power loss. There is no sign of oil/leaks/catastrophic failure/untoward sounds. I don't think I lost my turbo because the severe power reduction was at all altitudes.

I have a mechanic from CCB coming out on Friday to diagnose the problem. I didn't have time to look at anything on the ramp as I have a series of business meetings tomorrow and had to make immediate commercial flights.

[kortopates]

Well things took an interesting turn today.

The mechanic did the fuel setup yesterday, and on takeoff I had exactly the same fuel flow - 21 GPH - as before. A subsequent phone call would reveal that he set it up at 40", despite me bringing him the manual and saying it had to be adjusted down to 24.7GPH at 37"  because of the intercooler. "Oh" he said.

What's even more fun is that I called him from SBD, where I'm now AOG. On climbout from the LA area towards Denver at 10,000 feet, I had a sudden loss of about 15" of MP and 12 GPH fuel flow. I immediately diverted and landed normally (with next to no engine power, but with oil pressure/temperature normal). I was showing something like 4 GPH on final. My working theory is that whatever he 'adjusted' popped off and slipped resulting in the sudden power loss. There is no sign of oil/leaks/catastrophic failure/untoward sounds. I don't think I lost my turbo because the severe power reduction was at all altitudes.

I have a mechanic from CCB coming out on Friday to diagnose the problem. I didn't have time to look at anything on the ramp as I have a series of business meetings tomorrow and had to make immediate commercial flights.

Sorry to hear that, but there is nothing to pop off from setting the screw on the metered fuel pressure adjustment, nor the idle or idle mixture. Your engine analyzer downloaded data may shed some light on the issue.

 

I highly encourage folks getting their redline limits set properly to do a trip in the pattern before departing home. You really can’t get it perfect on the ground and it’ll change a bit in the air. Yours is simpler since it only has a fixed or at most manual waste gate, but still it often takes some tuning to get right.

 

Also it’s usually best to set your max FF to from 0.5 to 1.0 GPH above CMIs high number (which where turbo Plus got it); while of course at your 100% MAP (~37”). You want TIT below 1400F and preferably near 1300F at full power. I often see them way to high.

 

 

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[anonymouse]

I don't have a way to download data, yet. I have a jpi 700.

He also changed the oil and re rigged the flaps, but I don't see either causing the problem either. I guess I'll find out on Friday.

[kortopates]

I don't have a way to download data, yet. I have a jpi 700.
He also changed the oil and re rigged the flaps, but I don't see either causing the problem either. I guess I'll find out on Friday.

Always possible something got loosened or removed to give access to something else. But your describing a massive induction leak which could come from many things including a loose induction coupling hose, pop off valve etc but hopefully not the turbo going out. They usually give signs first from excessive oil loss.


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[Bob]

Yes, as Kortoplates stated, adjust fuel flow higher than 24.7 gph at full power.  My regular number is 25.5-25.7.  That will allow you the extra fuel to climb while keeping CHT's low. If you are in the 24.5 range or lower, your climb will be below 1000 to keep temps down.  If it is set 26.2 or higher, you will struggle to get the other adjustments set and will also have a negative effect on smoothness, idle and how it starts.

Some of the first steps to doing the SID97 injection setup include flushing the fuel system, checking for exhaust and induction leaks.

I have a feeling that the AP may have forgotten to tighten the clamps sealing the induction tube that exits the turbo.   It may have then popped off and you lost boost.

If this is the case, the injection was set up with a induction leak that was caused by putting everything together after checking for induction leaks.  My brain hurts! Any suggestions to reword this are appreciated.  The bottom line is if that pipe came off, the injection MUST be completely setup again, since all adjustments are off!

[gsxrpilot]

I'm very thankful to be on a field with a proper Mooney Service Center. And not one that's in name only. JD and Laura at SWTA really know their Mooneys and always have a shop full of them. 

It makes a difference.

[jlunseth]

 That experience, where you give the mechanic the STC and they use the straight up SID97 method, is fairly typical.  I have had to go around on that with some mechanics three times before they get it right.  And I agree with the idea of setting the max fuel flow a little richer than the factory setting.  You can always use the red knob to lower it, but once the mechanic sets an upper limit you are stuck with that.  The only issue with a richer setting is that it often also means a richer setting at idle.  There again, you have the red knob, you can use it.  The one thing I notice at idle is that the engine will “burble” on final if its overrich.  I lean mine way out on final so that goes away.  You have to add some fuel (push in the red knob) during the landing roll out because the prop is no longer being helped by your airspeed and the engine can try to quit.  That’s on the ground.  It does not do that in the air.

