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K Series EU3 Engine Loom Wiring Diagram - Updated/Corrected


revilla

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Having recently built a spare K-Series engine I had need to make an engine wiring loom from scratch. Working from the published Caterham K Series EU3 Wiring Diagram I found several problems:

  1. The diagram contains numerous errors, some of which are just irritating (e.g. ECU plug pin layout is neither a front or rear view but a mixture of the two) and some of which are serious (e.g. the VVC cam sensor wires are shown reversed and the LT coil pack connections are shown swapped over between the coil packs).
  2. Wiring which is shown as being the same on all cars actually varies between different examples. In particular the Main Relay in the MFRU is used in some cars and unused in others, as discovered when some people found additional wiring while implementing my K-Click modification.
  3. No part numbers or sources are shown for any of the connectors. Although many are standard series connectors, some such as the ECU plugs and engine loom to injector loom headers are more difficult to identify. Rover part numbers are now of little use - OEM part numbers are required.
  4. No specifications are shown for wire sizes. This may not be important when fault finding but are required when fabricating a new loom or replacement sections for repairs.
  5. (Most of) the connector pinouts are drawn looking at the front face of the plugs. when building a new loom I was mostly inserting wires into plugs from the back, and therefore had to keep swapping round all the pinouts in my head. It would have been much more useful if the pinouts were shown looking at the plug from the wire side.
  6. The diagram contains information relevant to all models, much of which is not relevant to my loom. For my purposes it would have been nice to be able to "switch off" the wiring for options which I did not have. In addition the diagram shows discreet wiring which is not part of the loom, e.g. battery and starter cables, and it would have been nice to have been able to switch these off too.

I have therefore completely reworked the wiring diagram to address all of the above and wanted to share it back to the club membership as I felt others may find it useful. I have done it as a Paint.NET project (free download for Windows here) with each of the options in a separate layer, so you can switch on and off the options relevant to your car and get a specific customised wiring diagram. I have also made flat .PNG versions of it, showing all optional wiring, in two flavours (with or without the Main Relay wiring). Download Links:

  1. Paint.NET Project (2.7MB)
  2. Full Flat .PNG (with Main Relay) (1.6MB)
  3. Full Flat .PNG (NO Main Relay) (1.6MB)

To check whether your car has the Main Relay wired in the MFRU, compare the wires connected to the plugs on the MFRU (on top of the ECU) with MFRUStandardWiring.png.0facbc153234b2700db14503b4ab0207.png diagram - if you have an extra Brown (or sometimes Brown/Blue or Brown/Pink) wire on Pin 8/8 like MFRUExtraWire88.jpg.d1f1b0a18aa206940238c5e60d65117b.jpg then your Main Relay is used (this allows the ECU to completely disconnect the supply to the engine electrics such as injectors and coil packs and reduces battery current drain through leakage).

  1. All of the known errors have been corrected. A VVC 160 engine wired exactly as per this diagram certainly runs happily. If anyone does spot any errors or omissions, please let me know and I'll be happy to try to keep this up to date as a reference. Similarly there are areas of the diagram which do not apply to my car, in particular the extra wiring for Apollo and Dry Sump Stack systems where little detail is shown for connectors etc. If anyone is able to supply me with more information on these, again I will update.
  2. As described above, I have taken into account the differences in Main Relay wiring.
  3. I have tracked down OEM and part numbers for each of the connectors. Using these I was able to source a complete set of band new connectors. Please be aware that with some connectors e.g. the multi-pin ECU plugs, there are other connectors which look almost identical but have slightly different terminal sizes etc. The part numbers shown are believed to be correct.
  4. Wire colours and sizes are shown for every wire. For every single wire I both took measurements off my loom or old looms which I stripped down, then cross referenced the results with original Rover circuit diagrams. when building my loom I found it difficult to source wires in all colour combinations on 0.5mm2 and 0.75mm2 sizes, so substituted 1.0mm2 wires for these. Although this may make the loom slightly bulkier that if the original sizes were used, the number of redundant wires which I was able to omit made up for this. The only issue was that clipping the back covers onto the ECU plugs was a little tight, but manageable.
  5. On my diagram ALL CONNECTORS ARE DRAWN VIEWED FROM THE WIRING SIDE, NOT LOOKING AT THE CONNECTOR FACE. This was primarily because I drew the diagram for the purposes of constructing a new loom and this was the most useful view for me, however it is different to the convention (mostly) used by Caterham. It is at least consistent throughout.

