8v high idle

Discussion in '8-valve' started by eddiedebo, Apr 23, 2019.

  1. eddiedebo New Member

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    Hi

    I've tried to follow rubjonny setup for digifant timing and idle however when i set the idle and plug the blue sensor in again the idle shoots back up to 11-1200rpm.

    I have tried the procedure multiple times and every time is the same.

    It's a brand new genuine blue sensor.

    Any ideas?

    Thanks

    Andy
     
    Last edited: Apr 23, 2019
  2. rubjonny

    rubjonny Administrator Admin

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    did you check the idle switch is working as per my guide, plus checked the ignition timing?
     
  3. eddiedebo New Member

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    I've set the ignition timing with a timing light at 2250rpm with the blue sensor unplugged. Plug the sensor in and it advances the timing as it should.

    I may have missed the bit about the idle switch...what do I need to do?

    I've just read it again and I had not bunged the vacuum line to the UFO. Could it be a vacuum leak?

    Thanks
     
  4. rubjonny

    rubjonny Administrator Admin

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    make sure the idle switch clicks as the throttle is closed, to check it electrically you use a multimeter on the 2 pin plug round the back it should read closed circuit with the throttle closed, go open circuit when opened, and closed circuit again when throttle is wide open. to make sure the wiring from the plug to the ecu is good if you hold the throttle just off idle and press the full throttle switch on the top the revs should drop back to idle rpm.

    with the breather pipe you will need to block the side which goes to the inlet otherwise you have a massive air leak. the connection from the breather valve itself needs to be left open though. This is only needed when adjusting the CO% though and the oil is heavily contaminated as the block gasses will affect the readings. If oil is clean and/or just setting the idle you can leave the breather pipework alone.

    Worth checking the inlet pipe work all over for air leaks, the breather bung is a good one plus a few more tips in my guide
     
  5. eddiedebo New Member

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    I still have an issue with high idle but now it's only when the engine is up to temperature.

    I'm not sure if that points to anything specific?
     
  6. rubjonny

    rubjonny Administrator Admin

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    when its hot does the idle drop if you press the switch on top of the throttle? could be idle switch isnt quite makign contact or the wiring to the throttle switches isnt great. sometimes its the base idle drifting out of spec due to loose idle screw, if so repalce the o'ring to stop it winding itself out. sometimes its the ISV but not as common as people think, but the 2E code 2.0 8v MK3 isv is the same so swaps right over
     
  7. eddiedebo New Member

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    So I checked the idle switch and it wasn't making contact when throttle was closed. Adjusted so it now clearly clicks when throttle is closed. I thought I was going to have this solved but the high idle still persists. The wiring to the idle switch looks ok, no wires are obviously broken.

    The idle screw doesn't appear to move as it's screwed right in to keep the idle down.

    I have two isv's I've tried and neither seems to make any difference.

    Not sue what else to try now other than a new isv.
     
  8. rubjonny

    rubjonny Administrator Admin

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    need to reset the base idle & co as per my digifant guide now, as it wont have been set properly before with the idle switch not working. make sure the throttle is closed to the stop now you have adjusted the switch a bit, and go over the engine again looking for air leaks. the breather seal to rocker a prime suspect
     
  9. eddiedebo New Member

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    Ah ok that makes sense will go through your guide again this weekend. Hopefully that'll do it!

    I've already replaced the breather seal. Hoses and joints look ok.
     

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