EMS D120 CHT #1 issue

[Vr6chris]

Hello all,

I have a weird issue with my #1 CHT. It is reading -9. I swapped wires between other CHT leads with no change. I sent the unit back to Dynon a while back and it came back with no issues noted. I was wondering if anyone else has had this issue. Thanks in advance.

Chris Pryce.

 

[Dynon]

Did it stay on with #1 on the screen? It's REALLY rare for just one CHT to be wrong owing to a problem with the device. If it didn't move on the screen, one thing to check is whether or not the #1 CHT pin(s) are well-seated in the harness (as well as checking everything from the pin to the place where you reconnected the CHT). In most cases, it's a harness or probe issue (and you seem to have eliminated the probe as the cause)

 

[Vr6chris]

Yeah, I get a -9 no matter what I do. Ive changed the wires to differnet probes with the same issue.

 

[Vr6chris]

The last thing Im going to try is to connect the wiring and probe from #1 to the aux inputs to see if it will read the temperture.

 

[jakej]

As your system is a legacy unit I'd check the pin /s for # 1 in the connector. The thermocouple wire is stiffer than standard tin plated copper & the pins will move in & out as you flex the loom near the connector. I usually bend the loom as necessary to allow the connector to easily attach to the D120/D180 to mitigate the chance of the pins retracting.
PS - same technique applies to the EMS modules for SV etc.
HTH.

 

[Vr6chris]

Ive done that with no success multiple times

 

[jakej]

Ok,it appears the probe works, never known a CHT to fail anyway. Also it seems the connections at both ends of the wiring from D120 are good too. Did you use a DMM on that wiring to check continuity or whether there is a short to ground ?
How was the firewall penetration done ? Maybe the wiring has been compromised there ? After that you’re almost out of options.

 

[Vr6chris]

Problem solved! I disabled GP input #2 and it magically started working.