Engine misfire on climb and cruise

[redbaron1982]

Hey guys, yesterday I was doing pattern work with my CFI for the transition training and we felt a couple of misfires, the first one on the climb out after the second TO of the day. You can see that before the next TO (3rd one) we did a runup and everything looked ok. But we kept having some misfires while climbing out or at cruise, on both tanks.

This is the link to Savvy: https://apps.savvyaviation.com/beta/shared/flight/6722994/0f7ce7f1-730e-4526-8f41-e9d9caad11c1

I've already requested them to do an analysis of the flight, but additional opinions are always welcome.

BTW: the oil pressure is not working ok in the GI275 (it is in the old analogue gauge and was in the green, between the lower limit on cruise or mid way in the green at full power)

Thanks.

[JayMatt]

sounds like the Mags, if they are worn out it will cause misfires under a load. I know cause I had one go out in flight. fun experience.... Send them to the guys in ohio if that's what it is. It's that or wires or plugs IMO. I'd bet mags tho

As another guy on here says... I'm no A&P, just a dude with an opinion. 

[redbaron1982]

5 minutes ago, JayMatt said:

sounds like the Mags, if they are worn out it will cause misfires under a load. I know cause I had one go out in flight. fun experience.... Send them to the guys in ohio if that's what it is. It's that or wires or plugs IMO. I'd bet mags tho

As another guy on here says... I'm no A&P, just a dude with an opinion. 

 

Mags were recently (10 hours) overhauled by Kelly Aero. If it's the mags then it could be something that was not left in the right way.

As additional information, the airplane has been grounded for 14 months due to a big repair, I don't know if it is something that could affect (small debris in the fuel or whatever). It's also out of a fresh annual from Maxwell.

[Shadrach]

2 hours ago, redbaron1982 said:

Hey guys, yesterday I was doing pattern work with my CFI for the transition training and we felt a couple of misfires, the first one on the climb out after the second TO of the day. You can see that before the next TO (3rd one) we did a runup and everything looked ok. But we kept having some misfires while climbing out or at cruise, on both tanks.

This is the link to Savvy: https://apps.savvyaviation.com/beta/shared/flight/6722994/0f7ce7f1-730e-4526-8f41-e9d9caad11c1

I've already requested them to do an analysis of the flight, but additional opinions are always welcome.

BTW: the oil pressure is not working ok in the GI275 (it is in the old analogue gauge and was in the green, between the lower limit on cruise or mid way in the green at full power)

Thanks.

Are you reducing RPM in the climb? Are you leaning in the pattern? I'm sure there are those that will be more skilled than I am at analyzing your data. I am finding it quite challenging differentiate data that signal a potential problem from pilot inputs on mixture MAP and RPM.  That being said, it is spark or fuel.  I don't see a significant event within the other noise. FF looks good, Fuel Pressure looks good, so the fuel pumps and servo appear to be doing their jobs. EGTs are consistent with good fuel flow and correct ignition timing. Your description reads like a momentary ingestion of water, or perhaps an ignition issue downstream of the mags (short in an ignition lead). If you can see what you believe to be your misfire manifested in the data, can you post a screenshot?

[JayMatt]

1 minute ago, redbaron1982 said:

 

Mags were recently (10 hours) overhauled by Kelly Aero. If it's the mags then it could be something that was not left in the right way.

As additional information, the airplane has been grounded for 14 months due to a big repair, I don't know if it is something that could affect (small debris in the fuel or whatever). It's also out of a fresh annual from Maxwell.

If it's only in climb out when it's under the highest load, then it's electrical imo. fuel doesn't care when it is and neither does air. Now if you are in Taxi full rich and not leaning to keep your plugs clean it could potentially be that too and just need to lean out a little bit before takeoff, not during takeoff. There are more qualified people on here to comment on the best way to do that stuff. 

[redbaron1982]

23 minutes ago, Shadrach said:

Are you reducing RPM in the climb? Are you leaning in the pattern? I'm sure there are those that will be more skilled than I am at analyzing your data. I am finding it quite challenging differentiate data that signal a potential problem from pilot inputs on mixture MAP and RPM.  That being said, it is spark or fuel.  I don't see a significant event within the other noise. FF looks good, Fuel Pressure looks good, so the servo appears to be doing it's job. EGTs are consistent with good fuel flow and correct ignition timing. Your description reads like a momentary ingestion of water, or perhaps an ignition issue downstream of the mags (short in an ignition lead). If you can see what you believe to be your misfire manifested in the data, can you post a screenshot?

I'm reducing RPM/MAP @ around 500f AGL, when I don't forget (again, transition training and complex endorsement all together). I'm leaning in the pattern and while taxiing, maybe I have to do it more aggressive.  Anyway, I'm always flying with a CFI that owns a M20J as well and have lots of hours, so I'm confident I'm not doing anything too off, otherwise he would bring it up.

