MK2 GTI 20v Home build - Putting it back together

Discussion in 'Members Gallery' started by cupracraig, Mar 5, 2018.

  1. Vinnie

    Vinnie Paid Member Paid Member

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    Coolant sensor goes faulty it over fuels. should be able to see the temp on you obd reader think they end up going -20 on the reading
     
  2. cupracraig

    cupracraig Paid Member Paid Member

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    I think I might have found the issue. I have an earth connection mid way between the loom connection and the fuel pump relay. So I think that might have been causing issues. Have labelled it and will plug the loom back in tonight to check if that solves the problem
     
  3. Vinnie

    Vinnie Paid Member Paid Member

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    Hope so mate.small things always the biggest problem it seems.
     
  4. cupracraig

    cupracraig Paid Member Paid Member

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    I have edited this post a few times, but now that the engine is up and running, this has everything i need to get my AGU running. Thanks to John Newman AKA RubJonny for the help as always!


    So i have decided to just write out all the connections for the AGU to CE2 here, it will be easier to spot the issue and might also be useful for others:

    I run a separate relay to power the ECU which is a 53 Relay, it is not the prettiest, but it works and its solid.
    [​IMG]



    Z1 - to Engine loom connection pin 5
    30 - to fused ECU relay Pin 30- this then powers ECU pin 3 - so Permanant Live as its a live fed before the relay takes an action?

    relay Pin numbers
    30 - fused Live from Fusebox Live 30
    85 - Earth - Engine loom Pin 9, Earthed near the fusebox
    86 - Goes to G2/4
    87 - Goes to engine loom pin 8 and also ECU Pin 1



    G1/1 - Empty
    G1/2 - outside air temp sender ground
    G1/3 - ECU relay power to ECU pin 4
    G1/4 - Empty
    G1/5 - Ground to Cylinder Head
    G1/6 - Empty
    G1/7 - Empty
    G1/8 - Heated Oxygen sensor power - this merges into a single feed for my MAF and O2 sensor power and engine loom pin 6
    G1/9 - Empty
    G1/10 - Empty
    G1/11 - Blank
    G1/12 - Tacho input

    G2/1 - Oil Temp (to a sender on the oil cooler/filter housing part number 049919563B)
    G2/2 - Outside Air Temp Sender
    G2/3 - feeds engine loom pin 4 (should be coolant temp sender)
    G2/4 - feeds to ECU relay 86
    G2/5 - Empty
    G2/6 - Empty
    G2/7 - Empty
    G2/8 - Empty
    G2/9 - Empty
    G2/10 - Oil pressure (High Oil Pressure Switch to a sender on the engine (056919081 - oil pressure switch, 1.8bar, white))
    G2/11 - Engine loom pin 1 - (Low Oil Pressure Switch (028919081H - oil pressure switch, 0.24bar, blue ))
    G2/12 - Empty


    T14a connection - Engine loom (agu)
    1 - G2/11 (Low Oil Pressure Switch) - this is a black wire on the engine loom that has goes to a low pressure sender
    2 - Empty
    3 - Empty
    4 - G2/3
    5 - Z1 Power
    6 - G1/8
    7 - Earth for coilpacks - To the battery
    8 - Coilpack Power - to ECU Relay 87, The 87 connection also runs to ECU Pin 1
    9 - ECU relay pin 85 - Its the Earth for the Coolant Temp Sensor, can go to any earth point.
    10 - Empty
    11 - Empty
    12 - Empty
    13 - Empty
    14 - Empty

    ECU connection:
    1- Live from Relay pin 87
    2 - Earth - just needs to be a solid earth point
    3 - Permanent Live relay pin 30
    4 - G1/3
    6 - Tacho - rev signal
    12 - MAF Pin 3
    13 - MAF Pin 1
    19 - Kiline for OBD Port
    25 - 02 sensor
    26 - 02 sensor
    27 - Lambda Earth - can go above fusebox
     
    Last edited: Feb 9, 2021
    erreesse likes this.
  5. Vinnie

    Vinnie Paid Member Paid Member

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    Where about a is the Crank sensor
     
  6. cupracraig

    cupracraig Paid Member Paid Member

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    car was all fine and running when i pulled the loom previously though, can imagine it would just break when laid up?
     
  7. Vinnie

    Vinnie Paid Member Paid Member

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    About right for this year.hope it gets not to much of a pain to find it does it even try to run
     
  8. cupracraig

    cupracraig Paid Member Paid Member

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    yeah on occasion it will for a few seconds. this is why i think its a wiring issue. Bad earths can play a big role in intermittent running
     
  9. cupracraig

    cupracraig Paid Member Paid Member

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    Got some errors on a scan now i can connect to VagCom, maybe my wiring is ok and i just have the issue with the throttle, i knew it was not making the noise like it used to. I did replace the clip for that connection, so likely got a wire the wrong way around?

