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Help me fix this 1.8t that is driving me insane!

Discussion in 'A3/S3 Forum (8L Chassis)' started by Lingo89, Dec 8, 2012.

  1. Lingo89
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    Lingo89 Member

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    [Dec 8, 2012]
    Okay, so following on from the last thread I created relating to my AUM 1.8t not starting/ starting and then running like ****, I have changed the MAP sensor for a brand new one. This has still not solved my problems. The car will turn over and it will sound like it wants to start and then it just won't, with enough effort it will eventually start and idle but if you rev the car, the engine dies and turns off.

    I did an initial VCDS scan following on from fitting the new MAP sensor on and I get the following errors:

    --------------------------------------------------------------------------------
    --------------------------------------------------------------------------------


    5 Faults Found

    16621 - Manifold Pressure / Boost Sensor (G31): Signal too Low
    P0237 - 35-00 - -
    16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal
    P0106 - 35-00 - -
    16727 - Camshaft Position Sensor (G40): Signal too High
    P0343 - 35-00 - -
    18041 - Accelerator Position Sensor 2 (G185): Signal too Low
    P1633 - 35-00 - -
    16497 - Intake Air Temp. Sensor (G42): Signal too High
    P0113 - 35-10 - - - Intermittent

    I then cleared all the faults and this one fault always returns immediately as soon as I clear them, the car doesn't need to be turned over at all. The fault just returns as soon as I clear:


    1 Fault Found
    1 - Manifold Pressure / Boost Sensor (G31): Signal too Low
    P0237 - 35-00 - -

    If anyone has a clue as to what's going on here please give me some advice as I am losing my wits here! alternatively if no one has the knowledge to help, can anyone recommend me a very good an Audi/VAG 1.8t specialist who will be able to help me in the Essex/ East London area?

    Cheers in advance for any helpful replies!
    Last edited: Dec 8, 2012
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  3. Alex C
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    Alex C Well-Known Member

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    [Dec 8, 2012]
    is this: AUM engine, AUM ECU and AUM wiring loom?
    #2
  4. Lingo89
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    Lingo89 Member

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    [Dec 8, 2012]
    It all is indeed AUM. AUM engine, AUM ECU and AUM engine loom.

    I'm unsure as to how related the issues are but I should probably add this:

    I've recently found this pipe at the back of engine bay that is disconnected and I have no idea where it's supposed to connect or if it should be connected at all!

    The pipe looks like this on the top of the engine bay:

    [​IMG]

    I took a picture from underneath the car to determine where it comes from by the turbo:

    [​IMG]

    Finally, can anyone confirm the N75 valve is plumbed correctly? I don't see why it wouldn't be as even though this is a 1.6 to 1.8 turbo engine conversion I have not touched/ changed how this was all plumbed originally:

    [​IMG]
    #3
  5. Alex C
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    Alex C Well-Known Member

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    [Dec 8, 2012]
    could the disconnected pipe be the return from the charcoal canister? Also looking at Elsawin G31, 40 & 42 share a common Earth point within the wiring loom described as - sender Earth. No idea what that means
    #4
  6. A3-Lee
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    A3-Lee Active Member

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    [Dec 8, 2012]
    That's the pipe for the charcoal canister mate if you have done the evap delete this can just be blanked off
    #5
  7. Lingo89
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    Lingo89 Member

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    [Dec 9, 2012]
    Okay, so thanks to all your help I've managed to get that pipe reconnected but unfortunately that is not the root of my car's problems! It still won't start properly. Alex C do you know where this sender earth location is? perhaps the wiring is my issue...
    #6
  8. A3-Lee
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    A3-Lee Active Member

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    [Dec 9, 2012]
    Is the car a 1.8t conversion? I'd check all your earths and all connections to start with check you have a spark and fuel and go from there is the best bet sometimes I find going back to basics the best way mate I can imagine how frustrating it must be for you good luck
    #7
  9. woody.dub
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    woody.dub Member

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    [Dec 9, 2012]
    Where abouts in Essex are you mate
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  10. smiler2012
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    smiler2012 Member

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    [Dec 9, 2012]
    that fault 16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal is an apsalute night mare could be the throttle body needs cleaning most common fault for that to show means that there is an air leak? These commonly leak from the inlet manifold you can here a hissing sound there are 2x pipes under neath that split you need to check them out? also 16727 - Camshaft Position Sensor (G40): Signal too High this could be a faulty camshaft positioning sensor which would give you hard starting and also that could be a timing fault? timing may have jumped causing hard starting and running rough hope this helps?
    #9
  11. Alex C
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    Alex C Well-Known Member

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    [Dec 9, 2012]
    elsawin says its in the wiring harness - not much help i know. Sorry

    Have you cleared the fault codes and rechecked if you still have your G71 fault code - may have been caused by your charcoal canister pipe work not being connected?
    #10
  12. Lingo89
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    Lingo89 Member

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    [Dec 23, 2012]
    Hey guys, I've cleaned the earth connections on the body behind the headlight that sit underneath the body and this has miraculously made starting the car easier (it will start second time every time. The car even runs better but it is certainly still lacking power, it's almost as if the clutch is slipping sometimes but that's definitely not the issue, it's just not producing the power under load that it should, I've posted a video to highlight the problem.


    In both runs I am giving the car full revs, notice how the second time the car lacks mid-range revs:


    VID 20121118 00006 - YouTube


    Given the car another run through VCDS after clearing all the faults and this is what comes up. It has me quite baffled, I'm thinking perhaps the camshaft sensor is faulty? one thing that always comes back straight after clearing even before the engine starts up is the G31 sensor warning:




    7 Faults Found


    16621 - Manifold Pressure / Boost Sensor (G31): Signal too Low
    P0237 - 35-00 - -
    16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal
    P0106 - 35-00 - -
    16727 - Camshaft Position Sensor (G40): Signal too High
    P0343 - 35-00 - -
    18041 - Accelerator Position Sensor 2 (G185): Signal too Low
    P1633 - 35-00 - -
    16486 - Mass Air Flow Sensor (G70): Signal too Low
    P0102 - 35-00 - -
    16705 - Engine Speed Sensor (G28): Implausible Signal
    P0321 - 35-10 - - - Intermittent
    16885 - Vehicle Speed Sensor: Implausible Signal
    P0501 - 35-00 - -
    #11

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