Mating CE2 Mk2 loom with BUB R32 engine wiring

Discussion in 'VR5, VR6 & Wx' started by 1990, Oct 15, 2020.

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  1. 1990

    1990 Paid Member Paid Member

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    Morning,

    I’d previously had a Mk4 R32 loom modified to be plug and play with a BUB engine in my Mk2. Years later I’ve found out that’s not going to work right so I’m looking to start again with Mk5 wiring.

    I have a full spare set of CE2 wiring and am currently sourcing the correct wiring for the BUB engine.

    ECU work aside, how much work is involved with this part of the conversion?
     
    1990, Oct 15, 2020
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  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    depending how the loom is done it'll only need a couple mods to correct your mk4 loom to mk5, the ecu plugs are the same as is the pinout.

    the 't14a' plug needs a couple mods assuming the loom builder put it on there, lambda plugs are different but tbh you may be able to use mk4 ones? you'll need to run the canbus wiring to fusebox so you can connect a canbus tach adaptor, you can get versions which will also inject VSS back into the canbus also to keep ecu happy

    though you pretty sure you can convert the mk5 engine to work with mk4 ecu, need to replace cams and cam adjusters plus maybe a few other bits iirc. but the costs usually higher than redoing loom tbh

    if you want to make a new loom from scratch its very similar to mk4, you add the t1`4a plug on for the main sensor loom, add the dash sensor wiring into it, tap the fusebox side to the mk5 ecu wiring. try to get a loom which is uncut as much as possible, or at the very least cut after all the throttle pedal and brake/clutch switches as that makes your life much easier. then as above need the canbus wiring for your chosen adaptor to get the mk2 clocks workin
     
    rubjonny, Oct 16, 2020
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    1990 likes this.
  3. 1990

    1990 Paid Member Paid Member

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    I’ve printed off the g5bub06on file from your sig, I‘M going to look at the wires from the larger ECU plug to see how similar the Mk4 and Mk5 sections are. I think that’s going to be the hardest section for me to find for sale.
     
    1990, Oct 16, 2020
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  4. 1990

    1990 Paid Member Paid Member

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    There is a T14a on my car at the minute but I’m unsure where it goes or if it can be reused with the new Mk5 engine loom I have just bought that has:

    smaller ECU plug > engine injectors/coils etc > t14a plug

    From the other side of the T14a I have no idea so hope I can see something on the wiring diagram. I looked at it yesterday and wrote this which seems very different compared to the Mk4 diagram:
    79FE7FE5-8BC0-423D-B723-4E6F7A190F06.jpeg
     
    1990, Oct 16, 2020
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  5. 1990

    1990 Paid Member Paid Member

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    That’s something I have no clue about and there is nothing like that on my car at the minute. I wouldn’t know where to begin.
     
    1990, Oct 16, 2020
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  6. 1990

    1990 Paid Member Paid Member

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    Yes your right there but I’d feel I was taking a backward step with that.
     
    1990, Oct 16, 2020
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  7. 1990

    1990 Paid Member Paid Member

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    That’s what I’m hoping to do. I want to get the other side of the T14a right while I source the loom for the other half of the ECU.

    This is the T14a in my car and it looks to go back to the fuse box from there. I don’t want to pull the wiring out just yet because the car does run as it is.
    2DFB3E38-8C56-408A-A604-58279E3CD20E.jpeg
     
    1990, Oct 16, 2020
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  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah so you would:
    1) check if mk4 lambda will work, if not change plugs for mk5 lambda
    2) depin t14a, check each function and swap to suit mk5 side. loom builder has made life hard for you by using VW repair wires, hence why all yellow. need to label each wire. dash sensor wiring it also depends what the loom builder did with the mk4 loom, i would go thru the t14a and add wiring into the sensor harness to suit, some run separate
    3) pull and strip big ecu plug loom off so you can add the canbus wiring back in, unless loom builder extended to fusebox. its the orange twisted pair at ecu plug
    4) replace the existing tach adaptor with new one, you can remove the old rev counter wire from ecu as not active along with ecu vss wire if its there
    5) re-route the ecu relay output, on mk5 it splits into 2 wires and goes via the t14a
    6) add mk2 2 pin coolant sensor for dash, as mk5 uses a single 2 pin for ecu. as i said on fb theres a good chance the mk5 ecu sensor is same as mk2/3/4 ecu sensor, but tbh as you have a spare hole for coolant sensor just use that. if you have a mk3 4 pin coolant sensor can use that for clocks just ignore sensor pins. loom builder may have kept mk4 sensor, if so there will be a resistor spliced in for dash temp to work with it. could keep mk4 sensor as long as resistor left in, ignore the ecu pins (or try with mk5 ecu)