PLEASE NOTE THAT THIS DIAGRAM APPLIES TO EU3 K SERIES ENGINES ONLY

  1. The layers available in the Paint.NET version are:"Background" - Plain white background with keys, legends and logos. You will always want to switch this layer on.
  2. "Common All Models" - As the name suggests, this layer contains wiring which is common across all K EU3 engine installations. You will always want to switch this layer on.
  3. "MFRU Output Pin 8 Used" and "MFRU Output Pin 8 Unused" (ONLY SELECT ONE OR THE OTHER) - These layers contain the two different Main Relay configurations as described above.
  4. "Separate IAT (Pre-2004 ZR)" and "IAT on MAP (All Other)" (ONLY SELECT ONE OR THE OTHER) - These layers contain the two different Intake Air Temperature Sensor configurations. The "Separate IAT (Pre-2004 ZR)" configuration is incorrectly described on the Caterham diagram as being "VVC Models Only" and the "IAT on MAP (All Other)" configuration is incorrectly described as being "Not VVC Models". As far as I can determine, for EU3 engines only VVCs originally destined for Pre-2004 MG ZRs had a separate IAT sensor on the lower inlet manifold. I believe this was as a result of using up old stock castings from earlier engines. If your engine has a green IAT sensor like IATSensorOnManifold1.jpg.2503b20d254c2e9204bceb3c05de6e49.jpg and IATSensorOnManifold2.jpg.79d33cf937c97709510612a46bc15979.jpg on the lower inlet manifold AND IT IS CONNECTED, you will want to switch on "Separate IAT (Pre-2004 ZR)", otherwise switch on "IAT on MAP (All Other)" (NOT both). WARNING: When I got my car it had no sensor on the lower manifold, however it did have an unused plug dangling where the sensor would have been. The ECU inputs were wired to this (i.e. I was wired according to "Separate IAT (Pre-2004 ZR)") instead of being wired to the combined IAT/MAP sensor. When I connected and OBDII scanner up it showed an IAT of -40C and an IAT fault logged. The engine was permanently in LOS (limp) mode with adaptive fueling disabled. The engine fitted was clearly not the one the car was wired for. I rewired the loom according to "IAT on MAP (All Other)" and everything was happy. I mention this because other people may find this or the opposite - an unused sensor on the manifold, as older manifolds may be fitted to later engines, in which case the sensor may be present simply to plug the hole but the engine will be using the combined IAT/MAP sensor.
  5. "VVC Mechanisms (VVC Only)" and "Cam Sensor (Non-VVC)" (ONLY SELECT ONE OR THE OTHER) - Switch on "VVC Mechanisms (VVC Only)" if you have a VVC engine, otherwise switch on "Cam Sensor (Non-VVC)" which contains wiring details for the 3-pin camshaft position sensor used on non-VVC engines (which use a 2-pin camshaft position sensor).
  6. "Emissions Ctrl (Non-UK)" - This layer contains details of emissions control systems not fitted to UK models including the charcoal canister purge valve and post-cat oxygen sensor. Only select this layer for export models which do have these systems fitted.
  7. "Shift Light (Supersport)" - This layer contains details of the shift light fitted to Supersport models only. From what I can see, this was implemented by reprogramming the ECU to turn on the AIR CONDITIONING at the RPM limit, and the air conditioning output of the ECU was then cunningly wired to the shift light.
  8. "Apollo & Stack Systems Only" - As mentioned above, some additional systems not implemented on my car so I was unable to add much detail over and above that on the Caterham diagram.
  9. "Injectors & Coils (Sub Loom)" - This layer contains details of the separate injector and coil pack sub-loom. This will be present on all cars but I included it as a separate layer as I wanted to be able to produce a diagram for the main loom only. Switch this layer on or off according to whether you want to show the sub-loom.
  10. "Discreet Wires (Not In Loom)" - This layer contains details of discreet wires which do not form part of the main wiring loom, such as alternator, battery and starter connections. As above, this will be present on all cars but I included it as a separate layer as I wanted to be able to produce a diagram for the main loom only. Switch this layer on or off according to whether you want to show external wiring.

