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380SL throttle switch

Discussion in 'Electrics, Vacuum, Ignition and ECU' started by Traymore, Dec 28, 2012.

  1. Traymore

    Traymore New Member

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    Joined:
    Dec 27, 2012
    Your Mercedes:
    1984 380SL
    Hi all

    I have been scouring every forum i can find to try and solve the issue with my 1984 380 SL.
    The problem i am having is that once she has warmed up if the throttle pedal is pressed and released 9 times out of 10 she stalls, this also happens if the pedal is released whilst driving, to apply the brake for instance.
    She is now off the road as it is quite scary to loose braking assistance and power steering whilst driving.
    I have checked vacuum hoses, fuel pumps etc and whilst going through these checks i have found an electrical connector which is not plugged into anything.
    I have traced the wire as best i can and it disappears under the inlet manifold at the front of the engine, my best guess is that it goes to the throttle position switch.
    It makes sense in my head that this could cause the issues i am experiencing.
    Can anybody help with information as to the location of the socket for this plug, i have searched for ages and found nothing.

    Thanks in advance for any help.
     
  2. television

    television Always remembered RIP

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    Joined:
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    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    I am not 100% on this but is not there only 1 throttle switch that switch from the idle to the main computer, if this plug was out it would be running on the fail safe high idle of about 1k rpm
     
  3. OP
    Traymore

    Traymore New Member

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    Joined:
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    Your Mercedes:
    1984 380SL
    Hi television

    I am not 100% on this being the throttle switch as every diagram i have found shows a 3 pin connector and this only has 2, but as all i can find are US diagrams and i am 99.9% sure the wire is attached to the sensor/switch on the side of the throttle body i am guessing the UK wiring is different.
    I have just discovered the engine may have been replaced with one from a SE as the engine number is 116 963 12062800 could this explain it?
     
  4. television

    television Always remembered RIP

    Messages:
    164,074
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    Joined:
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    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    Let me do some checking on that engine number :D
     
  5. television

    television Always remembered RIP

    Messages:
    164,074
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    310
    Joined:
    Mar 14, 2005
    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
  6. OP
    Traymore

    Traymore New Member

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    Your Mercedes:
    1984 380SL
    thank you very much

    i will have a search through and see if anything looks familiar
     
  7. television

    television Always remembered RIP

    Messages:
    164,074
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    Joined:
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    Location:
    Daventry
    Your Mercedes:
    2002 SL500, 216 CL500, all fully loaded
    I do have all the details of the injection systems for these cars, I will look through and see what had 2 pin connectors
     
  8. OP
    Traymore

    Traymore New Member

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    Joined:
    Dec 27, 2012
    Your Mercedes:
    1984 380SL
    Hi television

    Thanks for the help i'm quitin for the night.
    I am going to try and trace the wiring from the idle control relay and see if i can work it back to the throttle switch connector in the morning, I will let you know how i get on.
     
  9. OP
    Traymore

    Traymore New Member

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    Joined:
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    Your Mercedes:
    1984 380SL
    OK this just seems to get more confusing for me.
    I have done some investigating today and found that none of the idle control wiring colours from any diagrams i can find match the pin outs on my idle unit.
    I am now 100% sure the plug i have found disconnected is going to the throttle switch/sensor on the side of the throttle plate body.
    I have also measured the resistances
    Idle position =6.95Mohm
    OT and WOT =>Meter can measure
    seems this switch/sensor may be faulty but no point replacing it until i can work out where it plugs in.

    image (7).jpg

    image (6).jpg

    I have attached some pics of the idle relay connector to identify each pins connected wire colour in the hope someone will know where i can find diagrams to match,

    image (3).jpg

    image (4).jpg

    image (5).jpg

    any help would be much appreciated
     
    Last edited: Dec 29, 2012

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