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What am I missing on this 830


Vlakvark

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Number one needs an explanation...

not only it’s CHT is low, but it has a low EGT relative to its neighbors...

Time for a GAMI spread test...

It looks like some fuel may not be going to the place it is supposed to, and it is showing up somewhere else...

As if a fuel injector may be being partially blocked...

Ready to post a downloaded pic of an engine graph. For a complete start-up to landing kind of graph? EGTs, CHTs vs. time...

I am a better pic turner, than I am a mechanic... just a PP.

See Savvy for more details...

Best regards,

-a-

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The #1is lower than the other and #4 always hot.


You’re not missing anything most likely. Welcome to air cooled engines. Just to be sure, I’d check the following in order to see if there is a way to equalize temps a bit.

1. Make sure all cooling fins are unobstructed. (We just found a Mirage with a birds nest on number 4 last week)
2. Cowl air seals in place? Making a good seal all around? Baffles in place?
3. Look for a spark plug gasket probe used on one of the cylinders, split to run the ships on board CHT gauge and the 830.
4. Is the muffler bearing tight? Use a Kanortin wrench and jiggle the Canibly pin.

(I’m almost kidding on number 4, but sometimes it is what it is)

DVA



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Most likely normal with a non-standard CHT probe in #1 - your left rear cylinders. Check@DVA number 3 item above. EGT is normal.

If it is a spark plug probe you'll want to replace it with an Adapter probe that piggy backs onto the OEM probe.
If it is a piggy back probe already, make sure its still covered with firesleeve and not exposed to air.


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As always on this site there are tons of good answers.  Take a look to see what probes you have, check baffling, fuel flow or any other issues that are air / fuel / cooling related.  If you do have a spark plug gasket probe swap it out for the piggyback probe here:

 https://www.jpinstruments.com/shop/m113-38-cht-gasket-probe/

Let me know if it can be of any more help.

Sanjeev

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I will have a look at those probes. The baffles was changed two years back to new ones. I have read an article that say you vave to clean the Gami’s at the annual. Mine is now on its 3rd annual with the Gami’s. Will get them clean. 

Thank you again for all the input. 

JT

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1 hour ago, Vlakvark said:

I will have a look at those probes. The baffles was changed two years back to new ones. I have read an article that say you vave to clean the Gami’s at the annual. Mine is now on its 3rd annual with the Gami’s. Will get them clean. 

Thank you again for all the input. 

JT

In my opinion, Gamis (nor any injector) gets "dirty" so that it needs cleaning. After all, it has a constant flow of solvent through it. That said, they can be clogged with debris that must be removed. The only time I have found one of my injectors clogged, it was apparent from the miss in the engine, that something was wrong. Has anyone here ever seen an injector with debris that needed removal without any noticeable effect on engine performance?

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13 minutes ago, DonMuncy said:

After all it has a constant flow of solvent through it.

Has anyone here ever seen an injector with debris that needed removal without any noticeable effect on engine performance?

I'm not going to give a definitive yes or no, but about 20 years ago I had a student that bought a brand-new A36 with GAMIs installed at the factory.  It ran very well and very smooothly LOP.  He/we put a lot of hours on it.

Over time, it wouldn't run smoothly lean of peak anymore.  Then, after his first annual, it was back to smooth LOP.  After that he started having the fuel injectors cleaned every 50 hours and didn't have a problem.

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2 hours ago, Vlakvark said:

I will have a look at those probes. The baffles was changed two years back to new ones. I have read an article that say you vave to clean the Gami’s at the annual. Mine is now on its 3rd annual with the Gami’s. Will get them clean. 

Thank you again for all the input. 

JT

I would advise not to run out to clean them. First measure your gami spread via the Savvy Test profile after making sure you have a 1-2 sec data capture rate to get good data. Then see what your gami spread is, only if its degraded or 0.5 or higher would cleaning be warranted. You may be surprised to realize this but the injector environment needs to be so clean that maintenance practice of cleaning injectors often does more harm by introducing debris and nicks of injector o-rings than it does good cleaning them. Which is why we recommend only cleaning them on condition i.e. when the spread degrades.  

 

41 minutes ago, DonMuncy said:

In my opinion, Gamis (nor any injector) gets "dirty" so that it needs cleaning. After all, it has a constant flow of solvent through it. That said, they can be clogged with debris that must be removed. The only time I have found one of my injectors clogged, it was apparent from the miss in the engine, that something was wrong. Has anyone here ever seen an injector with debris that needed removal without any noticeable effect on engine performance?

absolutely, for exactly the reason that @Andy95W refers to above. Virtually any pilot that has been running LOP long enough will see their gami spread degrade over time as the injectors get dirty. Maybe sometimes its just varnish buildup, but its real and from the data I see its much more common in turbo's than NA aircraft. In turbo's our injectors are also being pressurized with Upper Deck Pressure air which is another source of debris or dirt that can get in and clog the injector. Very small clogs are not going to create a rough running engine ROP but by making it peak too early it will prevent it from running LOP smoothly since the lean outlier will be flaming out while your richest is trying to get LOP. But cleaning the injectors is the first step to restoring good mixture distribution when it has degraded over time. Nevertheless, its never a good idea to adopt a cleaning schedule based on time in service, like the example A36 pilot above, because cleaning them is one of the most common causes of a partially blocked injector. They should only be cleaned when necessary.

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Savvy Test Profile is something that anyone serious about getting the MOST out of their engine, should be familiar with. And by MOST I mean the most hours, the most performance, the most efficiency, the most range, the most safety, and the most fun.

I do the inflight Mag check portion of the test about once a month. And I run the full test profile about every six months. It's easy to do, and if you really know your engine, the results should be predictable.