I hope this is of use to people. Please feel free to feed back comments and corrections which I will endeavour to incorporate into the diagram as and when I get the time.

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  • 1 month later...

@Felixgogo - Thank you. No idea how to get it added to the FAQ, but would seem to make sense as it's the kind of reference work that people may find useful at any time in the future - do you know who I should contact?

 

PS: I see your location says Leicestershire (when not in Hong Kong). Where abouts are you? We are just outside Loughborough, so probably not far away.

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  • 2 months later...

I have the Main Relay wired on my car (brown/blue wire on pin 8/8). Is it possible to do the modification that you described in your Lowlying article? And what do I have to do with the brown/blue wire?

regards from Germany

Juergen

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  • 2 months later...

Whilst working on a loom for somebody else (with a non-VVC engine) I discovered a small error in my diagrams in the description of the 3-pin cam sensor connector C20 (which my VVC engine does not have, and so I had been working from photographs).

 

This connector, Rover part number YPC114950, is actually BMW Part Number 12-52-1-433-214 which is the "Code III" connector and NOT the corresponding "Code II" connector previously given. The connectors are identical except for the spacing of two of the keyways which prevent connectors of different Code being accidentally plugged together.

 

I've updated the original download links given in the initial post.

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Hi Andrew, yesterday My wife and returned from a 1.700 mile Trip to England. We had absolutely no technical Problems and the Weather was great - no single trop of rain! We enjoyed 9 beautifull days together with 9 other Sevens from the Caterham Car Club Deutschland.

But, what I wanted to say: My engine started always, no matter how hot it was. Even after 200 fast Miles on the Autobahn, no k- klick anymore since I have done the relais converstion as you described it in the LowFlying article.

Thank you very much!

juergen

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Juergen,

 

That's really good news and very good of you to let me know. It really sounds like it is a lot better. I'm glad to hear you had a good trip over here and our weather was kind to you. If you managed 9 days without rain you were very lucky!

 

Next time you decide to come to England, you must say hello *wavey*

 

Andrew.

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Andrew,

Next time we come over I will be happy to let you know *wavey*

Regarding the k-klick problem I guess that the supply of more Ampere has a major positive impact. Therefor the relay conversion mostly does the trick. On the Other Hand I realized that the car had some drag to start the engine after a fuel stop at the Autobahn. That means, it worked Fine, but was not so easy. I am thinking of improving the insulation of the solenoid in addition. Or maybe it would make sense to improve the cooling of the solenoid by a Special baffle plate, which Leads more airstream to the solenoid. That might be even better than wrapping the whole thing in insulation material. In any Way a nice project for winter time....

Juergen

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  • 7 months later...

Any idea why Revilla's links in the first post in this thread dodn't work for me?  They won't click through for me.  I'd love to see what's been done, especialy on the MFRU and the MAP as I'm going through a very similar excercise now.

Cheers, 

Aric

 

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Hi Shaun,

Attached to the original email I sent you was an MSWord document which I was hoping you would be able to set up as the text of a web page with links to the various files themselves. I've included in the document itself the placeholders for the links. There was also a .PDN Paint.NET project which allowed the user to select the options appropriate to their car and produce a customised wiring diagram.

