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P38 cold start issues

Discussion in 'Range Rover' started by bionicbob, Jul 5, 2020.

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  1. wammers

    wammers STILL BREATHING. Donater

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    I have hot start on my P38 only one wire is cut and linked through hot start. There is obviously a power feed and ground to hot start. Can't think why two separate coded wires are joined together. The hot start tells the ECU the engine is cold so the ECU switches on glow plugs. Ok my bad, look for a wire that is Grey/blue that is the feed from ECU temp sensor to ECU. It is that one that is cut a connected to hot start. Not the one i said before. But you maybe best to disconnect hot start and repair the wires. It is screwing something up. You may even get a dash temp gauge back working.
     
    Last edited: Jul 6, 2020
  2. bionicbob

    bionicbob Member

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  3. bionicbob

    bionicbob Member

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    the red/white as been used to power it
     
  4. wammers

    wammers STILL BREATHING. Donater

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    There should be a power feed and ground that is a given. But it should also have the feed from the ECU temp sensor cut and joined into it that way is intercepts the sensor signal and tells the ECU the engine is cold the ECU then sets cold start fuel and switches the glow plugs on.
     
  5. wammers

    wammers STILL BREATHING. Donater

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    As said the hot start may not be switching the plugs on for long enough or the connections to the plugs maybe slack giving reduced power to them. You will have to check it. Sorry about wiring cock up i am trying to do several things at once.
     
  6. bionicbob

    bionicbob Member

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    yes they have used the blue/white wire
     
  7. Datatek

    Datatek Well-Known Member

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    Some hot start mods can disable the ECU temperature sensor when they go wrong and prevent correct operation of the glow plugs
     
  8. bionicbob

    bionicbob Member

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    it is starting fine with out it when warm
     
  9. Datatek

    Datatek Well-Known Member

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    That may mean the sensor is duff so the ECU is using the cold start settings which is the same thing the Hot Start mod does.
     
  10. bionicbob

    bionicbob Member

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    dosnt put the heater light on when warm even tho gauge isnt moving
     
  11. Datatek

    Datatek Well-Known Member

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    Forget the gauge, it has nothing to do with the engine ECU, glow plugs or anything else, it's a stand alone device.
     
  12. bionicbob

    bionicbob Member

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    when i warm it up and restart it no heater light now
     
  13. Datatek

    Datatek Well-Known Member

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    So the temperature sensor for the ECU may be working, you will know when you get your Nanocom.
     
  14. bionicbob

    bionicbob Member

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    will see how it starts in the morning when cold
     
  15. wammers

    wammers STILL BREATHING. Donater

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    Have you checked the glow plug connections to the glow plug relay?
     
  16. bionicbob

    bionicbob Member

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    Will try that tomorrow but like I said earlier may have found a fuel leak which is why it takes 3 or for atemps to start in a morning
     
    Grrrrrr likes this.
  17. wammers

    wammers STILL BREATHING. Donater

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    When the glows are active on cold start the fuel lift pump runs whilst the glows are lit. Fuel cant really run out of the injection pump to below the level of the pressure head inlet.
     
  18. bionicbob

    bionicbob Member

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    Notmaly in a morning give it one heat and it fires then just turns over the second and third heat just turns over untill I try a forth time then fine all day
     
    Last edited: Jul 6, 2020
  19. Grrrrrr

    Grrrrrr Technician, Bodgit & Scarper Ltd

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    My vote is fix the fuel leak and then test again. Beru glow plugs make a big difference. Expensive but worth it.
     
  20. wammers

    wammers STILL BREATHING. Donater

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    Still sounds like plugs.But have you checked the lift pump?
     
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