Single EGT spiking IO-550

[Gui]

Hey guys,

We're doing skydiving with a Cessna 182P with a continental IO-550D, powerflow exhaust and GAMI injectors.

We purchased the plane a few years ago and after running it for a year, we noticed a couple cylinders had two EGTs (1 and 4) spiking up to high 1400s seemingly randomly fairly often.
We checked the spark plugs, changed the probes to check them, checked for contamination, drained the whole fuel system, nothing seemed to be the cause.
We attributed it to the engine running towards the end of its life and worked with it (we had around 400h to run then - one season).
We found that when the EGT would start to spike, leaning would make the other EGTs creep up but the misbehaving one rejoin them and start behaving correctly again.



We've now got a new IO-550D, without the GAMI (for warranty purposes), and an EGT is still misbehaving but now it's a different one EGT 3.
We climb at maximum rate-of-climb settings, full throttle 2700 RPM, and lean the mixture to maintain EGTs around 1360.

Can anyone make sense of this?

 

[flyingcheesehead]

If the same thing is happening with two different engines, chances are that you're getting incorrect readings. Where you should start is anything that was NOT replaced at the engine swap, starting with EGT sensors and wiring.

 

[Racerx]

Would have kept the gami's and sent them the engine files.

 

[Gui]

The plan is to run through the 12 month engine warranty with the normal injectors then switch back to Gami.
We've got plenty of data files from the old engine, I'll send some to them and see what they think.
Our engineer and an engine shop around here have never seen this before.