EGT & CHT probe failures

[Spert]

Has anyone else experienced excessive EGT/CHT probe failures? We have had our HDX system for just under a year (135 hours) and I’ve already had to replace 2 EGT and CHT probes, then this morning one of the new EGT probes is failing again. They are easy enough to replace, but the failure rate seems excessive. I’m wondering if there is something else I should be looking at.

Failure mode is that the reading jumps all over the place and eventually X’s out, generally within the next flight or two.

 

[peter9545]

I have had a few sensor failures on my D1000 classic. The characteristics of the failures were exactly the same as you describe.

In the end I suspect poor connections from the EMS harness to the EGT sensor wire were the problem all along. Obviously I couldn't prove it as the other sensors were long gone in the bin, but after the last 'failure' I remade the connections and it's been good since. FWIW.

 

[Spert]

I have had a few sensor failures on my D1000 classic. The characteristics of the failures were exactly the same as you describe.

In the end I suspect poor connections from the EMS harness to the EGT sensor wire were the problem all along. Obviously I couldn't prove it as the other sensors were long gone in the bin, but after the last 'failure' I remade the connections and it's been good since. FWIW.

Thanks. I saw another thread that indicated connections could be the culprit and am ordering better connectors as next step in troubleshooting process.

 

[jakej]

A ‘search’ will find more than enough info to help you.

 

[Spert]

A ‘search’ will find more than enough info to help you.

Concur. That’s where I found the recommendation for the connectors. I’ve ordered them and figured I’d see if the crowd had anything else I should look at in the meantime.

 

[RB-RV9A]

Concur. That’s where I found the recommendation for the connectors. I’ve ordered them and figured I’d see if the crowd had anything else I should look at in the meantime.

Can you share of what connectors was recommended or what you got . Thanks

 

[SZPflyer]

Four out of four of my Dynon D1000 Classic's EGT Sensors (#10-01169, $39.00/ea+ at Aircraft Spruce) failed at various times, all under 300 hours TTSN. The sensors were properly installed (four inches below cylinder head); at time of each failure there was almost nothing remaining of the probe itself, having been corroded away by the harsh environment inside the exhaust. Quality of the connections was not a factor. The EGT sensors are just another consumable item that goes with the territory ($185 every 300 hours); I can live with that.

 

[Spert]

Can you share of what connectors was recommended or what you got . Thanks

Recommend solution was:

Electronics International Wire Overlap Connector / Splice OLC-2 | Aircraft Spruce

Electronics International Wire Overlap Connector / Splice OLC-2 The OLC-2 eliminates the needs for soldering, crimps, and expensive connectors, all while creating a perfect connection between two wires. The two wires are stripped 3/8 and t

www.aircraftspruce.com

I have ordered, but not received them yet. I can post an update after I see if they solve the problem.

Edited to remove picture of bad options.

 

[Spert]

Four out of four of my Dynon D1000 Classic's EGT Sensors (#10-01169, $39.00/ea+ at Aircraft Spruce) failed at various times, all under 300 hours TTSN. The sensors were properly installed (four inches below cylinder head); at time of each failure there was almost nothing remaining of the probe itself, having been corroded away by the harsh environment inside the exhaust. Quality of the connections was not a factor. The EGT sensors are just another consumable item that goes with the territory ($185 every 300 hours); I can live with that.

The cost point definitely makes it easy to use replacement as an option. My main reason for the query was the frequency with which I was seeing failures. None of my failed probes looked to be worn out. If the connector thing solves the problem, I may retry some of the old ones and save them as spares if they still work.

 

[Palmer180]

Thanks. I saw another thread that indicated connections could be the culprit and am ordering better connectors as next step in troubleshooting procWhat better connectors?

 

[Palmer180]

What better connectors? My spade type are problematic.

 

[Spert]

What better connectors? My spade type are problematic.

I put the Spruce link in post #8 to the recommended connectors I found on another thread. I have not yet tried these myself, but I have them on order.