One additional thing, when I swamp the tanks, there is no evidence of water and the aircraft is always hangared. What I do see, a tiny bit, are small debris, not much, but a few. Seems red, like rust. I mentioned this to the CFI that helped me bring it home (not the one doing the transition training now) and he disregarded that as not important.

[Fly Boomer]

29 minutes ago, redbaron1982 said:

I'm leaning in the pattern and while taxiing, maybe I have to do it more aggressive. 

Some say that, for taxi, it should be so lean that advancing the throttle slightly will kill the engine.  In other words, as lean as possible without killing the engine.

[Niko182]

I’d guess water in the fuel. Maybe add a bit of isopropyl alcohol in each tank and see if it goes away.

[1980Mooney]

58 minutes ago, Fly Boomer said:

Some say that, for taxi, it should be so lean that advancing the throttle slightly will kill the engine.  In other words, as lean as possible without killing the engine.

That is always a good idea.  It reduces lead fouling while idling and during taxi.  And you will never make the mistake of taking off in an overly lean mixture setting because the engine will stop as soon as you push the throttle firewall forward.  

[N201MKTurbo]

Every time my J has done this it is the points. I would take the cover off the mag and inspect the point gap. if one of them is barely opening, you need to pull the mag and reset the internal timing and point gap. I have done in without removing the mag, but it is a real PITA. 

FWIW, every time I have my mag overhauled, I redo the internal timing and point gap before putting it on. Nobody does it as good as I like.

[PT20J]

Always check the easy things first: clean injectors and spark plugs.

There is no reason to reduce power in a M20J after takeoff -- doing so only reduces climb performance. The power will reduce itself as you climb since the engine is normally aspirated. In the pattern, I use full power until levelling off and then reduce to 20". 

There is no need to mess with the mixture during pattern work as it just needlessly adds to the workload. For pattern work, I set the mixture before takeoff (full rich if at low altitudes, best power if at high altitudes) and leave it alone.

I have noticed that the IO-360 will occasionally stumble at low power settings (15" or less) when left leaned for cruise. Both my original IO-360-A3B6D with an RSA servo and Bendix mag and the replacement IO-360-A3B6 with a AvStar servo and Slick mags do this.

Skip

[Shadrach]

1 hour ago, redbaron1982 said:

I'm reducing RPM/MAP @ around 500f AGL, when I don't forget (again, transition training and complex endorsement all together). I'm leaning in the pattern and while taxiing, maybe I have to do it more aggressive.  Anyway, I'm always flying with a CFI that owns a M20J as well and have lots of hours, so I'm confident I'm not doing anything too off, otherwise he would bring it up.

One additional thing, when I swamp the tanks, there is no evidence of water and the aircraft is always hangared. What I do see, a tiny bit, are small debris, not much, but a few. Seems red, like rust. I mentioned this to the CFI that helped me bring it home (not the one doing the transition training now) and he disregarded that as not important.

The red stuff is possibly made up of bits of deteriorated sealant top coat or other debris that have been introduced over years for fueling and or occasional fuel tank services. Unlikely to be rust as there is no ferrous metal in the tank or the sump.  

Leaning for taxi is a fine habit in general, but do understand that a properly set up IO360 isn't prone to plug fouling with the mixture full rich during taxi nor is it prone to fouling at pattern power settings when full rich. Some pilots like to make complex aircraft operations more complex than needed.

If indeed you had a mag or ignition lead dropping out, it is not significant enough for me to find it in your EGT data.  Furthermore, the fact that you "feel" the sputter suggests more than mere incomplete combustion of a single plug or mag.

 

2 hours ago, JayMatt said:

If it's only in climb out when it's under the highest load, then it's electrical imo. fuel doesn't care when it is and neither does air. Now if you are in Taxi full rich and not leaning to keep your plugs clean it could potentially be that too and just need to lean out a little bit before takeoff, not during takeoff. There are more qualified people on here to comment on the best way to do that stuff. 

It's a constant speed prop, the the load is no greater in climb than in cruise.  Engine load is determined by the pilot's desired power setting not the airframe's AOA.

[PT20J]

7 minutes ago, N201MKTurbo said:

FWIW, every time I have my mag overhauled, I redo the internal timing and point gap before putting it on. Nobody does it as good as I like.

If you have Slicks, try Aircraft Magneto Service. Steve doesn't use the little timing widget but puts a big protractor on it. They don't do the duals anymore last time I checked.

[N201MKTurbo]

6 minutes ago, Shadrach said:

Unlikely to be rust as there is no ferrous metal in the tank or the sump.  

The fuel cap flanges are plated steel. along with the access cover nut plates and the fuel senders. If the plating deteriorates, they can rust.

That being said, the red stuff in the fuel is most likely deteriorated top coat.