    T14a - R32
    1 - blk - oil pressure switch
    2 - yel/red - crankcase breather heater (ignition live)
    3 - pur/red - carbon canister
    5 - red/grn - coilpack power (ecu relay live)
    6 - blu/red - N205/308/156/80 valve (ecu relay power)
    8 - red/blk - fuel injector power (ignition live)
    9 - brn - coilpack earth
    10 - red/grn - coilpack power (ecu relay live)
    11 - pur/red - aux. coolant pump

    double check pin 3 on your loom, as on dome carbon canister is on a different plug. its an odd one as it looks liek the t14a, but 4 of the pins are blanked and its actually referred to as a 10 pin in wiring diagrams. the above in brackets refer to what the mk5 feed are originally, but for say the injectors you could run them to Z/1 like a factory mk1/2/3 injection car ecu wont mind
     
    rubjonny, Oct 16, 2020
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  9. rubjonny

    rubjonny Administrator Staff Member Admin

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    had a quick look thru the diagrams, main thing is the lambdas I recon the wiring is a bit different I'd put the mk5 plugs on if it was me. the rest of the main lives, triggers, earths al same. if you want mk5 to handle coolant pump need to add a pin to ecu for that, the empty slots on the ecu plug have pins inside so dead easy.

    though at the end of the day the amount of effort modding the loom vs starting again is probably gonna be about the same, just saves you the cost of getting new looms. but then thats offset by being able to sell on your working mk4 loom to someone who needs it. swings and roundabouts as they say
     
    rubjonny, Oct 16, 2020
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  10. 1990

    1990 Paid Member Paid Member

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    There are loads of the earlier looms on e-bay, this one for example is what I need for the big plug on the ECU but it’s early TT/Mk4

    https://www.ebay.co.uk/itm/254697498194

    No late ones though :(
     
    1990, Oct 16, 2020
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  11. 1990

    1990 Paid Member Paid Member

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    I still can’t find a Mk5 loom so have written a full list of the BUB pin outs from the ECU and will compare that to the mk4 looms that are readily available.

    On this picture it looks like anything above pin 82 is on the small ECU plug and anything 81 and below is on the big ECU plug that I need. Is that right? Does eg, T121/70 on the wiring diagram match the picture where I have put the red ‘smudge’?
    C156528F-17CA-498D-A172-302E22DD926E.jpeg
     
    1990, Oct 22, 2020
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  12. rubjonny

    rubjonny Administrator Staff Member Admin

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    the pinouts are basically the same mk4 to mk5, you'll have some different plugs for sensors and the mk5 loom has less wiring to fusebox area as no tacho/vss and theres an extra wire for coolant pump relay trigger you may want to add.

    as you say 1-81 big plug, 82 on small and pin 70 is where your mark is. if you pop out the pin holders they are numbered in the corners, much easier to work with them that way as the numbers on the main plugs can be really hard to read
     
    rubjonny, Oct 22, 2020
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    1990 likes this.
  13. 1990

    1990 Paid Member Paid Member

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    Thanks, I’ve decided not to do this myself but want to make sure I’m sending the right stuff away to be done.

    Is your waiting list really 6 months?
     
    1990, Oct 22, 2020
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  14. rubjonny

    rubjonny Administrator Staff Member Admin

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    a good loom builder should have no problems converting a mk4 to mk5 for you, but it may cost extra. my list is getting on for over a year again :lol:

    I have lots of looms to do and no free time to do them :( when will you want it by?
     
    rubjonny, Oct 22, 2020
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  15. 1990

    1990 Paid Member Paid Member

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    Monday morning before 10am? [:$]

    Andy out is very busy too so I was thinking William Skelton, he looks to do a load of Mk2 R32’s and does a postal plug’n’play service. His description is this:


    What we have here is a conversion service for your engine wiring harness to be converted so you can install your donor engine into your mk1 / mk2 / mk3 Golf / Polo / Corrado Caddy’s 2k etc

    This auction is for a loom that will start the engine but you will be required to do some work once its returned to get it fully integrated and everything to function as they should, should the standard engine be fitted. I can also do another conversion where your existing loom is integrated fully. I will mate your existing car loom to the donor loom(as in the pictures) to make your dash oil and coolant gauge work the way it should. Later models will also have the speedo/rev counter working, (This is model, spec specific and will not work with all models). This will be a full plug in and play loom with the few points to connect up, these will be clearly labelled. This harness will work as VAG intended and loom will be as OEM as possible in the bay rather than looking like its just thrown in! If you are using DBW this will all be connected and ready to plug in. Please get in touch if you wish a full integrated loom as this is not included in this listing.

