Fuel line leak in engine?

[PhateX1337]

Just landed from 4 hour XC today - was checking the engine access panels right after flight and saw this. Honestly don’t remember seeing it before flight but suppose it could’ve been there - is this #3 fuel line leaking and that’s the blue staining on the engine side of the firewall? Or am I just losing my mind...

 

also ... wouldn’t that have caused a fire if it was leaking in flight? 

[ArtVandelay]

Check loose connections (injectors, divider, etc) first.

 

Any chance there could be a pin hole in the fuel lines?

[PhateX1337]

42 minutes ago, ArtVandelay said:

Check loose connections (injectors, divider, etc) first.

 

Any chance there could be a pin hole in the fuel lines?

you can see in the picture it looks like there is a bit of blue on the fuel line, I rubbed it off and there didn’t appear to be a pinhole there, but not sure where else the blue on the fuel line would’ve come from. Maybe it’s a tiny pinhole? Not sure how a metal one would just develop a pinhole.

 

I’ll check connections - the torque mark on the injector looked undisturbed. I did not check the divider connecting on the other side of the line though. 

[rgpilot]

I had a leak on a brand new engine O/H from Continental.  Fuel injector was very loose but still had dab on injector undisturbed. Noticed it on JPI indications for that cylinder. Running too lean. Thought I had a clogged injector and made a stop to get help. Found the side of the plane on passenger side was stained blue.

 

[EricJ]

After checking for loose fittings or cracks in the line, clean the stains off with some acetone or similar and see if they come back.   Keep an eye on it.

[RLCarter]

What are these dark spots on the injector line? They look like wear spots

 

[PT20J]

Is that GAMI tag loose enough to cause vibration damage or slide around on the line? The is an AD on the lines for recurrent inspection.

[PhateX1337]

Thanks all - I’ll check all connections tomorrow and report back. Hoping it’s just a loose injector or something similar. 

The gami tag is a bit loose so it could have worn over time, the AD inspection was done in December for these lines. 

[carusoam]

Great catch!

Surprised you didn’t sense the aroma of raw 100LL.... So much air going by, it is hard to sense even the strongest aromas....
 

Unfortunately....
That is a do not fly... (Until you know what leaked, AND have it fixed)

That much blue dye took a lot of fuel to produce...  see how far the blue dye spread.... that is Signs of raw gasoline....

That much loose fuel on top of hot engine parts will not end very well...

Oddly enough... the fuel line with the tag on it....

Check that closely... the pic doesn’t have enough clarity to it but I think RLC might be onto the answer...
 

What are the cylinder cooling fins made out..?  It looks like it may have worn through the injector line?
 

Have your mechanic find out what leaked...

If it is the injector line... it is pretty easy to replace... your logs will show what part number is in there... there are a few that look the same... with different inner diameters... getting the right part is important...

Did you have a higher than normal fuel usage to go with that?  A slightly higher than expected FF?  JPI data would be needed for this... it might be a gallon or two...

 

A most likely scenario...

Some fuel injectors don’t get put back properly... there is a vent hole that needs to be aligned properly... misplaced, it drips fuel, and has it evaporate as quickly as it comes out.... and leaves drips of dark blue fuel dye splattering around the engine...  (sound similar?)

 

PP thoughts only, great catch!    Not a mechanic...

Best regards,

-a-

[PhateX1337]

Met up with A&P today - checked torque on all injectors and all fuel lines into/out of the divider, etc. Everything checked fine. Ran the fuel pump twice to pressurize the lines and saw no leaks. Then ran the engine for a few minutes & inspected again - no leaks on the injectors, divider, or line - all checked fine.

Cleaned off the stains and will do a few laps around the pattern in the next day or two when I get a chance to see if I can replicate in normal flight, but so far all signs point to stains being from an older event - had the injectors all removed for cleaning in March by Air-Mods in NJ, so perhaps that's it?

[N201MKTurbo]

There are operating conditions that cause the injectors to up chuck some fuel out the air bleeds. There was a thread about it on here a few years ago. 

[Guest]

1 hour ago, N201MKTurbo said:

There are operating conditions that cause the injectors to up chuck some fuel out the air bleeds. There was a thread about it on here a few years ago. 

Wasn’t there a video that someone made using a GoPro mounted in their cowl that showed fuel dribbling out through the vent hole?

Clarence 

Edited June 18, 2020 by M20Doc