lean function on EDM 800 quit working

[RCBass]

Question... M20F model here. My plane just came out of annual, and now my lean function doesn't work on the EDM 800. Neither lean find "rich" or "lop" is working. When I put it in LOP mode and start leaning, it starts flashing "leanest" almost immediately, and has one long inverted bar, with all the other bars blank. I continued to lean, and it didn't correct itself. 

ROP same... starts saying "leanest" almost immediately. 

Anyone ever have this happen? JPI wasn't much help when I called them... he just said must be a loose connection somewhere. The shop said they checked all the connections and ground. I don't know... it's weird.

 

[Aerodon]

13 minutes ago, RCBass said:

Question... M20F model here. My plane just came out of annual, and now my lean function doesn't work on the EDM 800. Neither lean find "rich" or "lop" is working. When I put it in LOP mode and start leaning, it starts flashing "leanest" almost immediately, and has one long inverted bar, with all the other bars blank. I continued to lean, and it didn't correct itself. 

ROP same... starts saying "leanest" almost immediately. 

Anyone ever have this happen? JPI wasn't much help when I called them... he just said must be a loose connection somewhere. The shop said they checked all the connections and ground. I don't know... it's weird.

 

The lean function needs to see all cylinders rising so that it can determine a peak.  If one cylinders keeps dropping off the get-go, then its already peaked.  Go check your fuel flow setup, maybe they changed something at the annual?  Timing?

 

Aerodon

 

[RCBass]

1 minute ago, Aerodon said:

The lean function needs to see all cylinders rising so that it can determine a peak.  If one cylinders keeps dropping off the get-go, then its already peaked.  Go check your fuel flow setup, maybe they changed something at the annual?  Timing?

 

Aerodon

 

It is starting different too, so maybe that is a possibility. Pre-annual I'd do 4 seconds on the primer and boom... now it catches but kind of coughs to a full start. The graph seems normal for EGT and CHT in flight, it's just when I put it in lean mode that it starts going haywire. 

[Shadrach]

3 hours ago, RCBass said:

It is starting different too, so maybe that is a possibility. Pre-annual I'd do 4 seconds on the primer and boom... now it catches but kind of coughs to a full start. The graph seems normal for EGT and CHT in flight, it's just when I put it in lean mode that it starts going haywire. 

JPI seems to think that one cylinder is giving an intermittent reading.  While they're not known for their service, it makes sense. Is the same cylinder always highlighted regardless of whether you use Rich or Lean find mode?

I doubt the JPI issue is Mag driven, but if they were retimed and you are noticing a difference at start up, it might be a good idea to check the timing in the logs vs the timing stamp on the data plate.  I once had a mechanic inadvertently set my mags to 20° without verifying the 25° factory setting. Not a big deal but without adjust the lag angle, the mag was now firing at 5° ATDC at start up.  It still started acceptably but it was certainly different than before.  

[RCBass]

2 hours ago, Shadrach said:

JPI seems to think that one cylinder is giving an intermittent reading.  While they're not known for there service, it makes sense. Is the same cylinder always highlighted regardless of whether you use Rich or Lean find mode?

I doubt the JPI issue is Mag driven, but if they were retimed and you are noticing a difference at start up, it might be a good idea to check the timing in the logs vs the timing stamp on the data plate.  I once had a mechanic inadvertently set my mags to 20° without verifying the factory setting. Not a big deal but without adjust the lag angle, the mag was now firing at 5° ATDC at start up.  It still started acceptably but it was certainly different than before.  

Ok, thank you.  I'll have to fly it again and see what cylinder it was, and if it is the same. I can't remember and didn't make a note at time. The number 2 cylinder was running at about 800 degrees egt (normal is the 1300's), but they replaced the probe and it seemed to be working fine last time I flew it.  I don't know... they cleaned the fuel injectors, I really feel they must have messed up one of the probes, or a connection somehow. It worked perfect before the annual. 

Edited May 31, 2022 by RCBass

[carusoam]

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click the share button…

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There are some things that stand out easily in the graphs…

Best regards,

-a-

[RCBass]

Update- Shop inspected and cleaned every probe, flew it yesterday, back to normal. They must have gummed something up cleaning the engine during annual or something.

Working fine now... thanks for the comments.

Safe flying!

Russ

[Shadrach]

31 minutes ago, RCBass said:

Update- Shop inspected and cleaned every probe, flew it yesterday, back to normal. They must have gummed something up cleaning the engine during annual or something.

Working fine now... thanks for the comments.

Safe flying!

Russ

I’m not buying that cleaning the probes solved this. Probe connections, perhaps.

[carusoam]

2 hours ago, Shadrach said:

I’m not buying that cleaning the probes solved this. Probe connections, perhaps.

Uh Boss… we forgot to re-connect the sensors… what should we tell the customer…? 

[Shadrach]

6 minutes ago, carusoam said:

Uh Boss… we forgot to re-connect the sensors… what should we tell the customer…? 

I think the most likely scenario is that one of the connections was exposed and intermittently shorting out.