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Thread: throttle butterfly opening ..

  1. #1
    Join Date
    Nov 2006
    Bogota Colombia

    Exclamation throttle butterfly opening ..

    Hi I have a small problem that I would prefer to solve with the right information:
    Range rover p38 4.6 HSE 1998 I took apart the plenum chamber to clean the system , I cleaned every thing but did not think the problem that I was getting into :::I cannot find anywhere the Throttle butterfly opening spec .I took out the small Allen screw that is the stop point for the accelerator system and did not check the opening of the butterfly inside now I have a great daub, haw much open should I live open the butterfly ?I have it at this point at o.5 mm difference between the upper one and lower one from the outside 74 mm/up and 74.5mm dawn but then the automatic gear box is not in right range from the throttle potentiometer .Do you have any info on that ?
    Saludos cordiales,


  2. #2
    Join Date
    Jan 2007
    Cardiff, UK


    Hi, Pascal.

    I'm not completely sure about the 4.6, but based on other versions of the RV8, the throttle butterfly should be adjusted to fully close at rest without going overcentre (i.e. perfectly vertical, no difference between top and bottom measurements). The ECU will control the idle speed to 700rpm automatically using the idle air bypass valve.

    Once you've set the stop, you'll need to adjust the throttle cable using the thumbwheel on the cable sheath. Adjust it so that all the slack is taken up (i.e. the throttle is just about to lift off the stop) then back it off by a quarter turn only - if you don't adjust this right the auto transmission won't work properly.

    Finally, check the cruise control cable adjustment - push the lever towards the plenum using light finger pressure to tension the cable. Check that there is between 0.5 and 1.5mm clearance between the cruise control lever and the throttle lever. If it needs adjusting, use the thumbwheel on the crusie control cable outer sheath to achieve the right clearance.

    Hopefully this should sort you out - if not, then I'm afraid you'll need to have the system hooked up to a Testbook or equivalent to set it up based on the throttle position sensor.

    Hope this helps - let us know how you get on.

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