OEM MK4 management wiring => Mk1/2/3 harness install FAQ (Now with added dieselness!)

Discussion in 'Engines' started by rubjonny, Nov 8, 2013.

  1. rubjonny

    rubjonny Administrator Staff Member Admin

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    I had a bad crank sensor out of the box, it would.run fine till oil gets to 80 degrees then cut out dead till the engine cools down again
     
  2. madmanluke New Member

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    Spot on as usual. Swapped out another crank from the 28 24v. Run spot on. Frustrating how they give different behaviour.
     
  3. Mk4craigg New Member

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    Hey guys I’ve got a mk2 gtd and I’m going to convert to pd tdi, should I use the gtd loom or another ce2 loom to splice into the mk4 loom?
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    Up to you really, any mk2 engine loom is fine to use as a base. main difference is if you start with a GTI loom you have the extra wiring for the MFA included. If you don't want MFA clocks then no worries, and even if you do want to add an MFA cluster you can start with a base loom and just add the 3 wires to the engine loom needed to get the MFA working
     
  5. swordfish New Member

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    Hey guys, I have a 6n2 polo fitted with a BAM engine, it starts/runs/drives but I'm having trouble with the coolant temp sensor/wiring
    the engine is clearly over fuelling as I think it's running on a cold map all the time as when I log g62 with vcds it gives a reading of -48°c?
    tried a couple of sensors & even ran a wire direct from cts pin to pin 95 on my ecu & no change?
    Is there any way I can check this wiring somehow? does the cts wiring go via another connection somehow between it & the ecu pin?
    ecu is immo defeated & I'm still running polo 6n2 clocks so no speedo rpm either however strangely enough the temp. gauge on dash works perfect, pulling my hair out with it now not to mention how quickly its emptying my wallet due to the fuel consumption
    anyone help? please
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    what sensor have you got on there, the later green one with roundy end plug or early with square plug?

    if its got the square plug on then its been converted, need to double check how this was done because the early asnd late sensors have different pinouts. coolant sensor conversion is all covered in the bottom section of my guide :)

    the ecu coolant sensor is wired direct to the ecu plug pin 93 not 95, so that explains why your tests had no results. pin 95 is one of the coilpack triggers

    the rev counter signal from the 20v ecu and speedo signal from gearbox will work polo clocks direct, so it sounds like the loom wasn't put together quite right
     
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  7. swordfish New Member

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    Thanks mate, it WAS actually pin 93 I tried it on NOT pin 95 as I previously said sorry & no change in the -48° reading via VCDS, the sensor is the later green dual one, dash reads 90 as it should when warm, i do have a few wires unconnected coming from ecu & labelled as follows
    pink or purple with yellow trace labelled as "dash coolant sensor"(temp works on dash?)
    speedo signal- white wire
    rev counter signal-green wire
    any help @ all with where to connect these to very much appreciated
     
  8. rubjonny

    rubjonny Administrator Staff Member Admin

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    ok so on the sensor:
    1 - purple - dash temp sensor -> t14a plug on engine loom pin 4 -> clocks pin T32 blue plug pin 8
    2 - brown/white - dash temp sensor earth -> T14a/9 -> earth in dash harness
    3 - grey/green - ecu temp sensor -> ECU pin 93
    4 - brown/blue ecu temp sensor earth -> ECU pin 108

    for the dash temp maybe he added another sensor to the engine for it somewhere rather than use the MK4 version?

    for the dash cluster:
    T32 green pin 11 - grn - rev counter
    T32/28 - wht/blu - speedometer sender

    You'll want to check if t
    he speed sender wire is to the one on the gearbox, via white/blue wire pin T14a/3. the speedo sensor needs ignition live and earth on the outer pins as well.

    it may be the ECU vss signal wire from ECU pin 54, if so that needs to go on the cluster output pin T32/3 grn/wht wire. If it isn't, you need to find that and hook it up
     
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  9. swordfish New Member

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    Hi John thanks for the input mate, finally have a correct ecu temp reading :-)
    Ran a wire straight from pin 3 on cts to pin 93 on ECU & bingo!

