Dumb question on injectors

[Austintatious]

Can we as pilots clean or replace injectors?

 

I am about to buy a set of GAMI injectors and aside from putting them in, as I understand it is good practice to clean them every 100 hours.  They look easily accessible with the top cowl off.  I have been reading the maintenance manual and the R&R look s straight forward.

 

 

 

 

[gsxrpilot]

I disagree on the 100 hour cleaning schedule. Anytime they are out of the plane for cleaning, there is always the chance to contaminate them. Just a single fiber from the cloth they're sitting on after cleaning, can affect fuel flow. Also, there is solvent (100LL) flowing through them constantly. So with "infant mortality" in mind, I only clean mine when I see a problem.

I've gone to only pulling mine for cleaning when I notice a change. For example, on a recent flight, my GAMI spread was way off. One cylinder seemed to be different than usual. So we pulled that injector, cleaned in and put it back. Problem solved, GAMI spread back to normal.

Just my $0.02

[MB65E]

100% Paul!!

Not worth the potential for rejecting takeoffs. 

Run ups post MX are always fine, right up until you push the power up for take off. 

-Matt 

[pwnel]

21 minutes ago, gsxrpilot said:

I've gone to only pulling mine for cleaning when I notice a change. For example, on a recent flight, my GAMI spread was way off. One cylinder seemed to be different than usual. So we pulled that injector, cleaned in and put it back. Problem solved, GAMI spread back to normal.

Paul, is that the royal "we"?  My Savvy report is showing an overly rich #2 on the GAMI spread and before I contact GAMI for a better injector I want to clean and gap spark-plugs and clean the injector.  Never done the injectors though.   Part 43 Appendix A does mention "fuel lines" in general, so I assume one could do it as owner preventative maintenance.  If so, are there good instructions around for doing so?  Want to save myself having to take a day off to get the plane to an MSC. 

[Austintatious]

Well, I was able to find the Service manual for my engine with a google search

 

[gsxrpilot]

1 minute ago, pwnel said:

Paul, is that the royal "we"?  

LOL, I've been fortunate that I've always had super easy access to JD and his team at SWTA. So no, I didn't pull the injector myself, but they did.

[pwnel]

3 minutes ago, gsxrpilot said:

LOL, I've been fortunate that I've always had super easy access to JD and his team at SWTA. So no, I didn't pull the injector myself, but they did.

I remember, thought this might have been after your move upcountry :-)  Can't seem to find the TCM X30091 fuel injection manual as referred to in my service manual. Which means it's probably something I need my MSC to do.  (Last time it was done was actually JD too).  

[kortopates]

58 minutes ago, pwnel said:

Paul, is that the royal "we"?  My Savvy report is showing an overly rich #2 on the GAMI spread and before I contact GAMI for a better injector I want to clean and gap spark-plugs and clean the injector.  Never done the injectors though.   Part 43 Appendix A does mention "fuel lines" in general, so I assume one could do it as owner preventative maintenance.  If so, are there good instructions around for doing so?  Want to save myself having to take a day off to get the plane to an MSC. 

Cleaning an injector is only going to help a lean outlier injector - not a rich outlier. But that said, before making any injector changes, if they haven't been cleaned in some time, its best to start with known clean baseline sweep data before making any changes or you could be making the wrong kind of changes and go backwards. But with a rich outlier, you'd be hoping some the lean injectors might become richer after cleaning; possible but not likely if there isn't a specific lean outlier.  

[jaylw314]

2 hours ago, Austintatious said:

Can we as pilots clean or replace injectors?

 

I am about to buy a set of GAMI injectors and aside from putting them in, as I understand it is good practice to clean them every 100 hours.  They look easily accessible with the top cowl off.  I have been reading the maintenance manual and the R&R look s straight forward.

I suspect the official word would be "no".  Preventative maintenance allows for the replacement of "prefabricated fuel lines", with the key word being "prefabricated."  I suspect they put that word in to keep us from taking apart components of fuel lines and putting them back together like this...

[gsxrpilot]

1 hour ago, kortopates said:

Cleaning an injector is only going to help a lean outlier injector - not a rich outlier. But that said, before making any injector changes, if they haven't been cleaned in some time, its best to start with known clean baseline sweep data before making any changes or you could be making the wrong kind of changes and go backwards. But with a rich outlier, you'd be hoping some the lean injectors might become richer after cleaning; possible but not likely if there isn't a specific lean outlier.  

That was exactly my situation. Because I religiously upload my JPI data to Savvy, and a lot of seat time staring at my EDM900, I recognized immediately that I had one cylinder, #2, was way too lean. The good news was it started on the flight to SWTA. I got there and told JD that I thought the #2 injector needed cleaning. And then it was all back to normal with a good GAMI spread.

BTW... a good long inflight mag check confirmed it wasn't an ignition problem.

Have I mentioned, I can't imagine flying behind an engine that's worth more than all three of my cars put together, and not having the instrumentation to know what's going on with it every single second?

[kortopates]

4 minutes ago, gsxrpilot said:

That was exactly my situation. Because I religiously upload my JPI data to Savvy, and a lot of seat time staring at my EDM900, I recognized immediately that I had one cylinder, #2, was way too lean. The good news was it started on the flight to SWTA. I got there and told JD that I thought the #2 injector needed cleaning. And then it was all back to normal with a good GAMI spread.

BTW... a good long inflight mag check confirmed it wasn't an ignition problem.

Have I mentioned, I can't imagine flying behind an engine that's worth more than all three of my cars put together, and not having the instrumentation to know what's going on with it every single second?

