960 '94 - idle problem

Discussion in 'Volvo 960' started by nimeya, Jul 5, 2007.

  1. nimeya

    nimeya Guest

    I have a '94 960 with idling problem (no idle, very high idle 2000 rpm).
    The car runs on LGP and petrol and I have the issue in both mode
    I have changed the idle control valve and the air mass meter (second
    hand parts) without result

    For now I have replaced the control valve with a manual one and it is
    working "fine" in LGP mode, but it is still unusable in petrol mode (the
    engine speed is fluctuating, and stops, even when I accelerate).

    It seems that the idle control valve is receiving some bad signals but I
    don't know which sensors are involved (temperature, AC, pollution, ...).

    Any help is welcome.
    Thanks in advance,
    nimeya, Jul 5, 2007
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  2. Hi we are in the same boat with our idle on a 1988 turbo volvo even the
    Volvo guys are stumped .I cleaned the throttle body idle control and still
    it will go for a while then play up .Its a safety issue too as it goes up
    down when it feels like it with no warning .
    John Robertson, Jul 6, 2007
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  3. nimeya

    Peter Adler Guest

    And the same here with my '90 765T, B230FI. It's resting at the moment
    because I'm tired of chasing down every last little thing that could be
    wrong with it and still not finding a solution. The idle problem got
    steadily worse and the car is now undriveable. It's also running extremely
    rich. Here's what I've done so far:
    New air filter/fuel filter. Cleaned out IAC. Checked and adjusted
    throttle & switch. Cleaned inlet galleries etc. Checked AMM. Checked all
    vacuum lines etc. for leaks. Replaced inlet manifold gasket. Pulled all
    possible relays, cleaned points, checked continuity of coils, checked
    circuit boards. Replaced coolant temp sensor under inlet runner 3. Replaced
    O2 sensor. Pulled all related connectors, cleaned with contact cleaner,
    reassembled with silicone grease (except O2 sensor leads -- they're best
    left bare). Replaced spark plugs and leads. Cleaned injectors, tested for
    leaks and spray pattern, reassembled with new seals. Cleaned and reassembled
    all ground contacts. Bench tested fuel pressure control unit and checked
    fuel line pressures. Replaced rusty section of fuel return line and checked
    for unrestricted return flow. Checked rpm sensor for continuity (couldn't
    get the thing out but it looks okay). Tore out hair. Said rude words.
    And I've probably done other stuff that I don't remember now.

    Is there anything I've overlooked? Is there anything you guys have done
    that's made the slightest difference?

    I'd be really, really interested ...

    Pete (fP)
    Peter Adler, Jul 9, 2007
  4. How have you checked the AMM? The connector on mine has become intermittent
    in recent years; I pull the connector off and clean it with isopropyl
    alcohol then reconnect it for another several months' use. When bad the idle
    becomes low and lumpy and the engine power is terrible. During the lumpy
    idle I can lift up on the AMM connector and it will surge then smooth out.

    Michael Pardee, Jul 10, 2007
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