Adjusting idle speed and ignition timing.

Forum Modellspecifika forum OG900 Adjusting idle speed and ignition timing.

  • Detta ämne har 10 svar, 4 deltagare, och uppdaterades senast 2019-01-02 13:48 av .
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  • #453047

    I bought a 900 1988 2 liter kat in the north of Sweden with 180000km I drove it 5000km to my home in Spain.

    I got the car in a barn and I had to replace the distributor on site, I didnt have the time to make a proper adjustment of the idle speed and the ignition timing on site. I could drive the car 5000km without not issue and also I got the car to the anual inspection in Sweden and they didnt say anything about result of gas analysis, so I asume that the ignition system shouldnt be so bad.

    The thing is that now in Spain I want to change the sparks, adjust the idle speed and the ignition timing.

    I got some questions

    1REgarding the adjusting the IDLE speed my car has an idle speed off about 1200rpm so I asume that I have to adjust the screw located in the throttle housing. Is that correct? can anyone point in a pic where is the throttle housing?

    2 Regarding the ignition timing I understand that I have to point with an strobolight to the flywheel and check that the rotation marks are aligned. But, can anyone point where is the flywheel in my car.

    And the last question is what should i do first, adjust the idle speed or the ignition timing?


    Janne Hagnell

    If you have a functiobal idle, start with timing. Long time since I done this on a 900 but isn’t there a opening in the cover where you are supposed to point the strobo? The flywheel is in the front since the engine is mounted backwards.

    96 V4 1975 ”Bollen”
    96 V4 1979 ”Sköldpaddan”


    Is it a 8V or 16V Engine ?
    Can you post a picture of the Engine?

    When adjusting the ignition, it´s important to have correct revs on the engine.
    There is a sign beside the fuse/relay box with instructions for timing adjustment.


    IT is a 8v 1988 Bosch CI (K-jetronic)
    I know how to check the timing ignition, but the problem is how to set before the idle speed. I post a picture of the engine.



    There is an adjustment screw on the top left side of the trottle housing.
    Look for a M6 screw, 10mm head, with a locking nut.


    Thank you
    I have located the screw, but my concern is if my car has automatic speed idle adjustment, some models have it. My car is a B201 H model of 88 with catalizator and Bosch CI (Kjetronic)
    Does this car has this sistem. I am following the Haynes book and says that I have to adjust the idle speed in cars with Bosch CI except models with catalytic converter and modulating valve. Do I have to asume that mine has catalytic converter but not modulating valve.?


    Dear Jose,

    With a catalyst you have the so called KE-jetronic system which is the mechanical injection system but with a special valve to fine tune the air/fuel mixture by aid of the signal from the lambdasond. The RPM at idling is controlled by what in swedish is called ”tllsatsluftslid” which is a valve by-passing the throttle to increase the idling rpm with cold engine. This can typically jam slightly and might need to be exercised and lubricated. Your high rpm might depend on a continuously open valve. Remove it and try to operate it by hand while lubricating it with 5-56 or similar rust losening lubricant.
    The air/fuel mixture shall not be adjusted, it is controlled by the lambdasond.

    Good luck!/Gunnar


    Thank you for your extense and very clarifying response. Could you point on this scheme where is located the valve.


    Hi I don’t see it in the figure, If I remember correctly it is attached to the thermostate housing, but I might be wrong. The easiest way to find it is to follow the hoses conencted on each side of the throttle. Try that, if you don’t find it, come back and I will try to find it in my SAAB Workshop handbook.
    Good luck!/Gunnar



    Hittade en bra bild!

    1. 190102.docx

    Tack så mycket

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