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Trouble Starting - 1.8T (Not your average!)

Discussion in 'A3/S3 Forum (8L Chassis)' started by 1.8TAGU, Mar 5, 2009.

  1. 1.8TAGU
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    1.8TAGU New Member

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    Ok, so i have done a search and read loads of threads but none which seem to match up with the problems i'm having! I'll be as detailed as possible....

    Went on a 35-40min drive to a meeting... when i got there, meeting had been delayed so i jumped back into the car and drove 2minutes to the shop. Came out of the shop, turned the key, the car started for a split second and died.

    There was about a 1/4 tank of petrol, but it was parked on a hill so I called the brother around and we got another 5litres and still no joy. I noticed then that the pump wasn't trying to prime when i turned the key. Out with the tow rope, and back towards home. BUT, after 5 or 6 mins towing, i tried to start the car and it fired up... drove home from there with zero problems, running fine.

    The following day i started it up to let someone out of the driveway, put the car back in and it hasn't started since. The fuel pump is not priming. I got a pump from the breakers, and it still didn't prime. I then got a brand new pump, still no prime. I didn't install the new pump fully, i just put the power wire on it to see if it was going to try prime.

    I also got a brand new key from Audi, coded to the immob, and it made no difference.

    I also got a new fuel pump relay from Audi, and a crankshaft sensor. Neither did the trick.

    It's definitely not getting fuel, as i have removed the fuel lines from the rail and they're bone dry.

    VAGCOM shows no errors, although the last time i hooked it up was before i put the new crankshaft sensor.... would i have to clear any faults or anything for that to work?

    Anyone have any ideas as to what to do next?
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  2. HTC
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    HTC Active Member

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    What year is it? Some models should prime if the door is opened.

    If the relay has been changed, have you check power and feed to it? Does it click at all? Have you checked the fuse. Also the fuses on top of the battery and associated connections? Are all other electronics working. Ignition switch okay?
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  3. 1.8TAGU
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    1.8TAGU New Member

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    It's a mid-1998 model. I've not noticed it priming with the door open before, although now that you say that, i have had trouble with the door drooping and i had been messing with that a few days previous to this happening. May or may not have had something to do with it.

    Aswel, i probably should have mentioned that the distribution block was fried. Litterally melted with a few scorch marks. I got a new one, and tested all the wires going from it - they're fine. All the fuses seem to be fine too.

    How can i test the ignition switch? All the warning lights seem to be working fine, the car cranks as normal, but just doesnt catch - due to the lack of fuel.

    Is there a way i can power the fuel pump independantly to the car?
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  4. HTC
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    HTC Active Member

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    That year won't prime with the door, so don't worry about that.

    Yes you can run the pump independantly. I've done it to trouble shoot in the past. How are your wiring skills? Would be a good check to test if it's just that circuit or something else. Do a search for fuel outlet tests on here I posted a how-to that describes how to turn the pump on. You need to get involved in the wiring diagrams to trace properly.

    To test the ignition switch, pull off the cowling and get a test light or multimeter on it.
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  5. 1.8TAGU
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    1.8TAGU New Member

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    I have the multimeter here now to do some investigating.

    Do you know off the top of your head which wires correspond to the pump and which control the sender?
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  6. 1.8TAGU
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    1.8TAGU New Member

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    Just noticed there that if i leave the ignition on for 20 seconds or so, i get a constant beep with the coolant symbol flashing. Could any fault relating to this stop the fuel from pumping?
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  7. HTC
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    HTC Active Member

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    Break things up a bit.

    Is the pump okay? Yes beacuse you've swapped it.
    Is the wiring to the pump okay? Do a continuity test.
    Is the relay okay? Yes, you've swapped it.
    Is there power to the relay? Turn the ignition on and see if you have switched live at any of the contacts. If it makes a click then yes, if not then probably no. But test with the multimeter.
    Pump earth and relay earth okay? Check.

    There is an ECU feed, but I can't remember the wiring colour. It's the same as MK4 golfs so you could take a look at a haynes manual or search online for the diagram. I'm sure someone has poseted them before. Even without that feed it should prime at least once.
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  8. 1.8TAGU
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    1.8TAGU New Member

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    Ok, so i think i have come to a conclusion (kind of).

    I wasn't getting any voltage when testing the fuel pump connector, but i pierced the blue wire about 2cm up from the connector and got 12v on turning the key. It was getting dark so i couldn't do anything else about it.

    How will i change the connector?

    I got one with the pump i got from the breakers.. instead of taking the connector off, they just snipped the wires. Could i cut off the existing connector, expose the wires and join them? Wrapping in electrical tape to seal? I can't see any way to take apart the connector without breaking it....
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  9. 1.8TAGU
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    1.8TAGU New Member

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    Ok, some more problems on this.

    I've discovered (with the help of a test light) that there is not power at the fuel pump fuse. When i touch the relay when putting the key to 'IGN' - it definitely opens.

    If anyone has any ideas before i call on the auto-electrician - shout now!
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