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Left mag check kills engine


WaynePierce

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31 minutes ago, carusoam said:

1) Log check... hours in each mag...

2) 500 hours since last service on the bad mag? Send out to Aaron...

This gets you going the right direction without spending much time proving something has experienced normal wear...

3) Most likely you have a lot more hours than 500... only your log knows.

4) if the maintenance is done recently, how old is the ignition switch? 5,000 hours?

5) switches are rebuildsble...

6) what kills the engine is grounding of the mag... broken ground wires keep the plane running...

7) Start studying details regarding new mags and timing. A few details you want to be knowledgeable on...

8) Do you have a monitor?  Homework assignment... download the flight detail when the mag quit and post it.

Keep asking questions, no flying until you know your next steps...

Best regards,

-a-

Great advice and will begin the learning process as soon as I get home. I may have to buy the usb box from JP Instruments ... I think I have the cable in box with all the logs.

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Not intending to hijack this thread, but here's a little teaser (happened to me, after annual).

I have an Lyc A3B6 201.

On run-up or for that matter at any rpm - engine runs fine on BOTH mags. On LEFT mag it runs fine as well (with requisite RPM drop). On switching to RIGHT mag - EGT on cyl 2 and 4 drop immediately, engine runs rough on idle and backfires if RPM increased. Cyl 1 & 3 run normally albeit slight RPM drop. What's the issue? Mags were fine before annual.

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40 minutes ago, wishboneash said:

Not intending to hijack this thread, but here's a little teaser (happened to me, after annual).

I have an Lyc A3B6 201.

On run-up or for that matter at any rpm - engine runs fine on BOTH mags. On LEFT mag it runs fine as well (with requisite RPM drop). On switching to RIGHT mag - EGT on cyl 2 and 4 drop immediately, engine runs rough on idle and backfires if RPM increased. Cyl 1 & 3 run normally albeit slight RPM drop. What's the issue? Mags were fine before annual.

Crossed wires on cylinders 2&4?

Clarence

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Not only is the Doc good at normal psychology of the Mooney engine...

He is really good at the abnormal psychology as well...

Diagnosing a mis-wired magneto, from a few sentences regarding its operation and engine monitor details!

Dang, you’re good Doc! A real Pro!

Thanks for sharing your experience.

that one had me stumped...

Fortunately, the simple challenge didn’t cause firing BTDC by too much... 

Best regards,

-a-

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On 10/30/2018 at 3:14 PM, carusoam said:

1) Log check... hours in each mag...

2) 500 hours since last service on the bad mag? Send out to Aaron...

This gets you going the right direction without spending much time proving something has experienced normal wear...

3) Most likely you have a lot more hours than 500... only your log knows.

4) if the maintenance is done recently, how old is the ignition switch? 5,000 hours?

5) switches are rebuildsble...

6) what kills the engine is grounding of the mag... broken ground wires keep the plane running...

7) Start studying details regarding new mags and timing. A few details you want to be knowledgeable on...

8) Do you have a monitor?  Homework assignment... download the flight detail when the mag quit and post it.

Keep asking questions, no flying until you know your next steps...

Best regards,

-a-

After researching the engine log, the mag was rebuilt at the same time the engine was OH'd at 1325.2 last annual (September 12, 2018) there was 308.1 TSMOH. When I parked it last time the tach read 1680.5 so 355.3 on the rebuilt Mag. So probably time to have the mag rebuilt again.

I haven't found anything in the logs about the switch being rebuilt or replaced so I can assume 1680 hours on the switch.

I've downloaded the log data from the JPI 800 but I don't really know what to do with that information. I can see a drastic dip in rpm when I was doing the run-up In the simulator mode, which confirms what I was seeing in person. How can I show you information from the data pull? By the way, the USB box they sell for downloading works like a charm!