    What can be converted to fit?

    3.2 both Mk4/TT and Mk5/A3

    Here’s how it works:

    You send me the loom and ECU from the donor car. The more you send the better but if there are plugs missing I can replace them, if the looms are cut this is not an issue too as I can repair them, usually at extra cost depending on how bad they are.

    Along with the details: Year, Make, Model and ECU number. (Donor Car)

    On return the harness will come pre-fused to correct factory spec. It will be wrapped in factory spec Scapa Rayon engine harness tape which will withstand heat over 140*C. The diagnostic plug is also pre wired into the harness. If your car is a non-injection system, this is not an issue as the loom can be pre-wired with a relay to control an external fuel pump. (The pump will required to be installed and wired by you
     
    1990, Oct 22, 2020
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  16. rubjonny

    rubjonny Administrator Staff Member Admin

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    this one is piggy back type loom auction, as you see you need to do a bit of work connecting up a few wires. he mentions 'fully integrated' as another service which is what my looms always are this is what 'plug and play' means in my book ;)

    can also try James E Looms on facebook he does them the way I do them but is also a very busy boy. he does tach adaptors too but they wouldn't work on the mk5 type ecu you need one of these:
    http://www.kabelbaumtechnik-wagenkn...c9f/?ObjectPath=/Shops/82054728/Products/2004

    https://vdveer-engineering.nl/index.php/en/shop/can-convertors/can-convertor-rpm-mk1-mk2-detail
     
    rubjonny, Oct 22, 2020
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  17. 1990

    1990 Paid Member Paid Member

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    Fully integrated is what I want, I wonder how much extra that is?

    The other option once I have found the other half of the loom is to drop the car and wiring off with Andyout (when he can fit me in) and then I don’t have any connections to make.
     
    1990, Oct 22, 2020
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  18. rubjonny

    rubjonny Administrator Staff Member Admin

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    shouldnt be that much extra tbh if hes getting both looms from you
     
    rubjonny, Oct 22, 2020
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  19. 1990

    1990 Paid Member Paid Member

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    I’ve made a list of the ECU pins from your Mk5 BUB diagram so will go through your Mk4 harness guide and see if I can fill in the gaps
     

    Attached Files:

    1990, Oct 26, 2020
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  20. 1990

    1990 Paid Member Paid Member

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    Ok, I now have a BUB left side loom from an A3.

    It was a complete car so no chance to pull the wiring out so I had to cut it at each side.

    Still connected I have the MAF sensor plug and both pre cat lambda plugs. The rest is cut so with the Mk5 wiring diagram I have labelled all the cuts, they are all present and correct with 2 difference: I have no wire for ‘T121/39 Clutch position sensor’ and have an extra wire in T121/44 a brown/black.



    I now have:

    6 wires for the accelerator pins33 34 35 36 72 73 KEEP

    2 wires for the High/Low canbus pins58 60 KEEP

    2 wires for the G83 Radiator Outlet Coolant Temp Sender pins17 50 DONT KNOW

    2 wires for the F Brake Light Switch pins55 56 DONT KNOW

    1 wire K-line diagnostics pin43 KEEP

    1 wire for J527 Steering Column Electrics pin38 BIN

    1 wire for N80 Charcoal Solenoid pin64 BIN

    1 wire N321 Exhaust Flap pin19 BIN

    1 wire Secondary Air Pump Relay pin46 BIN

    1 wire Alternator pin28 KEEP

    1 wire to T40/10 pin48 DONT KNOW

    1 wire bigger red/green pin3 KEEP

    1 wire to Radiator Fan pin66 BIN

    1 wire to fuse then J681 Voltage Supply Relay pin21 KEEP

    1 wire to ECU Relay Pin65 KEEP

    1 wire to D30 positive connection 30a in harness pin62 KEEP

    1 wire to ‘e’ pin23 DONT KNOW

    Loads of wires to the rear Lambdas BIN


    Phew, that’s more than I thought!!! Am I right with the wires to bin and could a loom builder work with that or is it scrap?
     
    1990, Oct 31, 2020
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