Engine problem or not?

[Cruiser]

Does anyone have an idea on what happened here

 

https://www.savvyanalysis.com/flight/849251/f9d1128e-18c8-46e3-a4c0-843384e404a8

 

Continental IO-550G engine seemed to perform normal although I noticed the FF was high at 14.5 gph. Everything else seemed normal.

 

I am at a loss, all ideas are welcome.

 

thanks,

 

TomK

[ArtVandelay]

Probe failure? Easy to check, just swap with and see if problem follows the probe.

[jetdriven]

That certainly looks like a #1 CHT probe. Prrhaps it cane loose at the screw connections? Always put the new star washer between the ring terminals. It's millivolts you are measuring.

[Txbyker]

or put a blow dryer on the probe first.

 

Russ

[DonMuncy]

Hey Byron. I have seen the admonition to put the star washer between the terminals. Any idea why that would be important.

[jetdriven]

You are measuring s very small voltage and the star washer digs in to the terminals to make good electrical contact. This is a big variation from a star washer's normal job, under the head of a bolt or nut to lock it. Under most antenna mounting screws, the star washer served both purposes at once. Electrical continuity and locking function. Antennas electrically connect through the skin with mounting screws to form the ground plane. Stainless washers are preferred.

[Marauder]

Not sure how the JPI probes fail, but I would have expected it to show up on the probe monitoring:

 

Diagnostic Testing on Startup and During Flight

 

When your EDM is first turned on, all digits light up for a few seconds, permitting you to check for non-functional segments. Then each column is self-tested in sequence while the EDM tests internal components, calibration and integrity of the probes. If a problem is found, it will be displayed as OPEN PRB or CAL ERR, followed by the name of the probe or channel.

 

During flight, probes are constantly checked for inconsistent or intermittent signals. A faulty channel or probe encountered during start- up or during flight will be deleted from the sequence, producing a missing column or blank digital data. 

 

​Since the EGT for cylinder 1 is still there, it really does look like a probe failure.

[jetdriven]

Bayonet style probe could have fallen out of the head. In that case it's reading an accurate air temp. Interesting.

[M20S Driver]

I had the same problem on my IO-550 G with the EGT probe #5.  My mechanic changed the probe to fix it.  The old probe works fine at lower temperatures.  It could have been a contact problem but we put a new probe on to be sure...

[ArtVandelay]

Bayonet style probe could have fallen out of the head. In that case it's reading an accurate air temp. Interesting.

I would have expected lower than normal readings as it worked loose, OP should check previous flights looking for anomalies

[carusoam]

That has a signature of a CHT guage falling out of it's mount.

The indication isn't broken... It is reading something warm, just not cylinder head warm.

After shutdown, it warms up as if the surrounding air it is in gets warm...

Was there any odd vibration during run-up? This is the time when the probe seemed to migrate...

Chemical Engineering analysis, I'm not a mechanic...

Best regards,

-a-