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After researching the engine log, the mag was rebuilt at the same time the engine was OH'd at 1325.2 last annual (September 12, 2018) there was 308.1 TSMOH. When I parked it last time the tach read 1680.5 so 355.3 on the rebuilt Mag. So probably time to have the mag rebuilt again.
I haven't found anything in the logs about the switch being rebuilt or replaced so I can assume 1680 hours on the switch.
I've downloaded the log data from the JPI 800 but I don't really know what to do with that information. I can see a drastic dip in rpm when I was doing the run-up In the simulator mode, which confirms what I was seeing in person. How can I show you information from the data pull? By the way, the USB box they sell for downloading works like a charm!

Savvyanalysis.com allows you to upload, from which you share.
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Thank you, I’ll look in to it and share. 

I had a bad weekend that I’ve learned a lot from. I went to the hangar and taped off where the tires shoul be to avoid hangar loss, I took the top cowling off to take a good look at the mag(s) and downloaded the information from the JPI. A good noob first time owner experience, but I LOVE this plane it flies so well, and fast, I really enjoy the opportunity to take her and my wife on trips. 

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Rough numbers...

Building a time line regarding your plane is a brilliant idea.  You get to learn a lot about it’s history...

1985 J

1600hrs TT

MOH at 1325hrs

300 hrs on the mags?  They have paperwork that says who did the OH on the mags?

Nothing stands out as an anomaly... but, I would be looking for details that caused the OH so soon into a 2000hr TBO...  and mags might not be OHd at the same time as the OH(?) so be sure of the actual hours on the mags...

Mags are often serviced at 500 hr intervals. Having one cut out at 300hrs is unusual and it’s problem should be easy to find...

Back to getting the data loaded up into savvy... that can reveal a lot about the challenge...

There are some types of mag failures that are hard to define, Detect, or tell why...

Timing issues, capacitors, and missing gear teeth could be related...

An engine monitor, and a run-up, will provide which spark plug stopped working, or which mag stopped working, and really set you in the right direction...

PP thoughts only, not a mechanic...

Best regards,

-a-

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15 hours ago, carusoam said:

Rough numbers...

Building a time line regarding your plane is a brilliant idea.  You get to learn a lot about it’s history...

1985 J

1600hrs TT

MOH at 1325hrs

300 hrs on the mags?  They have paperwork that says who did the OH on the mags?

Nothing stands out as an anomaly... but, I would be looking for details that caused the OH so soon into a 2000hr TBO...  and mags might not be OHd at the same time as the OH(?) so be sure of the actual hours on the mags...

Mags are often serviced at 500 hr intervals. Having one cut out at 300hrs is unusual and it’s problem should be easy to find...

Back to getting the data loaded up into savvy... that can reveal a lot about the challenge...

There are some types of mag failures that are hard to define, Detect, or tell why...

Timing issues, capacitors, and missing gear teeth could be related...

An engine monitor, and a run-up, will provide which spark plug stopped working, or which mag stopped working, and really set you in the right direction...

PP thoughts only, not a mechanic...

Best regards,

-a-

It was educational going back through the logs and trying to read some of the hand written comments. The OH was due to researching an oil leak and discovering a bad cam. The original Mag had two (I think I remember that) capacitors replaced. Yes, the Mag OH page has the dealer that did the work but I don't remember so I'll look that up again. I'll try to upload the information to SAVVY this afternoon as well.

I spent all day at the airport yesterday on a cold rainy day. I took the upper cowling off to look at the mag only to discover that it looks completely normal, then under the dash to look at the back of the switch and it too looks completely normal. Oh, and I taped up the floor where it's safe to line the mains and nose wheel to keep the parts of the plane that stick out, safe.

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What are we looking at?  It's tough to tell where you did your mag check?

What's wrong with your fuel flow?  During your startup and taxi, the minimum fuel flow you have is 3.0, and you're taxiing mostly with 4-6 gph.  That seems almost impossibly high.  I usually idle at 1.5-2.0 gph, and taxiing gets me up to 3-4 gph at the most.

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17 minutes ago, jaylw314 said:

What are we looking at?  It's tough to tell where you did your mag check?

