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UBG 16 Display Issue


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Hi All,

I recently had my audio panel changed over and since then the UBG 16 is not displaying correctly. What I'm seeing now is (I think) just bars for the CHT and nothing for the EGT. The digital readout for the EGT and CHT is displayed at the bottom of the UBG 16.

Any idea what would cause that...maybe the leads are reversed in the back of the unit now? Maybe a lead isn't connected?

Edited by GeneralT001
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  • GeneralT001 changed the title to UBG 16 Display Issue

I don't work for EI, but I have a UBG-16 in my airplane, which I installed myself (under "adult" supervision).

The way the UBG-16 bar display is supposed to work is: the lit-up segments of each bar indicate EGT values.  Within each lit-up EGT bar, there is a blacked-out segment that indicates CHT.  The temperature range from bottom to top of the display is programmable (this is important, see below).  Below is a sample image.  In this example, the #4 EGT is highest (most lit-up bar segments of all four columns).  The #4 CHT is also highest (blacked-out segment is highest of all four columns).

Note that when the engine first starts, it's common to think you're not see the blacked-out segments that indicate CHT.  This is because the blacked-out segment is the lowest segment for values below the bottom range, and since it takes a while for CHTs to come up above that value, all blacked-out segments are at the bottom of the display, which just makes it look like the entire display is physically a little higher than it actually is.

The UBG-16 connects to its temperature probes via a large cannon plug that contains the wiring for all probes.  While it's possible this plug could have been left disconnected, it's extremely unlikely the CHT and EGT probes were "swapped", because it's extremely unlikely a shop would have un-pinned the individual probe connections from the cannon plug, and the plug is indexed with tabs that prevent it from being connected in an incorrect orientation.  If the plug is completely disconnected, the numeric display at the bottom will read ambient temperature, and the bar display will be typically be blank (because ambient temperature is typically outside the programmable range of each display bar).  Any chance this is what you're seeing?

Regarding programming, it is "somewhat" possible that due to actions by the shop or random events, that the range of the bars has been re-programmed to something nonsensical.  Fortunately, you don't need to do anything scary or special to check and (re)program these ranges.  The procedure is trivial, and is described on p.14 of the operating manual: https://www.iflyei.com/wp-content/uploads/OI-UBG-16-OI-Rev-B-0505991.pdf

It's possible the unit is actually damaged, as Anthony suggests.  If so, EI advertises a $349 repair rate for the UBG-16: https://www.iflyei.com/wp-content/uploads/Standard-Repair-Costs-0930-21.pdf

Hope that helps.

UBG 16 EGTCHT Engine Analyzer | Gulf Coast Avionics

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2 hours ago, Vance Harral said:

I don't work for EI, but I have a UBG-16 in my airplane, which I installed myself (under "adult" supervision).

The way the UBG-16 bar display is supposed to work is: the lit-up segments of each bar indicate EGT values.  Within each lit-up EGT bar, there is a blacked-out segment that indicates CHT.  The temperature range from bottom to top of the display is programmable (this is important, see below).  Below is a sample image.  In this example, the #4 EGT is highest (most lit-up bar segments of all four columns).  The #4 CHT is also highest (blacked-out segment is highest of all four columns).

Note that when the engine first starts, it's common to think you're not see the blacked-out segments that indicate CHT.  This is because the blacked-out segment is the lowest segment for values below the bottom range, and since it takes a while for CHTs to come up above that value, all blacked-out segments are at the bottom of the display, which just makes it look like the entire display is physically a little higher than it actually is.

The UBG-16 connects to its temperature probes via a large cannon plug that contains the wiring for all probes.  While it's possible this plug could have been left disconnected, it's extremely unlikely the CHT and EGT probes were "swapped", because it's extremely unlikely a shop would have un-pinned the individual probe connections from the cannon plug, and the plug is indexed with tabs that prevent it from being connected in an incorrect orientation.  If the plug is completely disconnected, the numeric display at the bottom will read ambient temperature, and the bar display will be typically be blank (because ambient temperature is typically outside the programmable range of each display bar).  Any chance this is what you're seeing?

Regarding programming, it is "somewhat" possible that due to actions by the shop or random events, that the range of the bars has been re-programmed to something nonsensical.  Fortunately, you don't need to do anything scary or special to check and (re)program these ranges.  The procedure is trivial, and is described on p.14 of the operating manual: https://www.iflyei.com/wp-content/uploads/OI-UBG-16-OI-Rev-B-0505991.pdf

It's possible the unit is actually damaged, as Anthony suggests.  If so, EI advertises a $349 repair rate for the UBG-16: https://www.iflyei.com/wp-content/uploads/Standard-Repair-Costs-0930-21.pdf

Hope that helps.

