Cylinder 1 dropped out

[Drummer]

Hi Everyone

Own a 79   Mooney  M20K 231

Last two times I went flying, the indicated Cylinder temperature On cylinder one went down to zero during the outbound leg of last weeks trip and the return leg of yesterdays trip and the engine Was noticeably running rougher . Has this happened to anyone else and if it has .....  I can imagine what the repairs May cost... just curious if this, Problem is a Major repair and the time the aircraft will be in the shop?

[carusoam]

Let’s get going drummer...

1) First part of the problem solving is to separate out real from instrumentation problems...

2) Sounds like this is real.

3) What engine monitor do you have?

4) Time to download the data from your last three flights...  are you familiar?

5) Loading the data up to the internet allows us to see what you have found...

6) are you familiar with Savvy? .com

7) Start with that...

8) No, it’s not normal for a TC’d engine to have a cylinder drop off line...

9) Something is probably messing with the fuel, air, spark, or compression...

Lets see what you have... and don’t have...

PP thoughts only. Not a mechanic...

Best regards,

-a-

[ArtVandelay]

Sensor issue, I can guarantee your cylinder was not 0°.

[kortopates]

10 minutes ago, ArtVandelay said:

Sensor issue, I can guarantee your cylinder was not 0°.

True, a  CHT won't register 0 F, but it can go offline which may be what the OP was seeing. In which case it could be a simple CHT thermocouple replacement. As Anthony says above it way to early to start pulling out the check book but to look at some data to start diagnosing the issue.

For the OP, its not hard to diagnose the issue because we'll still have EGT to corroborate with the CHT data. Follow Anthony's good advice above.

Edited April 26, 2020 by kortopates

[G-SLOT]

Last year I noticed cylinder 3 on an IO-470 lose both CHT and EGT - the whole cylinder went cold and there was a definite roughness - i.e. clearly not an indication issue. Reduced power on that engine and took it straight to maintenance after landing. Turned out both sparks needed replacing - relatively painless, made especially easier by the engine monitor showing me where to look.

[Gagarin]

 Looks like a clogged fuel injector. Remove the injector and have it cleaned.