I'll forward the email on to you again as the original is probably lost in the mists of time now. I would be very grateful if you could set it up somewhere in the guides section as I put quite a lot of effort into brushing up the work I had done for my own project in the hope of being able to contribute back to the wider "7" community, and I do get quite a few people contacting me to ask for the info as the original links in my post no longer work. If I could just point them back to the guides section that would be great.

Thanks,

Andrew.

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  • Support Team

Hi Andrew - I've set this up as a separate guide for now. Please check that I have understood your intention correctly and that the links work as you expect. If it's OK then I'll update the other guide to link to this new one.

New Guide

Shaun

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Shaun

Yes that looks really good, thank you. The only problem is that it seems to be serving the PDN project as a text file rather than a binary file, so it opens as garbage in the browser rather than downloading, but everything else looks spot on thanks.

Andrew.

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  • Support Team

That's weird - which browser/OS? I've just checked on Safari (which I used to write the guide) and on Windows 8/Explorer 11. My Windows machine has paint.net and opened the downloaded file.

Can you right click and download?

Shaun

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It seems to be Firefox that has the problem with it. It downloads correctly on IE and Chrome but I've tried on two different machines with Firefox and it tried to load it as text on both. Firefox is up to date (37.0.2) and Windows is genuine Windows 7 Enterprise. On firefox, yes I can right-click and download and it then opens corrrectly:

Just done a bit of digging and even on Chrome, although it works, you can see that the HTTP headers returned by the web server are wrong. The webserver needs configuring to serve .PDN files as "Content-Type:application/octet-stream" not "Content-Type:text/plain".

So the web server is telling the browser it is text, seems like IE and Chrome are being smart and overriding this whereas Firefox is doing what it has been told to do.

The HTTP headers I got when downloading were:

Accept-Ranges:bytes
Age:0
Connection:keep-alive
Content-Encoding:gzip
Content-Length:1797339
Content-Type:text/plain
Date:Mon, 27 Apr 2015 11:10:01 GMT
Last-Modified:Mon, 27 Apr 2015 10:20:08 GMT
Server:nginx
Vary:Accept-Encoding
Via:1.1 varnish
X-Pantheon-Endpoint:378a6234-08e2-4486-b084-571cf0ed85d3
X-Pantheon-Styx-Hostname:styx803cea0c
X-Styx-Build-Date:Wed Apr  8 00:26:15 UTC 2015
X-Styx-Build-Num:904
X-Styx-Build-Sha:7bb2d8bfad3980a9e38d528bfd8348ce61cc0c42
X-Styx-Req-Id:styx-38d60f76a1a814be649fa0d8913a3eec
X-Styx-Version:StyxGo
X-Varnish:274917890

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  • 2 weeks later...

Shaun,

As a temporary solution, below are direct links to the files hosted on my Google Drive. Could you possibly point the links in the guide directly at these until a solution is found to host them on the site itself please? Longer term I would prefer them to be hosted by the club just in case for example I were to move away from Google Drive, but no plans for anything that would break the links for the forseeable future.

Andrew

WiringDiagramFullMR.jpg
https://drive.google.com/uc?export=download&id=0B3kt8hAIdGcjX0h3NjBhS05UYzA


WiringDiagramFullMR.png
https://drive.google.com/uc?export=download&id=0B3kt8hAIdGcjM3JDTnNhYzBGTm8


WiringDiagramFullNoMR.jpg
https://drive.google.com/uc?export=download&id=0B3kt8hAIdGcjdFNVMWpsZC1qSVU


WiringDiagramFullNoMR.png
https://drive.google.com/uc?export=download&id=0B3kt8hAIdGcjUkNNTjJyVThkcm8


WiringDiagramKEU3.pdn
https://drive.google.com/uc?export=download&id=0B3kt8hAIdGcjRm5vUEpoeWQxQWc

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