Hight CHT and EGT on one cylinder @ takeoff

[N131MA]

Symptom

IO-550 with GAMI injectors. Nicely balanced in cruise: GAMI spread 0.4 gal/min. At takeoff average EGT of all cylinders 1300F ... except #6 at 1450 EGT. At takeoff all CHT around 380F (hot summer day) ... except #6 quickly raising above 400F.

Diagnosis

• I ran the SavvyAnalysis in flight tests: Ignition,  mixture distribution,  induction: No findings
• Increased max fuel flow from 29 to 31 gal/h: All cylinders got richer at takeoff but #6
• Reduced RPM from 2700 to 2500 right after takeoff ... and the problem went away! #6 EGT got back to similar EGT like the older jugs and CHT fell right away. I looked like the max fuel flow to #6 was reduced. As soon as the fuel flow was reduced (reduce RPM, reduce MAP, cruise settings) everything was fine.
• I disassembled #6 fuel injector and the line from the spider to the injector. The fuel injector looked fine. When I blew air through the fuel feeder line it felt it was a bit obstructed.

Treatment

Cleaned #6 injector nozzle in ultrasound bath. Pushed a copper wire through the fuel line. Cleaned the fuel line in ultrasound bath as well. Dried and cleaned both with pressured air.

Result

Problem fixed! 

[carusoam]

Anything show up in the cleaning solution?  Some bit or speck?

Did you do a baby food jar fuel flow test? Collect all six flows into individual jars for comparison...

Thanks for sharing your findings.

Best regards,

-a-

[N131MA]

On 8/17/2018 at 7:45 AM, carusoam said:

Anything show up in the cleaning solution?  Some bit or speck?

Did you do a baby food jar fuel flow test? Collect all six flows into individual jars for comparison...

Thanks for sharing your findings.

Best regards,

-a-

I did not do the baby jar test. That would have been next step if the fix above would have failed.

I don't remember any dirt in the ultrasound bath. Both, nozzle and fuel line looked shiny and polished after cleaning.

[kortopates]

Looks like you had an obstruction in the injector line that only restricted your FF at high power causing your cyl to go lean above a certain power threshold. Good job resolving it. Given the only way to get some debris into the injector line is through the screen on the fuel divider, I'd want to dissemble the divider to check and clean the screen just in an abundance of caution to avoid seeing it happen again anytime soon.

Confused though about no fresh data on Savvy since 2016? Its good load up all your data on Savvy, you could get an automated alert if something is detected.