knowledgeable peeps please....

eman1200

eman1200

Touchdown! Greaser!
Joined
Mar 10, 2013
Messages
21,718
Location
Oakland, CA
Display Name
Bro do you even lift
and Tom too..........(JK dude).

can anyone guess what the symptoms cause by this might be?

 
Lean cylinder.
 
By definition if you're guessing you're not knowledgeable, so I'd guess rough running with all that turbulating going on.
 
iflyvfr said:
By definition if you're guessing you're not knowledgeable, so I'd guess rough running with all that turbulating going on.
Click to expand...

I know exactly how it’s running, just want to see if it lines up with what other people have experienced.
 
I'm too lazy/tired to splain what I meant but I wasn't referring specifically to you. Interesting vid eman...curious to see the outcome.
 
Test all the injectors and that way you will know what is a normal flow/pattern and what is not.
 
I ultrasound (clean) my injectors if there is any suspected problem.
Has resolved a few issues over the years.
If not sure it's the injectors, do your test with them removed.
 
Non-mechanic here. What are we looking at? Are those the injector nozzles, and is that really how fast fuel is pumped into the engine? Wow.
 
Is this the cause of your RPM/power issue?

Have you swapped parts with another cylinder's fuel parts to narrow it down?
 
455 Bravo Uniform said:
Is this the cause of your RPM/power issue?

Have you swapped parts with another cylinder's fuel parts to narrow it down?
Click to expand...

mechanic said he moved the nozzle to all four lines with the same results at each. but the problem has been intermittent, making it very hard to diagnose. new nozzle has been ordered, time will tell.
 
GlennAB1 said:
Stumble when advancing throttle.
Click to expand...

big time stumble but only occasionally. like after an extensive and flawless runup as I'm tearing down the runway. looking forward to getting that fixed!
 
eman1200 said:
mechanic said he moved the nozzle to all four lines with the same results at each. but the problem has been intermittent, making it very hard to diagnose. new nozzle has been ordered, time will tell.
Click to expand...

Probably going to prove to be a good decision to change the nozzle. But just out of curiosity did your mechanic soak the nozzles in MEK or acetone to clean them before running the test?
 
Piece of debris inside fuel nozzle that gets sloshed around causing intermittent issues.
 
Ya might get some more answers if you move this from Flight Following to Maintenance.
 
I see two possibilities. Either one nozzle is restricted by a foreign object or the other does not have the proper orifice installed. The Lycoming nozzles are not one piece, and if the orifice is missing they will allow more fuel to one cylinder. I would have to see the process in person and compare flows to the other cylinders.
 
Norman said:
I see two possibilities. Either one nozzle is restricted by a foreign object or the other does not have the proper orifice installed. The Lycoming nozzles are not one piece, and if the orifice is missing they will allow more fuel to one cylinder. I would have to see the process in person and compare flows to the other cylinders.
Click to expand...

well I did ask if it makes sense to replace all 4 nozzles at once instead of just one. at that time, based on the tests he performed, he said just the one should suffice. but if this turns out to finally fix the issue, now I now that replacing those nozzles is relatively cheap and an easy fix.
 
Would this be an opportune time to install GAMIjectors?
 
iamtheari said:
Would this be an opportune time to install GAMIjectors?
Click to expand...

it was def a thought but it came down to not having an engine monitor that pushed me towards not doing it now. well that plus the recent expenses of the purchase plus this issue. but def a thought.
 
eman1200 said:
it was def a thought but it came down to not having an engine monitor that pushed me towards not doing it now. well that plus the recent expenses of the purchase plus this issue. but def a thought.
Click to expand...
Seems reasonable. I have an engine monitor and love it, even without balanced injectors. If you do install an engine monitor later, make sure to include the fuel flow option. That wasn't done on my plane and I wish it had been.
 
There isnt much to those nozzles. I would expect there is a visual difference there. Did the airplane sit for an extended period?
 
Grum.Man said:
There isnt much to those nozzles. I would expect there is a visual difference there. Did the airplane sit for an extended period?
Click to expand...

the last owner flew it 60-80 hours a year for the last 5 years but before that it sat a lil.
 