 

[jakej]

Recommend solution was:

Electronics International Wire Overlap Connector / Splice OLC-2 | Aircraft Spruce

Electronics International Wire Overlap Connector / Splice OLC-2 The OLC-2 eliminates the needs for soldering, crimps, and expensive connectors, all while creating a perfect connection between two wires. The two wires are stripped 3/8 and t

www.aircraftspruce.com

I have ordered, but not received them yet. I can post an update after I see if they solve the problem. The original connectors are the spade and slot type that came with the equipment. See red option in this picture:
View attachment 5176

 

[jakej]

Spert - everyone of the coloured connectors you displayed & the pink ones are s…# not my opinion - just fact when used for thermocouple wires, the only crimp type that work are the AMP, or TE brand or the OLC or the 2 pin dedicated thermo couple connectors & I’ve never seen the need to use anything other than the ‘good quality’ crimp types mentioned. To qualify my experience is that I’ve done many installs (well,over 50) & had to replace only 3 probes, 2 were EGT’s & 1 x CHT ( it was damaged by the owner as he bent it when trying to get more clearance from the cowl).

 

[jakej]

SZPflyer - your experience = Four out of four of my Dynon D1000 Classic's EGT Sensors (#10-01169, $39.00/ea+ at Aircraft Spruce) failed at various times, all under 300 hours TTSN. The sensors were properly installed (four inches below cylinder head); at time of each failure there was almost nothing remaining of the probe itself, having been corroded away by the harsh environment inside the exhaust. Quality of the connections was not a factor. The EGT sensors are just another consumable item that goes with the territory ($185 every 300 hours); I can live with that.
Your experience is difficult to understand give my comment/s above. How far away are your probes from the cylinder ? If 2.5” or more then you should not have the experience you mentioned, there has to be something else going on ?

 

[Spert]

Spert - everyone of the coloured connectors you displayed & the pink ones are s…# not my opinion - just fact when used for thermocouple wires, the only crimp type that work are the AMP, or TE brand or the OLC or the 2 pin dedicated thermo couple connectors & I’ve never seen the need to use anything other than the ‘good quality’ crimp types mentioned.

Are the OLCs you reposted in post 13 any good? I saw those in another thread that had good supporting comments, so I figured I’d give them a shot. The colored connectors picture was intended to show the bad ones that came with the system. I thought RB-RV9A was asking to see both, but on second read I probably induced confusion by showing the second picture. I have updated that post to remove all reference to the bad connectors.

 

[jakej]

Spert - I have never seen the need to use the OLC’s however I also believe they work well as do the other ‘push on‘ types I mentioned - you won’t be disappointed. Btw - I also use contact cleaner on the connectors before I crimp ( probably good for the OLC’s too) as we’re measuring millivolts & any oxidisation etc could have an impact on readings.

 

[jakej]

What better connectors? My spade type are problematic.

FYI - the ONLY ones I use are as mentioned in post #14.

IF anyone still has the single conductor wire (ie 1 strand of wire) in the harness or the probe then you most probably will have ‘issues’ with temperature readings.
the post above is my trade secret #1 # 2 re the single strand of wire - is to strip 5/8” of insulation off & fold the wire 2 times, & squeeze them together, so that in effect you’ll have 3 strands inside the terminal to better ‘fill’ it & then crimp it. There is no reasonably priced tool to crimp a single (very thin) wire conductor as mentioned above. YMMV of course.

 

[Rhino]

Jake, it might be helpful if you could provide a link. Since AMP is actually a crimp method rather than a connector type, I've found that simply saying "AMP connector' sometimes confuses people when they do an internet search and come up with numerous different types of AMP connectors.

 

[jakej]

Rhino - fair enough, however I’m travelling in your country at present & can only remember the part # of the TE female crimp connector- it is 640911-1.
an update - the male tab connector is p/n 66023-2.