[jackn]

13 minutes ago, jlunseth said:

 That experience, where you give the mechanic the STC and they use the straight up SID97 method, is fairly typical.  I have had to go around on that with some mechanics three times before they get it right.  And I agree with the idea of setting the max fuel flow a little richer than the factory setting.  You can always use the red knob to lower it, but once the mechanic sets an upper limit you are stuck with that.  The only issue with a richer setting is that it often also means a richer setting at idle.  There again, you have the red knob, you can use it.  The one thing I notice at idle is that the engine will “burble” on final if its overrich.  I lean mine way out on final so that goes away.  You have to add some fuel (push in the red knob) during the landing roll out because the prop is no longer being helped by your airspeed and the engine can try to quit.  That’s on the ground.  It does not do that in the air.

This sounds about right. SID97 also states that you can set fuel flow 5% higher than the max FF in order to do partial power climbs. This is what I do. If I’m not in a hurry, I’ll reduce my MP to 32” 2600 rpm at 18.5 gph. I’ll lose about 200 f/min but FF drops from 25 to 18.5. A side benefit of setting the FF higher is that on a hot/ humid day, I’ll still get plenty of fuel flow t keep everything cool. On a cold day, just use the red knob. 

 

[kortopates]

3 hours ago, jlunseth said:

 That experience, where you give the mechanic the STC and they use the straight up SID97 method, is fairly typical.  I have had to go around on that with some mechanics three times before they get it right.  And I agree with the idea of setting the max fuel flow a little richer than the factory setting.  You can always use the red knob to lower it, but once the mechanic sets an upper limit you are stuck with that.  The only issue with a richer setting is that it often also means a richer setting at idle.  There again, you have the red knob, you can use it.  The one thing I notice at idle is that the engine will “burble” on final if its overrich.  I lean mine way out on final so that goes away.  You have to add some fuel (push in the red knob) during the landing roll out because the prop is no longer being helped by your airspeed and the engine can try to quit.  That’s on the ground.  It does not do that in the air.

We might have talked about this before. But a higher max fuel flow does not need to accompany a richer idle. Their are two separate adjustments, entirely independent of the max FF, used to set up the idle and there is nothing at all that would prevent for example an overly lean Idle mixture with an excessively high max FF. But what is critical is that once the max FF is set up (metered fuel pressure) that then the tech needs to go back and test and perhaps re-adjust the low pressure idle unmetered fuel pressure and possible the idle mixture adjustment - which is likely why yours might be overly rich. Can't just set one without re-checking the others.

Many comment about setting their max FF significantly above spec. As posted before, a relatively small amount like 0.5 to 1 GPH or even 5% higher as Jack @jackn cites above is good, but recognize you're preventing your engine from making full rated power as you keep increasing the FF. Thus be very careful about going higher and do so only when EGTs/TIT's indicate the mixture is too lean. 

[TargetDriver]

On ‎3‎/‎5‎/‎2018 at 9:57 AM, gsxrpilot said:

 

Better yet, get in that 231 and fly it to Ada, OK to attend a weekend APS seminar at GAMI. You can also get JeanPaul from GAMi to go up with you in your 231 and see first hand what's going on.  Unless the value of that TSIO360 engine is just pocket change for you, I'd want to know how to fly it as to get the most hours of service out of it. 

Paul, I just caught a very useful bit of future advice from you. Thanks !  I'm most likely relocating from NorCal to OKC in 3-5 months. I didn't know that I could get that kind of knowledge and assistance from the GAMI folks there.  I've been away from my K for almost a year now being deployed but that ends in 2 weeks !  Like Anonymouse, I feel comfortable and safe flying my K but there's a lot of knowledge gaps I could stand to fill on its operation. Other than a few returning-to-home base just after dark, I've kept all my flights below 14.5K and in relatively good conditions.  I'll definitely look them up for GAMI's and a GAMI seminar when I get settled.  Sorry guys, didn't mean to get off thread track but I am very interested in most of the questions/responses too...except I don't have the intercooler.

[Utah_Pilot]

53 minutes ago, TargetDriver said:

Paul, I just caught a very useful bit of future advice from you. Thanks !  I'm most likely relocating from NorCal to OKC in 3-5 months. I didn't know that I could get that kind of knowledge and assistance from the GAMI folks there.  I've been away from my K for almost a year now being deployed but that ends in 2 weeks !  Like Anonymouse, I feel comfortable and safe flying my K but there's a lot of knowledge gaps I could stand to fill on its operation. Other than a few returning-to-home base just after dark, I've kept all my flights below 14.5K and in relatively good conditions.  I'll definitely look them up for GAMI's and a GAMI seminar when I get settled.  Sorry guys, didn't mean to get off thread track but I am very interested in most of the questions/responses too...except I don't have the intercooler.

Safe return Brother.  Too bad Pete's in Manas Isn't around anymore.

