1.8t wiring

Discussion in 'Say 'hello' in here.' started by Kevcaddy, Jan 9, 2022.

  1. Kevcaddy New Member

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    Hi I’m new to here and have posted a couple of things trying to get intouch with rubjonny but don’t seem to be getting any reply’s
     
  2. rubjonny

    rubjonny Administrator Staff Member Admin

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    you posted on my personal wall on saturday, have some patience I dont work weekends ;) just replied to you in my mk4 conversion thread
     
  3. Kevcaddy New Member

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    Hi sorry new to this, I managed to get it running and revving yesterday, I had to unplug coolant temp sensor, so replaced it still same, so I unplugged map sensor and it revs and idles with cts plugging in, the one thing that happens is if I connect the blue/yellow wire off the maf to positive it just dies
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    No worries :) get vagcom plugged in and scan it for faults, clear them and run it again see what comes back. you can check through the ecu measuring blocks to see all the sensor inputs in real time also. could be maf is bad, you can check airflow grams per second in the blocks, also worth looking at inlet and coolant temps, throttle position etc
     
  5. Kevcaddy New Member

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    Also the pre cat lamba is wired in but don’t know what to wire no3 pin to on the plug blue/red, say fuel pump relay?
    hi the codes I have are p1548,p1118,p1531,p1287,it will start but bog out, I can get it to Rev sort of then if I go to pull off it just bogs out, then if I try and restart it I get a starter motor noise then restarts,just don’t get it thank you, I’m sure it’s a wire or it’s loosing its fuel pump or spark
     
  6. Kevcaddy New Member

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    The more I think about it the more I think the problem is around the 428 relay not doing it full job
     
  7. rubjonny

    rubjonny Administrator Staff Member Admin

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    p1548 - Boost Pressure Controle Valve (N75): Open Circuit
    p1118 - Oxygen (Lambda) Sensor Heating; B1 S2: Open Circuit
    p1531 - Camshaft Timing Adjustment: Open Circuit
    p1287 - Boost Pressure Control Valve (N249): Open Circuit

    if those come back look at your power feeds to all of the above. They are fed by the T14a/6 pin except for the lambda heaters which are powered by the same feed that does the maf heater from T6/5. tbh sounds like your loom needs going back over

    all of the above are fed from fuel relay power originally, but ignition live would also work
     
  8. Kevcaddy New Member

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    Ok well I found the main problem (I hadn’t put the tt fuel pump in the tank ) starts and revs perfect but if I go to pull of it bogs out still get p1548 and p1531 1287, ive used the original caddy fuel relay
     
  9. rubjonny

    rubjonny Administrator Staff Member Admin

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    check for 12v at those 3 valves when engine is running, if nothing go to the t14a/6 and chase back to where you spliced it
     
  10. Kevcaddy New Member

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    Ok so I started the van today had it running and check those 2 sensors and have got 14.something volts, check diag again no faults, does pin 6 of t14a Need perm live or ignition? Also I think the bogging out is because I haven’t set up gearlinkage right so it’s selecting 3rd instead of 1st(what a plonker I am) thanks for you help mate
     
  11. Kevcaddy New Member

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    So gone up the road today and it’s blew the rear boost pipe off again, plugged it in again and still getting n75 fault and inlet camshaft fault, but the plugs are showing 14v running? What could it be thanks
     
  12. Kevcaddy New Member

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    hi mate done my checks on the two sensors,n75 & vvt cam senor ,

    N75 =0.29 ohms

    Yellow /blk wire 14.3v

    Green/red 3.52


    Vvt 0.16ohms

    Yellow/blk 13.9v

    White/green 5.8v


    All is while running, if I drive it up the road it just comes on to boost and misfires, if I unplug these sensors it drives fine with minimal boost,

    What do you reckon, could it be the map? When I put my probe to the green/red wire it came negative but flashing while running
     
  13. rubjonny

    rubjonny Administrator Staff Member Admin

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    pin 6 needs ignition or fuel relay power, but you have power at them so is all fine. both of those the other pin is pulsed to earth by the ecu so what you saw was correct when you probed.

    whats the full code coming back for all of those, may not be open circuit could be something else. ideally vagcom/vcds is what you want will tell you a bit more
     
  14. Kevcaddy New Member

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    Ive decided to take engine loom back out and strip it back to see if any broken wires as I’ve changed all the sensors and still getting the same codes
     
  15. Mk2daz

    Mk2daz Paid Member Paid Member

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    did you clear the codes after changing the sensors? As they won't clear themselves just from changing sensors.

    Good idea to go right over the loom though for piece of mind anyway!
     
  16. Kevcaddy New Member

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    Yes I cleared them
     
  17. Kevcaddy New Member

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  18. Kevcaddy New Member

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    I have taken engine loom out and stripped it back, no broken wires and continuity on all wires, could it be on the power side of the loom?I just really don’t get it, and I get wierd starter noise after it’s been running and restarted, then these faults re appear
     
  19. rubjonny

    rubjonny Administrator Staff Member Admin

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    hmm, check the feed to t14a/6 on the car side next, maybe an issue there
     
  20. Kevcaddy New Member

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    Ive run it to ign live, i havnt used nothing on the caddy t14 plug
     

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