UBG 16 EGTCHT Engine Analyzer | Gulf Coast Avionics

Hi,

 

Thanks for the reply.

I did fly it for 7+ hrs since the audio panel was put in and its definitely not working correctly. It functioned flawlessly before the audio work so I'm assuming its something they did and they did say they unplugged it.

Ill have a look behind the panel on Sat and also take a picture of what its showing to help clarify things.

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1 hour ago, LANCECASPER said:

Could be just that the connectors aren't tight on the back.

I had a look behind the panel and I couldn't see any connectors per se just two bundles of wires going into the back of the unit. I'm going to bring it back to the outfit that did the audio panel too have them sort it out.

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It’s been a long time since I had a UBG-16 but if memory serves there are three “pigtails” coming off the instrument, one for EGT, another for CHT and the other for power etc.

This manual may help, but follow those wires coming out of the back of the instrument and I believe you will find cannon plugs within 6 inches or so

https://buy-ei.com/wp-content/uploads/II-UBG-16-Rev-A-1111981.pdf

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42 minutes ago, A64Pilot said:

It’s been a long time since I had a UBG-16 but if memory serves there are three “pigtails” coming off the instrument, one for EGT, another for CHT and the other for power etc.

This manual may help, but follow those wires coming out of the back of the instrument and I believe you will find cannon plugs within 6 inches or so

https://buy-ei.com/wp-content/uploads/II-UBG-16-Rev-A-1111981.pdf

Thanks.

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Do all CHTs read 999°F?  If so, the two 16-pin connectors are installed backwards.  The EGT bar graph is programmed to trigger at a certain temperature.  If the UBG-16 is supposed to be displaying EGTs, but receiving signal from CHTs, the bars will never be seen as the temps are not nearly hot enough.  Reversing the 16-pin plugs during maintenance is pretty common.  Swapping them should do the trick.  

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Posted (edited)
On 6/1/2022 at 3:50 PM, oregon87 said:

Do all CHTs read 999°F?  If so, the two 16-pin connectors are installed backwards.  The EGT bar graph is programmed to trigger at a certain temperature.  If the UBG-16 is supposed to be displaying EGTs, but receiving signal from CHTs, the bars will never be seen as the temps are not nearly hot enough.  Reversing the 16-pin plugs during maintenance is pretty common.  Swapping them should do the trick.  

Hi,

I think the unit is working correctly but the range of the bars is too limited...they need to go higher. The digital readout for the EGT and the CHT looks like it is accurate.

The bars do go up a little during taxi/climb, but once the engine starts to cool off they just go to one line at the bottom of the graph. I'm guessing that the temp range for the bars needs to be adjusted?

 

Tony

Edited by GeneralT001
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Was the display working correctly before the audio panel work?  If so, it is highly unlikely that whoever performed the work navigated to the deeper levels of programming in the UBG-16 to adjust the bar graph trip points.  That's not to say that it is impossible, just unlikely.  I think it's far more likely that the harnesses were temporarily disconnected to make more room for the audio panel swap.  

Numerical EGTs are displayed at the bottom left of the display and CHTs at the bottom right.  If all the cylinders show 999°F at the bottom right, the plugs are swapped.  Taking a picture of the display with the engine running and sending it to me would help.  When doing so, a pic of a few different cylinder would be beneficial.  You can either attach it here or e-mail me at support@iflyei.com.

Edited by oregon87
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7 hours ago, oregon87 said:

Was the display working correctly before the audio panel work?  If so, it is highly unlikely that whoever performed the work navigated to the deeper levels of programming in the UBG-16 to adjust the bar graph trip points.  That's not to say that it is impossible, just unlikely.  I think it's far more likely that the harnesses were temporarily disconnected to make more room for the audio panel swap.  

Numerical EGTs are displayed at the bottom left of the display and CHTs at the bottom right.  If all the cylinders show 999°F at the bottom right, the plugs are swapped.  Taking a picture of the display with the engine running and sending it to me would help.  When doing so, a pic of a few different cylinder would be beneficial.  You can either attach it here or e-mail me at support@iflyei.com.

Hi,

yes the unit worked correctly until after the audio panel upgrade...they also tried to clean up a number of other wires that seemed to be extraneous from past work?

Pretty sure no onw tried to reprogram it...that would be weird for sure :)

The EGTS and CHTS do show correct readings that change with time and movement of the throttle/prop control/mixture. Its just the range of the bars seems very limited now.

I will take a video of the UBG 16 from start up (self test) and with engine running on the ground. Give me a few hours to get it together.

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Here is the video.

