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Low EGT #1 cylinder

lithium366

By lithium366
in Vintage Mooneys (pre-J models)

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lithium366 Rising Star

lithium366

Posted
Posted

Had a blast long cross country flight from Burbank to Houston yesterday. For the last 3 hours I observed that #1 cyl EGT sporadically goes down. Like jumping between 1200-1300 in cruse every second while normally 1400. To me that sounds like a failing probe because otherwise engine is running smooth but I will appreciate any advise before I go on a 8 hours flight back. Engine is IO-360-A1A on a M20E

lithium366 Rising Star

lithium366

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28 minutes ago, Guitarmaster said:

https://photos.app.goo.gl/TyMPfZ7QCtJhWdKT6

Does it look like this?

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Not sure how to read yours but if I understand correctly you have elevated EGT on #6 and #4 cylinders. If so then I have an opposite picture when one of the cylinders EGT is significantly lower than other 3 (and than that particular cylinder 5 hours ago)

Guitarmaster Veteran

Guitarmaster

Posted
Posted
Not sure how to read yours but if I understand correctly you have elevated EGT on #6 and #4 cylinders. If so then I have an opposite picture when one of the cylinders EGT is significantly lower than other 3 (and than that particular cylinder 5 hours ago)
It's actually a video, if you play it, you will see the number 6 EGT on the left engine bouncing around. If this is kind of what you're experiencing, I would say without a doubt it's a probe.

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lithium366 Rising Star

lithium366

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1 minute ago, Guitarmaster said:

It's actually a video, if you play it, you will see the number 6 EGT on the left engine bouncing around. If this is kind of what you're experiencing, I would say without a doubt it's a probe.

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Yes, kind of similar behaviour

carusoam Grand Master

carusoam

Posted
Posted

Great video Matt!  :)

 

Ilya, the EGT sensors are the most susceptible to wear because of the high temp they are sitting in...

They are pretty easy to pull out and visually inspect or test for accuracy in a glass of water, and a pot of boiling water...

dirty and loose connections are next on the list...

these sensors don’t typically go bad like a TIT sensor can... EGTs get a lot of time off between waves of exhaust... where the TIT gauge sees heat waves from every exhaust stream provided by the engine....

PP thoughts only,

best regards,

-a-

  • Like 2
DXB Grand Master

DXB

Posted
Posted
On 12/23/2019 at 12:16 PM, lithium366 said:

Had a blast long cross country flight from Burbank to Houston yesterday. For the last 3 hours I observed that #1 cyl EGT sporadically goes down. Like jumping between 1200-1300 in cruse every second while normally 1400. To me that sounds like a failing probe because otherwise engine is running smooth but I will appreciate any advise before I go on a 8 hours flight back. Engine is IO-360-A1A on a M20E

 

Also before you replace the EGT probe, tighten its connector to the harness after coating contact with Stabilant22.  That worked for me once.

 

  • Like 1
Marauder Grand Master

Marauder

Posted
Posted
Here it is on the way back: 



Check the connection between the probe and the harness. I have seen similar issues. Just follow the probe until you get to a fire sleeve. It’s under there.


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Prior owner Experienced

Prior owner

Posted
Posted

Mine is doing the exact same thing...strangely, also on cyl #1. Weird. But I was just in there installing an Airwolf oil/air separator, so I am guessing that I inadvertently mucked up a wire on the harness.

Browncbr1 Grand Master

Browncbr1

Posted
Posted (edited)
On 12/23/2019 at 12:16 PM, lithium366 said:

Had a blast long cross country flight from Burbank to Houston yesterday. For the last 3 hours I observed that #1 cyl EGT sporadically goes down. Like jumping between 1200-1300 in cruse every second while normally 1400. To me that sounds like a failing probe because otherwise engine is running smooth but I will appreciate any advise before I go on a 8 hours flight back. Engine is IO-360-A1A on a M20E

If you are running LOP, that could be a partially blocked injector.  Easy to pull injector and soak in hopps or mek..  worth checking. 

Sometimes, this can happen after switching tanks, as the fuel valve van collect debris.   I suggest doing this every annual: pull injectors, soak, and while they are soaking do the Dixie cups test while twisting the fuel valve back and forth from tank to tank rapidly to see if any debris comes out.  Continue until clear.   Do this before cleaning gascolator.  

Edited by Browncbr1
Prior owner Experienced

Prior owner

Posted
Posted
48 minutes ago, Tcraft938 said:

Is the CHT for the cylinder reasonably similar to the others and stay pretty steady in cruise?  

My CHT is staying relatively constant in cruise. Only the EGT is moving up and down.

lithium366 Rising Star

lithium366

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On 12/30/2019 at 10:29 AM, PilotCoyote said:

My CHT is staying relatively constant in cruise. Only the EGT is moving up and down.

Same for me. 

lithium366 Rising Star

lithium366

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On 12/30/2019 at 9:24 AM, Browncbr1 said:

If you are running LOP, that could be a partially blocked injector.  Easy to pull injector and soak in hopps or mek..  worth checking. 

Sometimes, this can happen after switching tanks, as the fuel valve van collect debris.   I suggest doing this every annual: pull injectors, soak, and while they are soaking do the Dixie cups test while twisting the fuel valve back and forth from tank to tank rapidly to see if any debris comes out.  Continue until clear.   Do this before cleaning gascolator.  

I am running ROP. Do you think injectors can cause these jumps in numbers?

Guitarmaster Veteran

Guitarmaster

Posted
Posted
I am running ROP. Do you think injectors can cause these jumps in numbers?
A plugged injector will make the cylinder run lean. You would see an increase in egt but it would be steady.
All your other numbers are normal. Look for what doesn't fit.

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  • Like 1
Browncbr1 Grand Master

Browncbr1

Posted
Posted (edited)
9 hours ago, lithium366 said:

I am running ROP. Do you think injectors can cause these jumps in numbers?

A partially blocked injector can cause unstable egt, causing the cylinder to go leaner.  

Ive also experienced similar symptoms due to corrosion on the end of the spring of a spark plug harness lead where it fits inside the plug.  I scraped and cleaned up inside the plug and the harness spring and it solved the issue.     But on this one, it was easy to see with an inflight lop mag check.  Egt was unstable and non rhythmic..    

Edited by Browncbr1
M20F Grand Master

M20F

Posted
Posted
On 12/24/2019 at 2:13 PM, DXB said:

 

Also before you replace the EGT probe, tighten its connector to the harness after coating contact with Stabilant22.  That worked for me once.

 

I second this.  I recently pulled a CHT probe, put the new one on, went to detach the wire that leads to cockpit, noticed said connector was detached.....

carusoam Grand Master

carusoam

Posted
Posted

Getting an EGT to oscillate in a random fashion would require a piece of FOD to be swirling around in or near the FI...

Sometimes blocking flow, sometimes not blocking flow...

This would be on the less likely end of the spectrum than what is often report for things that block fuel injectors...

PP thoughts only, not a mechanic...

Best regards,

-a-

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