[1980Mooney]

1 hour ago, redbaron1982 said:

One additional thing, when I swamp the tanks, there is no evidence of water and the aircraft is always hangared. What I do see, a tiny bit, are small debris, not much, but a few. Seems red, like rust. I mentioned this to the CFI that helped me bring it home (not the one doing the transition training now) and he disregarded that as not important.

 

21 minutes ago, Niko182 said:

I’d guess water in the fuel. Maybe add a bit of isopropyl alcohol in each tank and see if it goes away.

It appears that you are flying out of KSGR.  I think there was only one time in 20 years that Sugar Land had any issue with water in the fuel.  And you have it in a hangar.  So I would say water is an unlikely culprit.  Also some of that dark and red looking debris in your sample cup can also be little bits of tank sealant that has flaked off as noted by @Shadrach and @N201MKTurbo

[N201MKTurbo]

Actually, the original fuel senders were plated steel. The newer ones are all aluminum.

[N201MKTurbo]

7 minutes ago, PT20J said:

If you have Slicks, try Aircraft Magneto Service. Steve doesn't use the little timing widget but puts a big protractor on it. They don't do the duals anymore last time I checked.

Slick doesn't make a dual mag 

[Shadrach]

1 minute ago, N201MKTurbo said:

The fuel cap flanges are plated steel. If the plating deteriorates, they can rust.

That being said, the red stuff in the fuel is most likely deteriorated top coat.

I hadn't thought of that.  With regard to you mag theory, I am confused as to how this would manifest as rough running unless both mags are manifesting the symptom at the exact same time. Also, why would it be intermittent?

[Shadrach]

3 minutes ago, N201MKTurbo said:

Actually, the original fuel senders were plated steel. The newer ones are all aluminum.

Well mine are 56 years old and show no signs of corrosion but they are probably steel.

[PT20J]

1 minute ago, N201MKTurbo said:

Slick doesn't make a dual mag 

I didn't mean to imply that they did. I meant that since Cliff quit doing the Bendix dual mags, no one at Aircraft Magneto does them any more. They do the single Bendix mags and Slicks. I just wasn't sure what mags you had. 

[N201MKTurbo]

Just now, Shadrach said:

I hadn't thought of that.  With regard to you mag theory, I am confused as to how this would manifest as rough running unless both mags are manifesting the symptom at the exact same time. Also, why would it be intermittent?

When the point gap is next to nothing, it will work when the engine is cold. As it heats up the gap goes to nothing and one of the mags stops firing. The engine doesn't quit, but you can feel it. it will usually go on and off every few seconds kind of a thing. It feels like a misfire. You can see all your EGTs rise when it stops firing.

[N201MKTurbo]

1 minute ago, Shadrach said:

Well mine are 56 years old and show no signs of corrosion but they are probably steel.

If they have the long wire that goes all the way back to the base, they are lead tinned steel. If the tinning fails, you can re-tin them with a big soldering iron and some solder.

[1980Mooney]

9 minutes ago, PT20J said:

Always check the easy things first: clean injectors and spark plugs.

There is no reason to reduce power in a M20J after takeoff -- doing so only reduces climb performance. The power will reduce itself as you climb since the engine is normally aspirated. In the pattern, I use full power until levelling off and then reduce to 20". 

There is no need to mess with the mixture during pattern work as it just needlessly adds to the workload. For pattern work, I set the mixture before takeoff (full rich if at low altitudes, best power if at high altitudes) and leave it alone.

I have noticed that the IO-360 will occasionally stumble at low power settings (15" or less) when left leaned for cruise. Both my original IO-360-A3B6D with an RSA servo and Bendix mag and the replacement IO-360-A3B6 with a AvStar servo and Slick mags do this.

Skip

Agreed - I was surprised that he is reducing power, both RPM and MAP at 500 ft. AGL - well below and only half of pattern altitude.  You develop "muscle memory" and that is a bad habit to get into.  One day high density altitude, high GW, wind changes, unexpected obstacles or terrain will bite you - you may be too late to put the full power back in when situational awareness kicks your habit out of "muscle memory"...

[redbaron1982]

Now that you guys mentioned, the debris for sure are from the sealant. The color matches the sealant color.

Regarding the misfires, they were not too many, maybe in one pattern lap we had 2, and then in another we had none. The ones we had they seemed to be just one misfire, not noticeable change in RPM/MAP.

After the first couple of misfires we did a runup and both mags seemed to be ok.

[N201MKTurbo]

2 minutes ago, redbaron1982 said:

Now that you guys mentioned, the debris for sure are from the sealant. The color matches the sealant color.

Regarding the misfires, they were not too many, maybe in one pattern lap we had 2, and then in another we had none. The ones we had they seemed to be just one misfire, not noticeable change in RPM/MAP.

After the first couple of misfires we did a runup and both mags seemed to be ok.

Probably just a fouled plug.