You can see the UBG does its internal test fine and then I start the engine and you can see the temps increasing but the bars don't move up until about the 4:40 mark when temps get high enough....but the temps will go lower once at cruise and I only get that one bar line across all columns.

I'm thinking that I need to figure out how to set the UBG so that the bars start moving up at a lower temp?

 

Forgive the amateurish video :)

 

 

 

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Does the data not making any sense bother you at all?  :)

The CHTs shown before and after startup are all over the place…. Including some close freezing…?

They should all be reading around the same as OAT…. (Normal system test)

The voltage being read from TCs is near micro-volts….

Very tiny amounts being read very accurately….

Expect a ground wire is no longer behaving….?

Got any other sensors on the panel mis-behaving now as well?

PP thoughts only…

Best regards,

-a-

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1 hour ago, carusoam said:

Does the data not making any sense bother you at all?  :)

The CHTs shown before and after startup are all over the place…. Including some close freezing…?

They should all be reading around the same as OAT…. (Normal system test)

The voltage being read from TCs is near micro-volts….

Very tiny amounts being read very accurately….

Expect a ground wire is no longer behaving….?

Got any other sensors on the panel mis-behaving now as well?

PP thoughts only…

Best regards,

-a-

Yeah, I know, some weird stuff. especially the negative readings.

I've been back and forth with the person who did the panel work and he swears that there are no missing wires...just two bundles composed of power/ground/temps...he thinks that the wiring harnesses for those were simply plugged back in wrong...L to R and R to L....I don't know if that could cause what we are seeing?

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5 minutes ago, GeneralT001 said:

Yeah, I know, some weird stuff. especially the negative readings.

I've been back and forth with the person who did the panel work and he swears that there are no missing wires...just two bundles composed of power/ground/temps...he thinks that the wiring harnesses for those were simply plugged back in wrong...L to R and R to L....I don't know if that could cause what we are seeing?

Micro volts…

Very tiny amounts and differences…

Easily messed with by having a dirty connection, or electrical noise near by…

The engine monitor is just a volt meter and display… with the numbers calibrated for °F…

Since the temps aren’t correct with everything turned on…

See if you can get them correct when everything else is turned off… cold at the beginning of the day…

Connecting simple ground wires may show a difference if the existing ground wires have become disabled or compromised…

Pp thoughts only,

-a-

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5 minutes ago, carusoam said:

Micro volts…

Very tiny amounts and differences…

Easily messed with by having a dirty connection, or electrical noise near by…

The engine monitor is just a volt meter and display… with the numbers calibrated for °F…

Since the temps aren’t correct with everything turned on…

See if you can get them correct when everything else is turned off… cold at the beginning of the day…

Connecting simple ground wires may show a difference if the existing ground wires have become disabled or compromised…

Pp thoughts only,

-a-

No...I'm going to get an AME to sort it out.

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From what I can see, the instrument is behaving exactly as it should, with the exception of the #1 CHT.  It appears you have a loose connection at the probe, or one of the wires between the UBG-16 and the probe is shorting.  The reason the bar graph is slow to come up is the cylinder EGTs are only reporting 1050°F, or so.  The bars typically won't be too high until the temps are closer to 1200°F.  Additionally, it appears that your engine is a 4-cylinder, judging by how you toggled between cylinders 1-4.  The UBG-16 can easily be reprogrammed for a 4-cylinder using the instructionsd below:

Hold the MODE switch to the left and power up the instrument until it reads PROGRAM at the bottom of the display.  Release the switch.  Once powered, you will see EGT 1-6, with the 6 flashing.  Use the STEP switch and toggle it a couple of times to the left to where it reads EGT 1-4.  Press and hold the MODE switch to the left until it reads END.  This will save the programming. 

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4 hours ago, oregon87 said:

From what I can see, the instrument is behaving exactly as it should, with the exception of the #1 CHT.  It appears you have a loose connection at the probe, or one of the wires between the UBG-16 and the probe is shorting.  The reason the bar graph is slow to come up is the cylinder EGTs are only reporting 1050°F, or so.  The bars typically won't be too high until the temps are closer to 1200°F.  Additionally, it appears that your engine is a 4-cylinder, judging by how you toggled between cylinders 1-4.  The UBG-16 can easily be reprogrammed for a 4-cylinder using the instructionsd below:

Hold the MODE switch to the left and power up the instrument until it reads PROGRAM at the bottom of the display.  Release the switch.  Once powered, you will see EGT 1-6, with the 6 flashing.  Use the STEP switch and toggle it a couple of times to the left to where it reads EGT 1-4.  Press and hold the MODE switch to the left until it reads END.  This will save the programming. 

Hi,

Thanks for that. I appreciate the info and it puts my mind at ease. I'll keep that programming info and see how it goes.

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