[jlunseth]

10 hours ago, kortopates said:

We might have talked about this before. But a higher max fuel flow does not need to accompany a richer idle. Their are two separate adjustments, entirely independent of the max FF, used to set up the idle and there is nothing at all that would prevent for example an overly lean Idle mixture with an excessively high max FF. But what is critical is that once the max FF is set up (metered fuel pressure) that then the tech needs to go back and test and perhaps re-adjust the low pressure idle unmetered fuel pressure and possible the idle mixture adjustment - which is likely why yours might be overly rich. Can't just set one without re-checking the others.

I think we have and you are right the two are separate.  The frustration I ran into is that when I finally get a mechanic to set the high flow right, then the idle flow is off.  You said it better than me, they have to go back and check that and it often doesn’t seem to get done.

[carusoam]

Losing 15” of MAP sounds like a hose clamp came loose/off...

JPI 700 series has the ability to download data using a cable to a computer using a USB port.  JPI has the software and the hardware bits available on their site...

Are you able to take the cowl off where you are?  Not suggesting to make repairs, but as for finding out what came loose...

Are you skilled with mechanical devices?

Early on, I asked if you had any transition training... this wasn’t to poke fun at you.  It was more in line with learning all systems with somebody that knows how they are supposed to be working...

When systems aren’t set up properly anymore, a Mooney specific CFI will be able to tell you what he is or isn’t seeing...

Starting to sound like to many new to you experiences, Too quickly...

Were you using a GA plane to make this work flight prior to using the M20K?

A new to you plane...

A fully complex M20K that isn’t ready for prime time...

SO many questions that no human being could answer in a single seating...

Makes being OAG sound like a lucky experience...

Did you get a PPI done on the plane, or is this too much to ask without sounding mean? (Devin wright, Danbury, CT)

I’m hoping you can get this set up properly prior to the next launch.  There is too much at risk to do any other way...

Take no short cuts. Don’t skip any steps.

ask more questions... just separate them out so you can refer back to them later.

Are you staying Anonymouse for a reason?  

Private pilot thoughts only, thoughts of sitting out...

Best regards,

-a-

[anonymouse]

Thanks for the thoughts, @carusoam. I feel like I've gotten some great support in this thread and in a couple PM's with people reaching out to answer most of my questions, and I think getting the fuel flow set up properly with an A&P capable of reading an 8 page document and listening to my verbal instructions will go a long way to solving a good chunk of my initial issues.

I've since found where the valves are to adjust the oxygen flow, so that's one topic off the plate as well.

I had to take a commercial flight and won't be home for a few days. The (new) mechanic (at a Mooney Service Center) is going to look at it early next week. As others have said, it's likely a blown off intake hose. I got a thorough PPI - I think my home field mechanic just F'ed things up.

I have about 1300 hours TT, am instrument current, and previously flew a Columbia 350 on the same work trips. I don't feel like I'm in over my head at all - I just have a bad mechanic.

[carusoam]

I’ve lost a couple of Mooney friends over the years... I’m overly cautious (self serving) when letting anything slide by...

I just don’t have the skill to be gentle when asking probing questions... 

Which MSC is it at now?

Best regards,

-a-

[anonymouse]

As most predicted, it was the hose backing off the induction port of the turbo with just a small opening. So, I'm back and flying again. Now for attempt #2 of fuel flow setup.

[jlunseth]

On a side note, it is time for my annual.  My MSC changed hands last year, so I am going to have to go through the dreaded "fuel flow setting" dance. They did it right last year, so hopefully they get it right this time. 

[N231BN]

On a side note, it is time for my annual.  My MSC changed hands last year, so I am going to have to go through the dreaded "fuel flow setting" dance. They did it right last year, so hopefully they get it right this time. 

Is it required at every annual?

[kortopates]

Is it required at every annual?

CMI recommends checking it at annual and it’s in the Mooney annual checklist but no adjustment needed as long as it stays in spec.


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[Bob]

On 3/8/2018 at 7:39 AM, jackn said:

This sounds about right. SID97 also states that you can set fuel flow 5% higher than the max FF in order to do partial power climbs. This is what I do. If I’m not in a hurry, I’ll reduce my MP to 32” 2600 rpm at 18.5 gph. I’ll lose about 200 f/min but FF drops from 25 to 18.5. A side benefit of setting the FF higher is that on a hot/ humid day, I’ll still get plenty of fuel flow t keep everything cool. On a cold day, just use the red knob. 

 

The 5% higher  is only for engines with a fuel pressure regulator.  I am not sure about the 252, but the 231 does not have one.

3) Turn the regulator adjustment screw clockwise to increase or counterclockwise to decrease metered fuel pressure and fuel flow. On turbocharged engines equipped with a fuel pressure regulator, the FULL POWER metered fuel pressure and fuel flow must be adjusted to five (5) percent higher than the maximum specified limit when regulator is disconnected. This is required to ensure adequate part-throttle fuel flow.