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PLEASE HELP... it won't start!!

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by demus, Jun 2, 2012.

  1. demus
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    demus Member

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    Hi all,

    I'm really hoping someone can help here,

    Just went to the car last night and its refusing to start, it ran shortly thursday night perfectly.. Its a 2001 A4 TDI, AWX engine.

    It will crank fine for as long as you hold the key, there are no warning lights, immobilser light is off, and everything looks normal. It seems as if it not opening any injectors. I've checked for fuel at the filter and there is plenty, the pump runs shortly when the key is first switched on as it normally does.. all fuses look ok too ( on the end of the dash ).

    Any ideas anyone as I could do without a trip to the dealers right now, are there any relays that control power for the injectors or anything like that, I haven't tried disconnecting the battery yet, not sure if there was any point or not..

    Thanks in advance for the help,

    Mark
    2001 A4 TDI 130 SE saloon
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  2. SL11CKK
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    SL11CKK Member

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    I believe there is a relay for the fuel pump. However it would greatly help if you plug in the computer.
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  3. stu_m
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    stu_m Active Member

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    You could check the anti shudder valve isn't stuck shut which will cut all air

    It's near the egr valve on the air intake little black thing with a vac line attached
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  4. demus
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    demus Member

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    Unfortunately I don't have access to any diagnostics without towing it somewhere.

    The Haynes I have is next to useless for wiring diagrams for the engine so I'm working in the dark really, everything seems normal, cranks fine, no warning lights, anti-shudder valve is open, fuel seems ok.

    Is there a way to check the fuel pump on the end of the camshaft without removing the top cover to make sure its getting to the injectors?? Or any elecrical things that commonly go wrong that I can check out, or if anyone knows the pin numbers or wire colours for the injectors at the ECU. so I can see if they firing?

    I have just seviced the car too as normal, oil and fuel filters, filled the fuel filter and cycled the ignition a couple of times to purge fuel through. The car ran perfectly afterwards ready to come out the following day. There are a couple of glow plugs down as it was slightly lumpy at startup during the winter, since it has been warm it starts perfectly in the mornings with no smoke at all.

    It ran too perfectly the evening before for me to think its anything serious... I hope!!

    Any more suggestions please, I'd love it to be running again before I need it on Wednesday..

    Cheers guys
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  5. stu_m
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    stu_m Active Member

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    Battery fully charged? I've heard of some people having problems with not starting due to engine not been spun over quick enough

    Apart from that its a plug in job to check for faults etc
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  6. pauldazzle
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    pauldazzle Member

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    Yep won't start if it isn't turning over quick enough. There's a relay 109 under the dash (drivers side ) which will stop the car starting if it's died. VCDS diagnostics needed really as it could be many things stopping it from firing up..
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  7. demus
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    demus Member

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    Cheers guys,

    Its definately turning over quick enough, I'll get out to it later and check out that relay, I guess there is a crankshaft sensor, could this be at fault??

    Has anyone had any experience of this fault code reader, or will I need a more in depth diagnostic?
    Fault Code Reader for Volkswagen, Audi, Seat, Skoda (1996-2009)

    Thanks...
    #7
  8. pauldazzle
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    pauldazzle Member

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    I'm not completely sure relay 109 is under the drivers side dash on Audi's. Thats where it is on VW Golf/Bora, & Skoda Octavia, but Audi does tend to do things differently to the rest of VAG. If you have a Haynes book of lies that may help.
    Most code readers don't actually recognise all VAG DTC's. You are much better off buying a VAG OBDII cable off ebay, & downloading the free VCDS lite from the Ross Tech
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  9. marktdisport
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    marktdisport Active Member

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    am i right in thinking that the car was running perfect and then you serviced it then parked it up !!! if so check around the fuel filter again as if its not sealed right cud be sucking in air and also cause fuel to drain back as if they do run dry on fuel they can be a ***** to prime up even though they should prime themselves ?? someone in a previous thread also had trouble the day after and it just took loads of cranking and throttle and eventually it fired up... also check the fuel filter as got fuel in it will give you a indication to see if its fuel filter related or somethink further up the line
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  10. demus
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    demus Member

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  11. gen.heinz guderian
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    gen.heinz guderian Active Member Regional Rep

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    I can scan it for you im in Loddon , so only 20-30 mins away, can come to you tomorrow (monday)
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  12. marktdisport
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    marktdisport Active Member

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    1 of my neighbours recently had a prob after he serviced is ford focus diesel on the drive he could not get it going.... i was out at the time and when i pulled up they was towing it up the road.. as they'd been trying for hours to get it running.... aint to sure why but i went straight away from a tow and been perfect since... i thought hed put the pipes on the filter wrong... take it youve swopped like for like
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  13. quattro tony
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    quattro tony Member

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    Sounds like air in the fuel system, especially if you have just serviced it, I personally find turning the ignition on and off a couple of times is not enough, Once you get air in the system it can take a fair bit of cranking to get it going again, turning the ignition on and off a few more times can help. I always like to fill the fuel filter manually when i do them to save on problems like this . How long did you run the engine after you put the fuel filter on and started it up? I would certainly check your basics first before you go diving into diagnostics, etc.......It is worth checking the air flap next to the egr, quick and easy to do.
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  14. demus
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    demus Member

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    Tony,

    It probably ran for 2 mins max I reckon, started easily with smooth idle, the filter seems full of fuel, if I remove the outward pipe and flick on the ignition fuel comes out pretty quick, cant check the pipe from the second pump on the camshaft easily without fuel flying everywhere. The return hose connection on the filter T seems to have a good hold didnt want to break it.

    Maybe air in the second pump, the car has in all fairness been fine with no signs of dying!!

    Air flap is open too...
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  15. pauldazzle
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    pauldazzle Member

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    Running at idle for 2 mins if you didn't prime the fuel filter wouldn't have cleared an air lock.
    There was another post recently with exactly the same problem after servicing, & that was air in the system.
    That OBDII cable on ebay should be fine by the way.
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  16. demus
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    demus Member

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    Turns out it was air trapped in the tandem pump up on the camshaft, got some air out initially then gave it another good crank and it coughed, cranked again and it fired up.... So a 2 minute run after changing the fuel filter isnt enough for sure, didnt give it much thought but I must have run it for longer the last times I changed it.
    Will get the diagnostics anyway in case for the future.....

    Thanks for the help everyone.. much appreciated..
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  17. pauldazzle
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    pauldazzle Member

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    Good stuff. VCDS is well worth having, & much better than a code reader.:applaus:
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