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2.5 AFB Glow Plug problem - advice needed

Grant_H Jan 11, 2014

  1. Grant_H

    Grant_H Member

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    Hi all,

    My engine seems very reluctant to start on these cold mornings, and I've done a little digging:

    Leaving the door open slightly so the interior lights come on, engage the ignition and the glow plug light comes on. Up until I hear the relay 'click' for the GPs, there is no change in the brightness of the interior lights, neither is there any movement on the dash battery gauge.

    Could this simply be a result of a blown fuse? Or are there any more likely places for a broken circuit?

    Many thanks.

    Grant
     
  2. Sulli79

    Sulli79 Active Member

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    Can you check the voltage then current at the glow plugs?
     
  3. aragorn

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    Have you ever changed them?

    If they're 12+ years old they could just be dead.
     
  4. Grant_H

    Grant_H Member

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    Hi, thanks for the replies. Yes, they were changed last year.

    I've checked the ECU box in the engine bay and both 60A fuses are fine. Any other areas?
     
  5. Grant_H

    Grant_H Member

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    BTW; where's the Glow Plug Relay on the 2.5 TDi and what's the number?
     
  6. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User quattro Audi A4 Audi Avant Owner Group TDi

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  7. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User quattro Audi A4 Audi Avant Owner Group TDi

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  8. Grant_H

    Grant_H Member

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    Thanks; I think I've found the relay it's the blue one number 202 (same as the fuel pump relay I believe).

    I was actually watching that youtube vid about an hour an hour ago :)

    I'm now down to finding a wiring fault; any multiplugs / connectors prone to breaking on these cars?
     
  9. Grant_H

    Grant_H Member

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    I think I'll buy a new relay though; just to be sure.

    Thing is though; it still clicks to engage. Can this still be defective if you can still heare the 'switch'?
     
  10. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User quattro Audi A4 Audi Avant Owner Group TDi

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    They can still be faulty if the contacts are burned. You can take the can off the relay to see whats going on inside. Best thing to check though is with a multimeter on the fuses. If you are seeing 12V there then the relay is good and the wiring up to there is good. disconnect the glow plug cap and check there next.
    you can check the glow plugs in situ, usually if they are less than 1 ohm they are good.

    Karl.
     
  11. Grant_H

    Grant_H Member

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    Thanks; the glow plug fuses being under the ECU cover in the engine bay, presumably?
     
  12. desertstorm

    desertstorm Moderator Staff Member Moderator VCDS Map User quattro Audi A4 Audi Avant Owner Group TDi

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