What does an intake leak look like in a turbo?

[Ragsf15e]

I have a funny #6.  On the ground (leaned out), EGT and CHT are lower than the others and it will actually stumble and 6 goes cold at 1000 rpm leaned out.  Mag check looks fine.  Climb looks normal.  Runs fine, however, I noticed in LOP cruise lower egt and higher cht than the others (and I think from the past).  I’m pulling engine data today.

What am I looking for in the engine data?  How would I flight test it?

I’m also pulling the top cowl to look around.  Is there anything/anywhere specific to look for at each junction?

Thanks!

[exM20K]

Pressurize the intake with the push side of a *clean* shop vac and hit everything with soapy water.

I've had leaks in:

• the pressure line to the MAP sender
• spark plug pressurization O-rings
• over-enthusiastic tightening of hose clamps on intake tubes
• the MAG pressurization line

Engine anomalies for the spark plug pressurization were like yours.

Engine data for the Mag line  showed unstable MAP (feedback loop w/ controller)

Engine data for MAP line showed lapsing MAP with altitude.

-dan

[Rick Junkin]

With an induction leak on a turbo, the leaking cylinder will run richer than the other cylinders in cruise at altitude. You identified  lower EGT and higher CHT running LOP, which I’d correlate with #6 possibly running ROP, potentially due to an intake leak.
EDIT: What you’re seeing on the ground at 1000RPM also correlates with a #6 induction leak, where #6 would now be running leaner than the the other cylinders.

A GAMI sweep could show you what’s happening, but there is a comparative check you can do specifically driven by setting two discrete manifold pressures and comparing the EGT changes across the cylinders. They should all be about the same. The complete details for performing this check are on the Savvy site.

ANOTHER EDIT: I couldn’t find the check on the Savvy site, so here’s what I use.

As for looking at general engine data and trying to identify it, that’s more difficult without comparing a recent flight to an historical flight before you noticed a change. It can be done but you have to look for very minute EGT deviations in the data when moving from one power setting to another.

You can also check for intake leaks on the ground with a spray bottle of soapy water and a buddy to move the prop for you.

Edited Monday at 05:59 PM by Rick Junkin
Added details

[Fly Boomer]

1 hour ago, Rick Junkin said:

I couldn’t find the check on the Savvy site, so here’s what I use.

What ap are you using for that?

[Rick Junkin]

3 minutes ago, Fly Boomer said:

What ap are you using for that?

The Foreflight checklist function.