Yep, it happens a lot, a partially clogged or obstructed injector that causes a elevated CHT and EGT ROP or opposite LOP. Especially on our TSIO-360 engines because we don't have anything but the fuel divider screen as a last defense to keep debris out of the injectors.

Also as you mentioned above, its so true that unnecessary cleaning is the most common form of getting a partially blocked injector. A piece of airborne lint getting in the injector is all it takes, or my suspicion is nicking the injector o-ring when installing the UDP air shroud over the injector is a common source for debris being introduced to the injector after maintenance. It can be downright frustrating when it takes a couple times to get it really cleared. Sometimes we get lucky in that going full fuel flow with full power is enough to clear it - but not often enough. Sometimes they need a deep soak to get them cleaned. 

Couldn't agree more on the engine analyzer, but too many pilots still need to learn how to properly interpret them to make the most use of them. But lots of good information out there between Mike B's books, articles & vidos, Deakin's writings on Avweb and all the APS & GAMI stuff - you can beat the APS class; too bad only the online course is still available (at least I assume it still is).

[GeeBee]

Look up the "Waddington Effect" and you will be cleaning your injectors on condition, not every 100 hours.

 

 

 

[RobertGary1]

You  also have to redo the 100 hour injector AD after servicing them.

"Thereafter, re-inspect after any maintenance is done on the engine where any clamp on a fuel injector fuel line was disconnected, moved, or loosened"

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/b39e0b81acb0f30786257ecf005d80c7/%24FILE/2015-19-07.pdf

 

-Robert

[EricJ]

7 minutes ago, RobertGary1 said:

You  also have to redo the 100 hour injector AD after servicing them.

"Thereafter, re-inspect after any maintenance is done on the engine where any clamp on a fuel injector fuel line was disconnected, moved, or loosened"

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/b39e0b81acb0f30786257ecf005d80c7/%24FILE/2015-19-07.pdf

 

-Robert

That's for the lines and clamps, though, not the nozzles/injectors.

[RobertGary1]

1 minute ago, EricJ said:

That's for the lines and clamps, though, not the nozzles/injectors.

Good luck with that. How are you going to remove the injectors without "disconnected, moved, or loosened" the lines ?

-Robert

Edited September 26, 2019 by RobertGary1

[EricJ]

Just now, RobertGary1 said:

Good luck with that. How are you going to remove the injectors without moving the lines or taking off clamps?

-Robert

Not sure what the point is.   The AD is for a visual inspection that takes about 10 seconds.

[RobertGary1]

Just now, EricJ said:

Not sure what the point is.   The AD is for a visual inspection that takes about 10 seconds.

That's different than saying you don't have to do it.

-Robert

[EricJ]

Just now, RobertGary1 said:

That's different than saying you don't have to do it.

-Robert

Did somebody say it didn't need to be done?  

[RobertGary1]

1 minute ago, EricJ said:

That's for the lines and clamps, though, not the nozzles/injectors.

Did somebody say it didn't need to be done?  

Yes. I simply said you have to do the AD. Then you replied it didn't apply to nozzels.

-Robert

Edited September 26, 2019 by RobertGary1

[EricJ]

Just now, RobertGary1 said:

Yes. I simply said you have to do the AD. Then you replied it didn't apply.

-Robert

I did not.

It is true that the AD does not apply unless the lines or clamps are moved or disconnected.   The AD is not about the nozzles, it is about the lines and clamps, and isn't a barrier to doing anything with the nozzles, anyway, since compliance involves only a simple visual inspection.

Seems akin to me to pointing out that plugs need to be torqued if they've been removed or a door needs to be relatched if opened, but that's just me.  

 

[RobertGary1]

2 minutes ago, EricJ said:

I did not.

It is true that the AD does not apply unless the lines or clamps are moved or disconnected.   The AD is not about the nozzles, it is about the lines and clamps, and isn't a barrier to doing anything with the nozzles, anyway, since compliance involves only a simple visual inspection.

Seems akin to me to pointing out that plugs need to be torqued if they've been removed or a door needs to be relatched if opened, but that's just me.  

 

When I said the AD had to be done you disagreed  by saying...

"That's for the lines and clamps, though, not the nozzles/injectors."

Which we know isn't possible.

-Robert

Edited September 26, 2019 by RobertGary1

[EricJ]

Just now, RobertGary1 said:

Not sure what your point is. I said you'll have to do the AD. You said it didn't apply if you just removed the nozzles which I don't think is possible.

-Robert

You misread.   I never said it didn't apply, just that it didn't have to do with the nozzles.    Even when the nozzles are serviced and the AD has to be applied, it's just a visual inspection.

[RobertGary1]

Just now, EricJ said:

You misread.   I never said it didn't apply, just that it didn't have to do with the nozzles.    Even when the nozzles are serviced and the AD has to be applied, it's just a visual inspection.

Well that is the AD is. So I'm not sure why we're discussing this. The AD must be done like I originally said. Why did you reply at all?

-Robert

[EricJ]

Just now, RobertGary1 said:

Well that is the AD is. So I'm not sure why we're discussing this. The AD must be done like I originally said. Why did you reply at all?

-Robert

The thread is about the injectors/nozzles.   The AD doesn't apply to those.

 

[RobertGary1]

Just now, EricJ said:

The thread is about the injectors/nozzles.   The AD doesn't apply to those.

 

Are you suggesting there is a way to remove the nozzles without the AD applying? Or are you making a theoretical argument without practical purpose?

-Robert