    The car is a polo 6n2 that used to have an AUD code 1.4 engine in it, it now has a BAM from an s3 in it, I bought it partially finished(it started/stopped)so didn't wire it myself, things that work...
    ignition/oil/battery lights
    fuel gauge
    dash temp gauge
    water level
    things that dont work or lights lit on dash
    EPC light on constant
    engine management on constant
    NO REV COUNTER
    NO SPEEDO
    have 12v from outer pins of speedo plug when ignition on.

    So to clarify if you could while I'm on a roll
    when you say "T32" etc. does this refer to the green & blue plugs feeding the rear of the cluster?

    just the rev counter & speedo to suss now & I'm happy & cyber pints all round :-)

    Sorry if I'm being a bit thick but the only wiring diagrams I have are from autodata on the laptop & they're basic with just ECU pinouts really

    Thanks again for helping mate, genuinely @ my wits end with this
     
    Last edited: Dec 22, 2019
  10. rubjonny

    rubjonny Administrator Staff Member Admin

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    alright cool, some damage in the wiring loom then. might be an idea to split all the tape off for a good look, as where you get 1 damaged wire you may have more in same location depending on how it happened...

    with the engine warning lights, do you have fault codes flagged from the ECU? If so that may be why, assuming the CAN-BUS wiring was hooked up during the conversion as the physical lamp pins are normally unused on the 6N polo

    rev counter and speedo pins as above, by T32 and T32a I mean the plugs on the cluster yes,for wiring diagrams see my signature link all you'll need and more ;) Also heres a pinout of the polo ECU coloured plugs with important bits highlighted which may help:
    T10 - white
    3 - yel/red - dash temp sensor
    8 - blk/yel - carbon canister, EGR live (ignition live, fuse 30)

    T10a - green
    1 - red - permanent live to ecu (fuse 37)
    5 - red/yel - fuel injector power (fuel relay live, fuse 3)
    7 - wht/yel - immobiliser control unit (w-line to immobiliser, ECU diagnostics)

    T10b - black
    2 - blu/red - coolant level sensor
    3 - wht/blu - vehicle speed sensor signal to dash
    10 - blu/wht - vehicle speed signal from dash to ECU

    T10c - blue
    4 - wht/red - lambda probe heater (fuel relay live, fuse 1)

    T10d - red
    1 - brn/wht - fuel level sender earth (dash sensor common earth, linked to T10e/3 & dash pin T32/7)
    3 - blu - alternator L/D+ (battery warning light)
    10 - grn/blu - rev counter

    T10e - pink
    3 - brn/wht - coolant temp sensor earth (dash sensor common earth, linked to T10d/1)

    T10g - brown
    1 - red/yel - fuel relay trigger
    2 - grn - aircon
    3 - blk/gry - vehicle speed sensor live (ignition live, fuse 28)
    8 - blk - ecu power (ignition live, fuse 28)
    10 - blu/red - aircon

    T10s - light green
    4 - red/blk - starter pin 50 (cranking live)
    7 - org/blk - CAN-BUS high from ECU
    8 - blk - coil, immobiliser & speed sensor (ignition live, fuse 34)
    7 - org/brn - CAN-BUS low from ECU

    T10x - yellow
    gry/yel - airbag control unit crash signal to fuel relay
     
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  11. swordfish New Member

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    Fantastic mate! thanks very much, will have a go @ this over the holidays again.
    The car has 2 ECUs, it retains the original AUD ECU & Has the BAM ECU too to run the engine for some reason, not how I'd have done it but have to work with it now[8-}]

    With this in mind would it be possible to tap straight into the polo ECU plug wiring back to the cluster with the output wires from the BAM ECU? can I just snip the correct wire from the rear of polo ECU plug & join bam signal wire to it instead to feed cluster?

    Where does the VSS signal come from? the centre wire on sender on gearbox yes?

    I can see rpm on vcds so BAM ECU is receiving that info, would I be right saying pin 37 feeds the rpm output to cluster from the BAM ECU?

    Same signal from AUD ECU is pin 41?

