'85 240 woes...

Discussion in 'Volvo 240' started by Evi, May 2, 2008.

  1. Evi

    Evi Guest

    I'm having issues with my Volvo, and I can't quite figure them out.
    Maybe someone can help?

    When I'm accellerating (or when I'm not), it feels as if something's
    pulling back on the car, or like it's not getting fuel for just a
    second. Almost like if you were running, but someone had a string
    tied around your waist and jerked on it every so often, causing you to
    slow down but not stop completely.

    The impulse generator went bad, we replaced that. We changed out all
    of the spark plugs and wires (it was time for a tune up), and the
    battery connection is fine. I don't think it's electrical.

    We went through the fuel system; we checked the line, the fuel
    filters, the pumps, the fuel pump relay, and all the wiring - it's all
    good. I can't really figure out what it might be.

    Anyone got any ideas?
     
    Evi, May 2, 2008
    #1
  2. Evi

    Bill Bradley Guest

    As weird as it sounds, have you checked the gas cap? If the vent
    fails, the evaporative control system will pull a vacuum on the tank
    which the pump has to work against. Easy check: when the car is
    behaving this way, shut it off and open the gas cap. If you hear a
    sudden in-rush of air, that's your problem.
    I wouldn't rule out electrical though. Be sure to check ALL the ground
    wires to the block, especially the braided wire from the last bolt on
    the valve cover to the firewall, since a loose ground can cause a
    voltage error across sensors or even cause the injectors not to open.
    Also check the wiring harness at the firewall...sadly '85 is one of the
    years with the infamous GM-sourced wiring harnesses that have a nasty
    habit of crumbling when they get older.

    Bill
     
    Bill Bradley, May 2, 2008
    #2
  3. Evi

    James Sweet Guest


    It's almost always the wiring harness that causes this, usually the coolant
    temp sensor or air mass meter wiring shorts to something else and the ECU
    thinks the engine is either colder or hotter than it is, making the mixture
    much richer or leaner than it should be but it's worth replacing the vacuum
    lines too.
     
    James Sweet, May 2, 2008
    #3
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