P2008T Gremlin / Possibly Any Tecnam Owner Might Be Able to

[bigmo]

Calling everyone with a aircraft that's right outside your door - or easy access to check this connector for me. Maybe this is just for 914s, or 914s with a Garmin package, but I am hoping this is standard across models.

I have been having a random gremlin where my oil temp (not pressure) will be rock steady at 205F, then randomly jumps around, then goes out of range for a few mins, then comes back. It's unnerving to say the least, but oil pressure stays constant and CHT is perfectly steady/green - so this HAS to be a wiring/sensor gremlin. Did some checking of the sensor connector (on my 2008T w/ 914, it's zip tied on the right/passenger side of the engine); I found a stray wire!

The stray wire (with exposed copper) HAS to have pulled out of the aircraft side of the plug. Either the crimp broke, or the solder let loose. These wires are SO fragile and at next annual I would like to rework these with automotive quality connectors. Anyhow.

My stray wire comes from the aircraft side, from the shrink wrapped bundle of 3 or 4 wires I am guessing leading to some kind of engine management hardware. The shrink wrap on mine is blue & white. The wires are all just white. I have looked through all the maintenance docs and cannot find a detailed wiring diagram anywhere. 

What I am hoping is someone has this same white/blue set of wires from the aircraft and can tell me which holes in the plug they go. I think it's 3, but might be 4.

Here's a graphic that should help a ton.

I noted on the graphic both sides have 6 single wires. I guess it's possible this is a ground or goes someplace else...but I cant help thinking this is my gremlin.

MANY thanks!

[bigmo]

Here's a closeup of the wire - you can see it has a little exposed copper, so it had to have pulled from the plug (or someplace). It certainly would not have been intentionally left raw like that.

[technammech]

Feb 12, 2024 0:22:52 GMT bigmo said:

Here's a closeup of the wire - you can see it has a little exposed copper, so it had to have pulled from the plug (or someplace). It certainly would not have been intentionally left raw like that.


View Attachment

You should be able to look in that connector and see the pins.  Just see which wires are still attached to the pins or find the one pin that does not have a wire still attached.

[bigmo]

Feb 12, 2024 13:17:39 GMT technammech said:

Feb 12, 2024 0:22:52 GMT bigmo said:

Here's a closeup of the wire - you can see it has a little exposed copper, so it had to have pulled from the plug (or someplace). It certainly would not have been intentionally left raw like that.


View Attachment

You should be able to look in that connector and see the pins.  Just see which wires are still attached to the pins or find the one pin that does not have a wire still attached.

So the interesting thing is there are six connections on both sides (all with wires). This 7th wire is the odd man out. It’s about 3/4” shy of reaching the plug - which is odd too.

I looked today, and there are definitely 3 wires in the bundle. The colors are white, white w/ orange stripe, and white w/blue stripe. My stray wire is the white w/ blue stripe.

If anyone can see that 3 wire bundle and tell me where the white w/ blue stripe goes - that’ll save me a headache!

[bigmo]

[technammech]

Feb 12, 2024 18:00:59 GMT bigmo said:

View Attachment

Then that wire was probably crimped together with another still attached.  Orange and white wire kinda looks a little big at its crimp,  might see your broken end still inside

[dannyb]

If you look closely, it certainly looks like the left side of that crimp has remnants of stranded wire in it. (I zoomed in on the image.) Might need another "clue" to confirm but looks like that broken wire needs to go to the crimp with the white/orange wire (or at least in a strain relieved connection to that wire.) Good catch technamech!

d.

[bigmo]

I noticed that too. My mechanic has a bore scope with a great camera & light. In the next day or two, we're going to check each hole and see if we can see a remnant in one of the slots or even a remnant of wire.

Hoping to hear back from Tecnam Italy in the next day or so.

[Ed Midgley]

Not sure what that wire is for but, I don’t think that is your problem. The way the system works is with an open circuit the temp goes full hot and if the wire is grounded it would go full cold. So with an open circuit you wouldn’t ever get a normal reading.
The six pin connectors are a problem and I replaced most of them. The other two circuits are coolant temp and I believe oil pressure.
For me the problem six pin connector was the one behind the gearbox.
Hope this helps
Ed

[ronin5573]

I had a similar problem. My oil pressure would jump to unbelievable readings, and then return to normal. The fix for me was the connectors for the GEA24 box ( your ems computer). It located under the right side panel. Right above where the co pilots feet would be . It’s a pain to get to but using a flat head small screw driver, make sure all the connectors are scrwed in tight. Mine were very loose and caused erratic readings

[bigmo]

Feb 13, 2024 12:44:56 GMT Ed Midgley said:

Not sure what that wire is for but, I don’t think that is your problem. The way the system works is with an open circuit the temp goes full hot and if the wire is grounded it would go full cold. So with an open circuit you wouldn’t ever get a normal reading.
The six pin connectors are a problem and I replaced most of them. The other two circuits are coolant temp and I believe oil pressure.
For me the problem six pin connector was the one behind the gearbox.
Hope this helps
Ed

Thanks Ed. Did you go with some kind of six pin connector, or bullet connect them individually (or even solder ends totally)? Considering the engine comes out maybe once a decade, just soldering the wires kind of makes sense.

[Ed Midgley]

I tried individual spade connectors but the wire gauge is so small I eventually soldered and used shrink tube.
If I have to pull the motor I’ll cut them and probably run new wires
Ed

[Ed Midgley]

Today you can get connectors that are shrink tube and have sodder in them. Just need a good heat gun and they shrink and sodder at the same time.
Ed

[bigmo]

Honestly did not know those great solder shrink connectors existed / many thanks. I’m not at all scared to solder, but I like the clean and factory look - I mean what a factory connection should look like.

Those six pin connectors look like what you get on a $79 Harbor Freight generator. Sloppy fit of the pins and plastic that hasn’t aged well.

Tecnam Italy did get back and wants me to video the wire so they can get a more wholistic look. I do appreciate them getting back in s as timely manner.

More to follow!

[technammech]

Feb 14, 2024 5:22:35 GMT bigmo said:

Honestly did not know those great solder shrink connectors existed / many thanks. I’m not at all scared to solder, but I like the clean and factory look - I mean what a factory connection should look like.

Those six pin connectors look like what you get on a $79 Harbor Freight generator. Sloppy fit of the pins and plastic that hasn’t aged well.

Tecnam Italy did get back and wants me to video the wire so they can get a more wholistic look. I do appreciate them getting back in s as timely manner.

More to follow!

That connector is a standard 6 Pin Molex.  Very common in aviation by many manufacturers.   Should not be hard to replace one if it gets crispy.  Yes the solder sleeves are the cats meow.   If it were me, I would just replace what's there.   Might be a experiment on working the pin pullers for the first time to get the pins out but pushing them into the new connector is just that.  I would replace one at a time into the new connector and make sure your orientation is right.