    So my thinking(as the 2 ECUs are side by side in scuttle) take the output signal wire from pin 37 on BAM & tap into the pin 41 wire from AUD & it should work the rev counter?
    Or do I NEED to run BAM wire straight to cluster plug pins

    Car also has 2 separate obd ports, one for engine & other for original stuff that still reads abs stuff etc.
    Both show fault codes as expected really but the polo codes from memory are just missing/implausible signal type stuff, will give them a scan again & clarify

    Thanks again mate :thumbup:
     
  12. Sverre Lervik New Member

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    Hello.

    Im have a golf mk1 where I mounting a mk4 1.9 tdi PD engine. Can you comfirm that i have this correct or not

    My Brown T6

    Pin1 black/purple - ignition
    Pin2 purple/white- glow plug relay trigger
    Pin3 red-starter
    Pin4 red/purple- permanent+ (from battery with fuse)
    Pin5 yellow/black- pin 87 ecu relay
    Pin6 blu/yellow- pin 87 ecu relay

    T14a
    Pin 6- black/yellow pin 87 ecu relay

    Is this far away from correct?

    Thanks
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    wow, that is totally not the way I would do it. no wonder you have warning lights :lol:

    so what I would do is pull the whole loom out and start again. strip out all the polo remains and re-wire the 20v ecu to the polo feeds as above then everything should work properly. The VSS output comes from the cluster, I've highlighted it in the pin list above. basically speed signal comes from gearbox to cluster, then cluster outputs a signal to the ecu.

    I'm really struggling to understand the logic as there is no need to keep the polo ecu at all, immobiliser side is obviously fine otherwise the car wouldn't run and even if the 20v immob was active no way the polo ecu could do anything about that...
     
  14. rubjonny

    rubjonny Administrator Staff Member Admin

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    You have to keep your wits about you, and read my notes carefully for diesels. I might make a separate list as it can be a little too confusing!

    T6
    1 - black/purple - ignition
    2 - purple/white - glow plug relay trigger
    3 - red-starter
    4 - red/purple - pin 87 ecu relay
    5 - yellow/black - pin 87 ecu relay
    6 - blue/yellow - pin 87 ecu relay

    T10h
    8 - blue/yellow - ecu relay earth trigger to pin 85

    T14a
    6 - black/yellow pin 87 ecu relay
    10 - blk/grn - x-relay live to ecu pin 88

    T6 pin 6 may not be in use, depends on equipment. it feeds the ignition trigger side for the extra glowplugs in the side flange to help boost heater output plus breather heater. you dont technically need to run this from the ecu relay, a good ignition live will do just as well its only fed off a 10a fuse. this fuse also does the ignition live for the clutch and brake switches too, could use G2/4 for this for example on CE2
     
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  15. Sverre Lervik New Member

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    Thanks Jubronny

    Im not so far away from the correct then

    T14a
    I dont have pin 10 on my engine harness

    I have reading your post many times, it could bee little confisung some times But its very good I wanted too ask you about the power to ecu, its important too get this correct.
     
  16. rubjonny

    rubjonny Administrator Staff Member Admin

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    what engine code is the PD? on my diagrams T14a/10 is connected to ecu pin 88.

    Or if you mean the donor t14a plug chopped from another car this pin is often unused, you'll have to add a pin if its there on the main PD sensor harness
     
  17. Sverre Lervik New Member

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    My engine AJM. All harness coming from this engine and the same car. Pin 10 on T14a from det engine harness are blended with plug. Never been any wire there.
     
  18. rubjonny

    rubjonny Administrator Staff Member Admin

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    still showing here for your code, is there anything in ecu pin 88? perhaps its only for certain models
    Clipboard01.jpg
     
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  19. Sverre Lervik New Member

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    I will check pin 88 later and let you know. It can bee on certain models as you say. If I remeber correct I think it was a black/green wire on pin10 on the other side of the plug, but not on the engine side.
     
  20. Sverre Lervik New Member

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    Hi.

    Im little confused, where can I take the fuel pump relay trigger signal from? T10w/7 pin is empty on the car side of harness. But from the ECU there is a purple/yellow wire. Can I just add a wire to T10w/7?

    On your Mk4 Diesel engine notes you write relay trigger connection like this:

    85- glowplug trigger T10w/7 or fuel trigger T6/2 or T10/3.

    Are T6/2 trigger for fuel and glow plugs?

    I have a 409 fuel pump relay. How do i connect the relay for the fuel pump?
     

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