Jump to content

Picture requested for under wing OAT probe location


Stephen

Recommended Posts

Installed JPI EDM 900 in my 1969 F model. The JPI supplied OAT probe is using the old,  through-windshield mounting location,  but is reading crazy numbers (i.e. starts +/- 1 degree of field temp and on switching on master slowly climbs into ridiculously high levels ...like field temp + 60-80 degrees). This behavior is both pre and post-engine start. In flight yesterday it read 154 deg F at 4500'. JPI support says this has to be pinout/grounding/interference based and cannot be a probe malfunction. My installers have checked pinout grounding and say they did it right... interference is a "go fish" issue. So, my solution is to order a new temp probe and cable and re-install it to the (preferable) under-wing location, which changes out most of the variables in the equation. I have been hitting google and MS and am finding discussions, but no pictures of an under-wing OAT location.

 

ASK:  Could I get a pic of anyone who has an OEM underwing installation. : )

 

Thanks,

 


Stephen

Link to comment
Share on other sites

The factory location in my '78 J is on the bottom of the copilot side wing on the middle of the inboard most "small" oval inspection panel.  Just outboard of the main gear and fuel tank. Sorry, I don't have a picture. 

This is the correct location.

Sent from my LG-US996 using Tapatalk

Link to comment
Share on other sites

13 minutes ago, KSMooniac said:


This is the correct location.

Sent from my LG-US996 using Tapatalk
 

So as pictured by guitarmaster above except actually mounted in the oval panel itself correct?

Link to comment
Share on other sites

Definitely mounted in the inspection panel. I think the panel is further act in the wing, though. I don't have my maintenance manual handy at work with a location in a pic. I don't think it is critical as long as it is on the bottom of the wing and out of direct sunlight, away from exhaust, etc. Outboard of the gear is the J factory location, and I have one under each wing.

Sent from my LG-US996 using Tapatalk

  • Like 2
Link to comment
Share on other sites

1 hour ago, KSMooniac said:

That is the lazy installer (or cheap owner) option...those locations are subject to direct sunlight and radiated engine heat.

Sent from my LG-US996 using Tapatalk
 

I would suppose it makes less drag and possibly less prone to icing (if the vent is closed) while giving a pretty good reading. Mine always reads within a degree of AWOS.

  • Like 2
Link to comment
Share on other sites

15 hours ago, 201er said:

I would suppose it makes less drag and possibly less prone to icing (if the vent is closed) while giving a pretty good reading. Mine always reads within a degree of AWOS.

Could be an interesting location if it gets clean airflow. 

Link to comment
Share on other sites

Out of sunlight, and away from engine and exhaust heat...

The windshield was OK for the analog gauge, but won't have the proper shared grounding for a display mounted in the instrument panel.

The factory has been installing it under the passenger side wing since the  '90s...

Best regards,

-a-

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.