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2.5tdi starting issue

Discussion in 'A4/S4 forum(B5 Chassis)' started by mat_vw, Feb 24, 2010.

  1. mat_vw
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    mat_vw Member

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    Hi

    I need a little help quite new to this engine,
    In the mornings when the engine is cold turn ignition on wait for the glow plug light to go out then i turn the key then it cranks for about 15-20 sec before it springs into life.

    So my question is there a fuel run off valve, which is allowing the fuel from the pump to go back to the fuel tank which in turn is taking the car long to start because it has to suck the fuel from the tank every morning.

    Also a diffrent issue heater fan is playing up i have done my research on this and i have had to glove box off and undone the screws on the fan but there is a metal plate that is stopping me get the fan out which looks like it connected to the passanger airbag which i dont facy removing.

    So my question is that metal plate easy to remove any links would be great.

    Sorry for the long winded post, i am new to this car.

    Any help would be apreciated. Many Thanks Mat. :icon_thumright:
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  2. Mike B
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    Mike B Member

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    Try checking the spill pipes from the injectors.Ive heard that starting problems can be caused by leaks or cracked pipes allowing air into the system.I amchanging mine to see if it helps.Just finished one bank and and will look at the other side at the weekend
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  3. mat_vw
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    mat_vw Member

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    Cheers for that, what do spill pipes look like, are you on about the pipe from the pump to the injector.
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  4. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    Have you had the car codes read at all on VAGcom or similar?

    I don't want to scare you but there is an issue with pumps on these models..
    #4
  5. mat_vw
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    mat_vw Member

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    No i have not had any code read yet, i will get that done. Been doing a bit of looking about and i am going to replace the temp sensor and glow plug relay, all glow plugs have been replaced.

    At lunch today i had a quick look to see if i could see these spill pipe, the image below has two arrows the first being the rocker cover covered in diesel and the 2nd arrow indicating the spill pipe (i think) which is socked in diesel these need to be replaced but i need to pull on off to see what size they are fist.
    [​IMG]

    Could someone tell me if the 2nd arrow is pointing to the spill pipe and this would indecate that there is a posiblility of air getting into the fuel. I hope it not the injector leaking. Mat. :crying:
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  6. diffas
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    diffas Member

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    That's the returning line. If that leaks change it. Most likely air is coming from fuel filter (O-ring).
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  7. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Yeh "2nd" points at the spill lines, thats quite likely to be the problem!
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  8. mat_vw
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    mat_vw Member

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    Update:

    I have had it read for fault codes and there is nothing, checked all glow plug and there is power to all of them so there fine. All fuse in engine bay are fine. Ordered new temp sensor from audi, audi say there is not glow plug relay which i find strange unless it is intergrated into anther relay could someone confirm this.

    Got some new return line to replace leaking need to get some more to redo the whole lot, go down local parts place tomorrow.

    So hopefully by monday it will start better once temp sensor has been fitted. Hopefully. Otherwise the only thing left to do is get the timing checked unless anyone has any more ideas.

    Cheers Mat.
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  9. Mike B
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    Mike B Member

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    The spill pipes will probably help mine seems to have improved.They are standard braided types but atight fit . Do you think the new sensor will help starting?My sons 2.5 is not good at warm starting and seems poor on mpg and he is thinking that it could be the sensor because his pipes show no leaks.
    #9
  10. adamss24
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    adamss24 Well-Known Member

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    Relay 202(BLUE ) is the glow plug relay. Every diesel engine has it from 1996 onwards !
    #10
  11. mat_vw
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    mat_vw Member

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    I will be able to tell you later tonight if the sensor makes any inprovement that if audi manage to get it in. what i have done is there are four wires coming off the temp sensor i have cut one the brown one nearest to the front of the car, make the car think it always cold outside so glow plug lights stays on for a while but still give coolent temp reading to dash and ecu, takes fewer cranks to get it started that way. Thats what makes me think it something to do with the temp sensor because if it connected just take forever to start. I will get photo later.
    Last edited: Mar 3, 2010
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  12. mat_vw
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    mat_vw Member

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    Replaced the sensor, it starts a little better, but when it is hot takes 4-6 tries to get it started so i think my best bet is to bite the bullet and put it into a garage, to get the issue sorted, hopefully they will be able to check the fuel pump timing as they are a diesel specalist and they have the lastest diagnotic equipment. I just dont want to leave it like it is just in case i causes any other issues.
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  13. Mike B
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    Mike B Member

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    We are thinking that it could be the battery cos a new one has done it for others.Is yours 100%?We will try a good recharge first and possibly renew if it seems to work
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  14. mat_vw
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    mat_vw Member

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    That sounds like a good idea, because first thing in the morning starting it sounds like it struggles on the first key turn, then on the second key turn it sound much more alive, i will fully charge the battery later.

    When the water temp is around the 60c mark it always fires up first time not matter what. But when it closer to the 90c mark it just embarrassing, cranging all the time, Mike B do you seem to have the same issue.
    Last edited: Mar 10, 2010
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  15. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Does the actual coolant temperature reading in vagcom match the dash?
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  16. mat_vw
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    mat_vw Member

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    Battery is fine nothing wrong with that, as soon as i can get a copy of vagcom i will check the temp reading.
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  17. mat_vw
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    mat_vw Member

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    I know it been a while since i have posted on this, but i have only worked out what the issue was, it was air leaking into the fuel system from one of the rubber tubes connected to the fuel filter, only worked this out since i changed it.

    Now start fine when hot or cold,

    Just thought i would post just in case it help anyone else out that has a simular issue.
    #17
  18. steveasap
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    steveasap New Member

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    I also had the same hot starting problem and found a loose fuel filter connection pipe which the jubilee clip looks like it had chewed up...
    Put a proper fuel line pipe clip on and cut back the hose...
    This is a great thread... Many thanks...
    #18

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