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rpm up & down while idling, fluctuate between 1.3k to 1.6k

Discussion in 'Proton' started by jedi, Aug 9, 2017.

  1. jedi

    jedi Senior Member
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    car : Proton wira 1.3 Manual, year 2000

    Without aircond, my rpm stays at 1500
    With aircond on, when compressor kicks in, it will drop to 1100. when compressor off, rpm fluctuate between 1300-1600rpm

    Especially at the traffic light, sounds like i am asking for a race with the car next to me...

    I installed FICD, at least my engine won't die when it's cold, but rpm problem remains.

    any clue ? thanks mates !
     
  2. vr2turbo

    vr2turbo Moderator
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    I think idling tuned too high. With FICD you should be able to tune it lower when without aircon, so when air con is on, FICD suppose to compensate back, unless FICD got problem.
    Normally if FICD not working, mechanic will tune idling higher without aircon on, so that when aircon is on and with the load, the idling will just be correct....
     
  3. sweelt

    sweelt Well-Known Member

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    can try adjust the base idle set screw, to compensate rpm up/down
     
  4. RENESIS VIII

    RENESIS VIII Senior Member
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    This one I think only applicable to MMC throttle body. VDO throttle body don't have this screw unlike our engines. Actually mine also got idling problem. Rpm is always higher than 1000 and when air cond compressor kick in, will drop to 800 and cause slight vibrations. If on a hot day, even worse because rpm will drop further to 500 and the rpm just jump up and down from 500 to 800 back and forth.
     
  5. vr2turbo

    vr2turbo Moderator
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    Tune a bit higher to 1200 or 1300 then when air con cut in will be 900 to 1000
     
  6. RENESIS VIII

    RENESIS VIII Senior Member
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    Tried already. If adjust the screw too high, then the RPM will stop at 1500 rpm and drop down again to 1000 then rise back up to 1500. Can't really adjust much. Asked a few mechanic before, all of them said throttle body problem.

    During hot afternoon when RPM drop to too low when air cond on, it really troublesome because power steering is also affected. Steering becomes very heavy and I had to step on the throttle to make it easier to turn the steering.
     
  7. vr2turbo

    vr2turbo Moderator
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    Don't tune to 1500. There is a maximum, once you reach that the engine will idling like race car, going up and down......lol
    Tune slightly higher from your say 1100, maybe to 1300 and try out....
     
  8. RENESIS VIII

    RENESIS VIII Senior Member
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    Now my idle is already at 1100 to 1400. Fluctuating between these range when air cond compressor haven't kick in. I tried set the idling to be higher and rpm will be at 1000-1100 when compressor kick in but after that, rpm will go up and down.
     
  9. Izso

    Izso Boooooossst
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    What model? MMC or VDO? What did you do to your car recently? Completely stock?
     
  10. sweelt

    sweelt Well-Known Member

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    hehehe....."race car"
    idling is very tricky, can go crazy. Once out of accepted range, will make it even worst if keep on adjust blindly.
    Get the stock setting right 1st, than find whats the culprit.
     
  11. vr2turbo

    vr2turbo Moderator
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    IACV problem dy...:smokin:
     
  12. sanekit

    sanekit Well-Known Member

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    hmmm.. mine seems to go back to 800-900 rpm idling even after i adjust the BISS screw to a few times to set it to 950-1100rpm idling no ac. LOL. my ISCV is ok tho coz when AC on the RPM will rise +200-ish
     
  13. vr2turbo

    vr2turbo Moderator
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    If your ISCV is running no need tune higher dy
     

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