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Libra MG ZR MEMS III Engine Loom Wiring - Plug ID 
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Post Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
Hi all,

Been spending the day sorting out the Libra engine bay wiring in anticipation of the engine going in. I'm using the MG ZR (Rover 25) engine loom that came with the engine and chopping out the old MGF loom thats in place currently as its a bit of a state.

Thanks to Michael Ross, who sent me a load of very useful wiring information, I've adapted the Excel 'superb' spreadsheet MR sent to show the connections for the Rover 25 / MGZR engine loom which should mean I'm able to connect everything up correctly after unpicking the current birds nest. If anyone has used the same engine loom and could sense check the connections I'd appreciate it.

Also, apart from two, I have a home for all the connections / plugs on the loom that aren't cut off and spliced to the Mems III, SAS or GTM loom. The two I'm unsure about are the small black plug shown in the photo between the clear and grey plugs and the black plug at the bottom, below the others. I'm pretty certain the small black plug at the top can be cut off as the Libra build manual states that one of the wires going to this plug is unused ( I traced it from the black plug pin diagram in the manual) but it would be nice to be sure. I have no idea what the plug at the bottom does?

Can anyone tell me what these are for and if I can remove them and their wires from the loom? I intend to take out all the unused wires and re-wrap the loom.

Thanks in advance.

Jamie

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Mon Mar 28, 2016 2:04 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
I couldn't find a home for that plug either (the one nearer the top in your pic) although mine was mems 2.0. I think that might be the connection for the engine bay fan? I didn't cut it off, I just taped it up. The bottom one looks like it should connect to a sensor on the engine as it is the same kind of connector that fits to things like the various pressure and temperature sensors. The colour of the wire should give you a good clue?


Mon Mar 28, 2016 8:23 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
Yes that bottom plug does look like a sensor so I've left it in place for now although it wasn't attached to anything on the engine when I got it.

The wires to it are brown/pink and solid red? I've got a MGZR workshop manual coming so might find out when I check the wiring diagrams. If only I knew someone with an MGZR :)


Wed Mar 30, 2016 8:32 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
Is it the bottom plug that you're trying to identify?
This one


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Wed Mar 30, 2016 10:41 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
If its that one, then that goes to the temperature sender which is located on the elbow of the coolant pipes. The sender is some kind of resistor which gives the ECU the information for the temperature & therefore operates the cooling fans. At least it does on my Emerald ECU, not sure about mems ECU.
Its held in place by a wire clip. The one in the pic above is my one after i broke a wire on it last year & couldn't repair it. I've ended up replacing it with 2 small spade connectors for the time being.
Pic below of how it should look.


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Thu Mar 31, 2016 10:18 am
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
Hi Sven,

It certainly looks like that type of sensor plug but I'm pretty sure it doesn't go to the water outlet sensors because the loom has two other plugs that were attached to the water outlets when I got the engine?

The wires that go to the mystery plug are a brown/pink and a solid red? Both trace up into the large MEMS 3 black ecu plug?


Mon Apr 04, 2016 7:59 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
If it is not for water it will be air inlet temperature somewhere on the induction piping/plenum
Ian


Tue Apr 05, 2016 7:39 am
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
Thanks Ian, had a look around the old engine intake system and the only sensor I can't find a plug for is the intake air temp sensor as you say. By a process of elimination, it must be that one :D

Be nice if I could confirm by looking in someone's engine bay. Anyone going to Stoneleigh running a rover 25 / mg zr engine bay loom I could look at?


Tue Apr 05, 2016 8:02 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
In that case, I think your best option is to cut the plug off (whilst leaving a suitable length of wire on it).............

And then pop it in an envelope & post it to me. :lol: :lol: :lol:

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Sat Apr 09, 2016 6:40 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
It could also be the crankshaft sensor trigged from flywheel
Ian


Sun Apr 10, 2016 6:30 pm
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Post Re: Libra MG ZR MEMS III Engine Loom Wiring - Plug ID
Sven wrote:
In that case, I think your best option is to cut the plug off (whilst leaving a suitable length of wire on it).............

And then pop it in an envelope & post it to me. :lol: :lol: :lol:



:lol: :lol: I won't have to go that far thanks Sven.

I spent some time last night with the MG ZR electrical circuit diagrams and the offending plug was actually for the exhaust flap solenoid and not needed on the Libra obviously. The other plug was for the purge valve and also not needed so both have now been cut from the loom and the whole thing cleaned up re-wrapped ready for fitting.


Sun Apr 10, 2016 7:59 pm
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