What's wrong with your fuel flow?  During your startup and taxi, the minimum fuel flow you have is 3.0, and you're taxiing mostly with 4-6 gph.  That seems almost impossibly high.  I usually idle at 1.5-2.0 gph, and taxiing gets me up to 3-4 gph at the most.

I have no idea. This is the first time I've ever used an Engine Monitor much less one that records everything.

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1 hour ago, WaynePierce said:

I have no idea. This is the first time I've ever used an Engine Monitor much less one that records everything.

Ah, okay

51 minutes ago, teejayevans said:

It won’t usually record ground ops, if turn on RPM you can see it’s actually a flight.

Really?  My JPI EDM-700 starts recording when it's turned on.  Also, the RPM goes to 2700 at about :03, so I assumed the stuff before that has to do with the runup

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Check your settings record everything...

Also set your data collection rate to the smallest time interval possible... like 1 or 2 sec instead of 6.

Review Saavy site for collecting data... ideas...

Any haphazard approach to data collection becomes more challenging to describe what you are looking at...

be carefully and conscientious collecting data at run-up... wait long enough for the egts to rise... and return... before moving to the next switch position...

Follow the procedure close as you can...

Engineers love this stuff...

Consider a JPI file like a drawing... every line counts... in this case you have shared exactly 45 seconds of something?  That is about one or two  lines of a drawing...  and your data is being collected every five seconds...

Fun stuff eh?

Best regards,

-a-

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Wayne,

upon further review...

The graph that shows up is simplified...

When you click on it, the data and time have all the details... the seconds are appended on, giving better detail...

Find another flight’s data...

Try to find one where the chts start at OAT.

You should be able to see signatures of the engine start, leaning for taxi, run-up, departure, climb, leaning for cruise, cruise, descent, etc....

You might take notes if you are really new to this... time at each time you touch the knobs, and why...

get a really good hour long flight that has all these details nailed.  Keep it for comparison for an engine problem that shows up later...

Best regards,

-a-

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Here's a link to one of my flights. I upload all my flights to SavvyAnalysis. It's almost my best logbook.

https://savvyanalysis.com/flight/2798707/11583aa6-271d-419f-8ae7-e64b66958c7a

You can see my run-up is from about 3 min to 5 min into the graph.  Just sharing for reference. Note, this is ~2 sec resolution which is much better for analysis. 

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9 hours ago, WaynePierce said:

maybe I uploaded the wrong data. I thought it was 48 minutes which was about the right time.  Sorry for the confusion. 

Wayne, it looks like your flight was about 9:00 AM local time, assuming CDT that date. Does that sound correct? If so, you have the right data up there, but it actually looks like it started some time after you cranked your engine and had been taxiing for a while since your CHT's were already in the 200+ dF range. Or did you have to restart your engine when you did the mag check as the title of your post indicates?

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No, I definitely have the wrong data. It was about 2:00 PM local. I should have the correct data loaded in about an hour. (If nothing else surprises me at work)

 

Edited by WaynePierce
wrong when I thought I was wrong
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https://savvyanalysis.com/flight/2814068/73ca0f49-0369-45d9-9c9e-c48ca57c88b7 

This is the correct information, I just rechecked it. The flight was 48 minutes and when I clicked on the RPM tab I can definitely see where it was falling at the run up. The 200 EGT at startup makes sense as it was probably only about an hour after shut down. Just long enough to get a "Throwed Roll" from Sikeston, MO.

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Hmm, you probably should change your data recording interval to every 2 seconds instead of the default of every 6 seconds, it's hard to see any detail during the runup, if that's what I'm looking at from 0:00:15 to 0:01:15.  It still looks weird because your RPM never goes below 1200, and actually it stays above 1600 for the first two minutes.  Do you idle at 1600 RPM??

On second thought, are you taking off from a grass field or something?

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On 11/5/2018 at 11:14 AM, WaynePierce said:

Oh, and I taped up the floor where it's safe to line the mains and nose wheel to keep the parts of the plane that stick out, safe.

Hopefullly because of my hangar parking thread =)

no worries always glad to help!

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