*you don't need GAMI's to run this test. You do need a proper engine monitor. 

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Actually if you think about shutdown the injectors do not have a constant flow of fuel.  When I shut down the fuel boils out of the lines and may leave the injector dry or nearly dry.  I'd say this could contribute to that buildup of varnish and deposits.  

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JT,

Give a quick review to what Paul @kortopates is saying...

The gami spread is a test you can run.  Easy to do.

It is named for the Gami people that sell nice fuel injectors...

The test is the same for determining if a fuel flow problem is occurring in one or more fuel injectors...

The gami injectors, properly re-installed in the right cylinders, is important... it is possible they got re-installed unknowingly, or they might just need cleaning...

An engine monitor is needed for this test... you have a good one for this.

See the Savvy site for the steps...

If you have a wide spread, there is a test called the baby food jar test, where the flow is tested in the mechanic’s shop.

It is interesting that the low CHT and the low EGT are occurring on the same cylinder...  indicating less heat being generated there, more than too much cooling happening there...

Solving problems like these often requires many small steps being defined first...

Are you able to download your data and post it?

See Savvy if you need help...

You started the ball rolling, now is the time to follow through...  :)

Best regards,

-a-

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3 hours ago, carusoam said:

JT,

Give a quick review to what Paul @kortopates is saying...

The gami spread is a test you can run.  Easy to do.

It is named for the Gami people that sell nice fuel injectors...

The test is the same for determining if a fuel flow problem is occurring in one or more fuel injectors...

The gami injectors, properly re-installed in the right cylinders, is important... it is possible they got re-installed unknowingly, or they might just need cleaning...

An engine monitor is needed for this test... you have a good one for this.

See the Savvy site for the steps...

If you have a wide spread, there is a test called the baby food jar test, where the flow is tested in the mechanic’s shop.

It is interesting that the low CHT and the low EGT are occurring on the same cylinder...  indicating less heat being generated there, more than too much cooling happening there...

Solving problems like these often requires many small steps being defined first...

Are you able to download your data and post it?

See Savvy if you need help...

You started the ball rolling, now is the time to follow through...  :)

Best regards,

-a-

I must confess. I had never done the test nor do I know if the AME had done that when they installed the injecors. I am also not familiar with the downloads. I will get the manual out again and see how to download the information. 

Thank you for everyones help here on MS. 

JT

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I must confess. I had never done the test nor do I know if the AME had done that when they installed the injecors. I am also not familiar with the downloads. I will get the manual out again and see how to download the information. 
Thank you for everyones help here on MS. 
JT

Mechanics don't do the test as part of the install. You have to fly the savvy profile to measure it. Your EDM also has to have the fuel flow option to measure it.


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2 hours ago, Vlakvark said:

I must confess. I had never done the test nor do I know if the AME had done that when they installed the injecors. I am also not familiar with the downloads. I will get the manual out again and see how to download the information. 

Thank you for everyones help here on MS. 

JT

JT,

I am like you.  

I see where you have been.  

I know where you want to go.

You have the tools.

You have been given great guidance, by knowledgeable people.

 

Work on finding the motivation to learn about all the power that you have.

Sure it helps to be mechanically inclined...

Sure it helps to be computer oriented...

and no, You don’t have to have rebuilt an engine in high school.

 

Start by reading the manual for your JPI 830...

  • there are going to be settings that you will prefer...
  • There are going to be procedures for leaning you want to be familiar with... (take good notes on these)
  • Learn What is needed to get data from your JPI onto your computer....
  • Every page is important, there aren’t that many pages... or topics.

 

Then go to the Savvy website...

  • Learn what a GAMI spread is.
  • Learn how to upload your engine data up to Savvy.
  • Or Learn to take a screenshot and share it directly here.

The coolest thing you can do... collect data for a single flight, that starts right after engine startup... and continues through the taxi/warm-up/leaning, captures all phases of the run-up, watch for EGT increase, nice and clearly, full power take-off, climb to altitude, level off, set cruise power and lean for cruise, continue through the descent and landing, before shut-down watch for rpm gain while pulling the mixture...

If you can do that... Your engine questions can get answered...

Some people like to help other people... MS has a lot of these people...

Get fired up.  Do some reading. Take some notes.  Get ready to ask some more questions...

Don’t try to hide that you don’t know how this stuff works... that won’t help anybody.  :)

We’ve all been there, the faster you get up to speed with all your tools, the better off we all will be...

Makes sense?

Best regards,

-a-

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On 11/27/2018 at 10:48 AM, gsxrpilot said:

Savvy Test Profile is something that anyone serious about getting the MOST out of their engine, should be familiar with. And by MOST I mean the most hours, the most performance, the most efficiency, the most range, the most safety, and the most fun.

I do the inflight Mag check portion of the test about once a month. And I run the full test profile about every six months. It's easy to do, and if you really know your engine, the results should be predictable.

*you don't need GAMI's to run this test. You do need a proper engine monitor. 

I would agree with @gsxrpilot and include the comment I use the Savvy Test Profile to get the LEAST from my engine. The least cost to repair problems I catch early, the least AOG time, the least worry about having engine problems suddenly appear, and the least time trying to diagnose any problems I do encounter.

I run my downloads through Savvy Analysis so I can spend more time with my mechanic. In the FBO. Drinking coffee.

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1 hour ago, Oldguy said:

I would agree with @gsxrpilot and include the comment I use the Savvy Test Profile to get the LEAST from my engine. The least cost to repair problems I catch early, the least AOG time, the least worry about having engine problems suddenly appear, and the least time trying to diagnose any problems I do encounter.

I run my downloads through Savvy Analysis so I can spend more time with my mechanic. In the FBO. Drinking coffee.

Yes! Love it!

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