EGT for cylinder #6 displays -99

[jhmcglynn]

My D120 displays -99 for EGT for cylinder #6 when I power it up. I thought it might have been due to a loose connection so I replaced the connectors, but that didn’t fix it.
I then connected the EGT #2 sensor to the EGT #6 wires on D120 side. EGT #6 still displayed -99, while EGT #2 which was left disconnected jumped to 380 degrees.
I then removed the D120 from the panel and confirmed the connectors to the back of the box were secured.

Have any of you seen this before? Any ideas?

 

[SV_Classic]

I don't know if your problem is similar though less extensive to this problem but this might help. It's possible it could be a half dozen things to check but I'm still kind of new at this. Sorry and good luck!

New install. First Engine Run. EGTs indicate same exact value

Just fired up a new Titan IO-340 with a new Dynon Sjyview install. before startup all EGTs read ambient temp (about 59F). Fired up engine and EGTs climb. At high idle of around 800rpm within a minute or so the EGTs all climb up to exactly 442-443F and stop there. Won't climb any higher even...

forum.flydynon.com

 

[jakej]

-99 = a disconnect, ie a bad join or probe. I should add -
Check the pins in the connector as they will move in/ out like pistons when you flex the cable sideways close to the connector. Many years ago I removed the back shell & heatshrink from the loom, then individually bent each wire to the shape required (stress relieved) for final fitup & then added the back shell - no issues there will all the installs since.
The other, normally discovered ‘fault’ is with the connector to probe joint. Earlier Dynon looms were supplied with ’el cheapo’ spade connectors - there are a few other ways of getting good/better? thermocouple joints. I’ve just used the AMP (Tyco) spades with total success & also use contact cleaner at the joint too. Using other types of connectors is time consuming & costs more too & you’ll have to cut off the connector on the probe. The above has worked for me for the last 20+ years, YMMV & good luck

 

[jhmcglynn]

-99 = a disconnect, ie a bad join or probe. I should add -
Check the pins in the connector as they will move in/ out like pistons when you flex the cable sideways close to the connector. Many years ago I removed the back shell & heatshrink from the loom, then individually bent each wire to the shape required (stress relieved) for final fitup & then added the back shell - no issues there will all the installs since.
The other, normally discovered ‘fault’ is with the connector to probe joint. Earlier Dynon looms were supplied with ’el cheapo’ spade connectors - there are a few other ways of getting good/better? thermocouple joints. I’ve just used the AMP (Tyco) spades with total success & also use contact cleaner at the joint too. Using other types of connectors is time consuming & costs more too & you’ll have to cut off the connector on the probe. The above has worked for me for the last 20+ years, YMMV & good luck

Thanks for the suggestion. I suspected that but let me explain what I did. There are 6 sets of EGT wires (2 wires each wrapped together in shielding, one yellow one red) that come from the plug on the back of the D120 and route through the firewall ending in spade connectors (I think they are male spades) in the engine compartment. Similar wires come from each EGT sensor with female spade connectors. I moved the # 6 set on the D120 side to the #2 cylinder. That left the #2 cylinder disconnected and the lead from the D120 for the #6 cylinder connected to the #2 cylinder sensor. The #6 cylinder still displayed -99 and the # 2 cylinder, which was disconnected, displayed a high temperature.

I’m waiting for a callback from Dynon Support. Fortunately, I have a spare set of EGT and CHT harnesses.

 

[jhmcglynn]

I don't know if your problem is similar though less extensive to this problem but this might help. It's possible it could be a half dozen things to check but I'm still kind of new at this. Sorry and good luck!

New install. First Engine Run. EGTs indicate same exact value

Just fired up a new Titan IO-340 with a new Dynon Sjyview install. before startup all EGTs read ambient temp (about 59F). Fired up engine and EGTs climb. At high idle of around 800rpm within a minute or so the EGTs all climb up to exactly 442-443F and stop there. Won't climb any higher even...

forum.flydynon.com

Thanks for the reply, I’m still working the issue.

 

[SV_Classic]

The #6 cylinder still displayed -99

if the problem followed to the new connection, wouldn't that indicate the sensor is bad and not the harness? Have you checked the sensor for continuity across the terminals?

 

[MikeSp]

if the problem followed to the new connection, wouldn't that indicate the sensor is bad and not the harness? Have you checked the sensor for continuity across the terminals?

I accidentally connected one EGT the wrong way, and in degrees C, the value was similar to the others, but not the same. When I started the engine, it soon moved to a red X, i e. faulty. Luckily, I spotted that the value went negative before going to the red X. Swapping the polarity corrected the values

 

[Rhino]

Thanks for posting the fix.

 

[SV_Classic]

I accidentally connected one EGT the wrong way, and in degrees C, the value was similar to the others, but not the same. When I started the engine, it soon moved to a red X, i e. faulty. Luckily, I spotted that the value went negative before going to the red X. Swapping the polarity corrected the values

it'll be interesting to see what the OP finds if he's able to get it fixed

 

[Janekom]

Me too, Following