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Thread: Polo 9N 2004 1.2 wont start, possible fuel pump issue

  1. #1
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    Polo 9N 2004 1.2 wont start, possible fuel pump issue

    Hi all,

    Not having much luck with Polo's this month. My girlfriends polo decided not to start this morning. It cranks fine but won't fire up.
    I decided to check the fuel pump even through I think it can hear the pump priming but something felt odd.

    So I unplugged the hose that was going into the fuel rail and placed it in a bottle to see how much petrol comes out:
    Click image for larger version. 

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    Turned the ignition on and nothing happened, I tried 4 or 5 times but only few drops of petrol came out. I assume I tested the right hose?
    What should I check next?

    [Update]
    Ok fuel pump does work I tried with when cranking and lots of petrol was coming out I also took out the rail to see if the injectors are working and yep they were spraying as the engine was cranking. I checked all the spark plugs and there was very bright spark in all 3 so it has air and fuel and spark which I am super worried that the timing might be shot

    BUT it's a chain and not belt thus I thought it wouldn't skip and throw the timing off?

    Thanks.
    Last edited by John24; 16-12-18 at 12:35.
    2000 Polo 6N2 1.0, Petrol
    G/F: 2004 Polo 1.2, Petrol

  2. #2
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    There's a shrader type bleed valve at the other end of the fuel rail under that blue cap. might be an easier way to see if fuel pressure is building at appropriate times.

    I'm just off out unfortunately, but check fuses in case one for e.g. ECU relay or something has popped. Can check wiring diagrams later to be more specific.
    My car: 2003 Polo 1.4 BBY, Petrol
    Good Lady's: 2005 Mk1 Skoda Fabia 1.2, AZQ

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    [Update]
    Ok fuel pump does work i tried with when cranking and lots of petrol was coming out I also took out the rail to see if the injectors are working and yep they were spraying as the engine was cranking. I checked all the spark plugs and there was very bright spark in all 3 so it has air and fuel and spark which I am super worried that the timing might be shot

    BUT it's a chain and not belt thus I thought it wouldn't skip and throw the timing off?
    2000 Polo 6N2 1.0, Petrol
    G/F: 2004 Polo 1.2, Petrol

  4. #4
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    If it's a 12 valve you can check the chain timing by taking the end covers off the cams and looking at the slots that the locking tools fit into. They should be at the same "o'clock" relative to each other; and if you put the engine to tdc they should align with each other.

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    Quote Originally Posted by Pete1 View Post
    If it's a 12 valve you can check the chain timing by taking the end covers off the cams and looking at the slots that the locking tools fit into. They should be at the same "o'clock" relative to each other; and if you put the engine to tdc they should align with each other.
    Yep there two covers on the cam and I took them off and both align and point the same direction. I am not sure what to do next?
    I have not checked compression yet but I did check it 4 months ago:
    Cylinder #1 - 162 PSI
    Cylinder #2 - 175 PSI
    Cylinder #3 - 174 PSI

    Any ideas what to check next?
    2000 Polo 6N2 1.0, Petrol
    G/F: 2004 Polo 1.2, Petrol

  6. #6
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    These engines are VERY prone to jumping their timing chains, you need a locking tool set from Laser or AST. With you cranking the engine with the plugs out and in the coil packs, be extremely carefull to make sure the plug is well earthed, cranking them over unearthed makes them fail.
    2003 Skoda Octavia VRS Estate. APR 98RON remap, APR R1 diverter valve, Jetex exhaust, K&N panel filter, 7.5x18 Alutec Monstr wheels with 225/40 18 Uniroyal Rainsport 3 tyres.
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  7. #7
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    Well I have checked the compression and it's not good
    Cylinder #1 - 70 PSI
    Cylinder #2 - 110 PSI
    Cylinder #3 - 75 PSI

    I put some oil in Cylinder #2 and got 250 PSI, so it seems that piston rings are gone
    2000 Polo 6N2 1.0, Petrol
    G/F: 2004 Polo 1.2, Petrol

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    Or bore wash from many failed attempts to start it?

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    Quote Originally Posted by Pete1 View Post
    Or bore wash from many failed attempts to start it?
    Actually the car has been having issues with the error code coming up "fuel mixture too rich" but I couldn't track down the issue. So you think the cylinder walls are gone?
    2000 Polo 6N2 1.0, Petrol
    G/F: 2004 Polo 1.2, Petrol

  10. #10
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    I think temporarily, the oil film that helps the rings seal may have been washed away by excess petrol during failed start attempts.

    Not sure what you can do about it other than try to spray a little oil in through the other plug holes too, but that wouldn't necessarily solve the non-start situation, but worth a try just in case it does?

    Seems really unlikely to me that rings could fail in all three cylinders suddenly.

    Crank sensor?

    I'd offer to plug in my VCDS for a look at things if I thought you were near?
    My car: 2003 Polo 1.4 BBY, Petrol
    Good Lady's: 2005 Mk1 Skoda Fabia 1.2, AZQ

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