    17953 butterfly valve control malfunctioning
    17973 butterfly valve control unit -J338 lower notice one does not reach
    00670 - Throttle Position Sensor (G127) 06-00 - Signal too High
    16507 butterfly valve potentiometers signal too largely
     
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  10. Vinnie

    Vinnie Paid Member Paid Member

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    Hope this sorts it mate
     
  11. cupracraig

    cupracraig Paid Member Paid Member

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    throttle body resolved, 2 of the tiny cables were reversed. Now it sounds and acts as expected...

    still no fire up though witht he MAF in...this might be down to none of the pipes being connected up with clamps, just loosly on and loads of VAC leaks..

    With the MAF off, it ran!
     
    Last edited: Dec 5, 2020
  12. cupracraig

    cupracraig Paid Member Paid Member

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    Little update in that with the MAF on today it started up first time
     
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  13. dodgy

    dodgy Paid Member Paid Member

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    Grrr technology!
    Certain gremlins are a nightmare, let's hope its sorted mate.
     
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  14. rubjonny

    rubjonny Administrator Staff Member Admin

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    The ecu relay is your main issue most likely. pin 85 of the relay needs earth. pin 9 on the T14a plug is the earth for the coolant temp sensor.

    Usually you would put the ECU live from one of the Y spades, but if you have a MK3 30-30b jumper this has connections on the back of it. You can also use G2/9, its unfused but isnt a big deal for this feed as its tucked up pretty safe in the loom. If it helps put your mind at rest MK3 and Corrado ECU permanent live is unfused wire from Y spade or G1/9. can also splice a wire direct to the 30-30b jumper if you like will work just fine. More info on ECU live later ;)

    G1/10 is ecu relay feed, not really where you would usually tap your electric windows into. electric window relay trigger should be D plug, 8,9 or 11

    G2/4 is ignition live output, you mention fuel relay 86? did you mean ECU relay, that would make sense ;)

    T14a:
    1 - unused unless running electronic speedometer
    7 - earth for coilpacks -> battery
    8 - coilpack power -> should be fed from an ecu relay along with ECU pin 1. assume typo same as above ;)
    9 - earth for coolant temp sensor, can go to head, battery or chassis all fine

    ecu pin 2 I put to battery just because, but on the MK4 it earths to the chassis near ecu. can earth above fusebox if thats closer, just make sure its a decent earth point.

    ecu pin 27 isnt an ECU earth, its the earth for the lambda probe heater

    For ECU relay, you can run it like this:
    Y spade -> 15a fuse -> ECU relay pin 30 and ECU pin 3
    85 - earth
    86 - ignition live
    87 ECU pin 1, T14a/8

    this is just like the DBW looms are from the factory and means you can use 1 fuse for both the ecu live and coilpacks.
     
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  15. cupracraig

    cupracraig Paid Member Paid Member

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    Yeah ECU relay, not sure why i was calling it the fuel relay. Just confusion i think.

    Thats good info John, thank you again! will updaye my list above. i'm sure i'll need to re-visit it again at some point
     
  16. cupracraig

    cupracraig Paid Member Paid Member

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    Well the car is running reliably so back to wiring and just making that work in terms of routing a little bit better.

    The ecu to engine loom is fine but with the way i wanted to route the ECU relay to engine was a bit short. So i've extended it by about a meter or so, this should give me the slack i need to run it properly.

    Injectors have been swapped over
    Driveshafts in
    Intercooler plumbed in
    Battery relocated to the boot and working
    Live and Earth feeds to the battery to the boot
     
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  17. dodgy

    dodgy Paid Member Paid Member

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    Getting there then Craig, it's all the little bits that take the time, and hiccups along the way dont help at all.
    Keep it up mate.
     
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  18. cupracraig

    cupracraig Paid Member Paid Member

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    Been doing some bits but forgot to take many photos.

    Fusebox to engine loom extended just to make it all much easier to route internally.
    Engine loom looks much tidier now
    Battery cables ran but will need to decide on a new battery and how i'm going to secure it in the boot... i have got a false floor in there at the moment for the Sub, but i won't be running a stereo any more, so might re-make the floor and secure the battery to that.

    [​IMG]IMG_20201218_145924 by Laxadams, on Flickr

    [​IMG]IMG_20201218_151432 by Laxadams, on Flickr

    [​IMG]IMG_20201217_160620_758 by Laxadams, on Flickr
     
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  19. Savagesam

    Savagesam Moderator Staff Member Moderator

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    Looks very tidy. Nice!
     
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  20. cupracraig

    cupracraig Paid Member Paid Member

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    Modified the TIP, MAF and intake

    [​IMG]
     
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