Probably a stupid question or I missed it, but I’m guessing the new mags didn’t cure it?
 
Ryanb said:
Probably a stupid question or I missed it, but I’m guessing the new mags didn’t cure it?
Click to expand...

nope. which is always a fun conversation between a mechanic who swore the mags were toast and would resolve the issue and the owner who just spent a fkton of money on new mags which didn't fix the issue.
 
SixPapaCharlie said:
@Ted DuPuis
Click to expand...

This is the internet. Since when I am knowledgeable on the internet? ;)

What really matters when you do this test is seeing how quickly each nozzle fills up the individual cup. I couldn't tell from the video, but it actually looked like the first nozzle had a lower flow rate than the 2nd nozzle, but the 2nd one did have a more erratic flow pattern.

A more erratic flow pattern can cause a rough idle, but at power (and ROP) won't necessarily be as noticeable. A low flow rate on one injector is a problem, though, as that will lean out one particular cylinder. On an angle valve 360, you can actually get into detonation if the conditions are right, so that would be a concern.

While GAMIs work very well on Continentals, my personal experience on Lycomings is that they haven't done all that much. Now, some disagree with me, so again my statement based only on my personal experience.

I would take all 4 injectors out and soak them in Hoppes for an hour or two, then clean them off with brake cleaner and put them back in and fly it. Although the recommendation is to do this every 100 hours or so, I've found a number of mechanics (or owners) never do this step. It makes a difference. My bet is that after you do this, it will run better. Here's my personal story that convinced me on the benefit of injector cleaning.

My Aztec (like other legacy aircraft with mechanical fuel injection) had a "fuel flow" gauge that was actually based on pressure to the fuel distributor. As you know, a clogged injector will raise pressure in the fuel system since you're reducing the outlet flow rate, and in such a system will produce increased fuel flow. My Aztec had a fuel flow gauge like this:

SAM_7137_f51a48.JPG


Theoretically on takeoff both engines should be around 24 GPH. When I first bought it, one of the engines (I think the left) the needle went past redline and ended up about on the number 18 for the other side engine. The other engine went up around to redline. My mechanic insisted that the gauge was faulty, and I didn't really know enough at the time to argue with him, nor did I know enough to know what the performance of the plane really should be.

Fast forward a few months and I decided that I should clean the injectors since Lycoming says you should, even though my mechanic disagreed. So pulled all 12 injectors (6 per side), and soaked them in Hoppes for an hour. The Hoppes turned BLACK and you couldn't even see the injector in it, this was the case for all 6 injectors on the one side. The other side wasn't quite as bad, but was still pretty bad. After it was done I put everything back together and did once around the patch. Both engines went up to 24 GPH on the fuel flow gauge, and the thing felt like it had gained 100 HP on takeoff. The one side was so bad that I'm pretty sure it was running LOP at takeoff power. That said, it still ran smooth. The 6-cylinders (especially on twins) tend to run a lot smoother.

Summary: Clean your injectors.
 
eman1200 said:
nope. which is always a fun conversation between a mechanic who swore the mags were toast and would resolve the issue and the owner who just spent a fkton of money on new mags which didn't fix the issue.
Click to expand...

I haven't been following your issue, but if your mags were old (years and/or hours), this isn't a bad idea to do anyway.

But sadly, most mechanics I've come across actually aren't very good at diagnosing engine issues.
 
Ted DuPuis said:
...A more erratic flow pattern can cause a rough idle, but at power (and ROP) won't necessarily be as noticeable.....
Click to expand...

mine is the exact opposite. starts and idles perfect, burps coughs and runs rough under power.
 
eman1200 said:
mine is the exact opposite. starts and idles perfect, burps coughs and runs rough under power.
Click to expand...

It can do that, too. Either way, your injectors should be cleaned first step. What also comes to mind is potentially other components in the fuel system.

I assume your plane has a mechanical fuel flow (pressure) gauge. What are you seeing at takeoff power? How does it compare to redline?
 
You must log in or register to reply here.
Back
Top