Idle problems with a 245

Discussion in 'Volvo 240' started by Grizly Adams, Jul 9, 2003.

  1. Grizly Adams

    Grizly Adams Guest

    Got a 1990 245. starts fine, but if I dont keeps the revs up, as soon as it
    drops below 1k it stops. Changed the fuel pump relay with a known working
    one (940 and 240 FPR's are the same!), made no effect. Throttle possition
    sensor clicks when I move the throttle, so machanicaly thats ok.
    Checked the codes, were 1-4-4 and 2-1-4. cleared them, restarted the engine
    (several times, including driving up and down the drive, keeping the revs
    up), then checked the codes again, and there clear, shows 1-1-1, but car
    stil wont idle.
    Does anyone have any ideas. How do you check TPS and AMM are ok???

    TIA
    2 Volvo's Grizly (one sick one)
    Giant mutant cockroaches will be using it as their lowrider after the atomic
    bomb gets us and all the american cars.
     
    Grizly Adams, Jul 9, 2003
    #1
  2. Grizly Adams

    Rob Adlers Guest

    AMM is simple to check.

    While the engine is running, disconnect it. If the engine idle changes,
    that's one sign. The other sign of a failed AMM is if you quickly do a
    mini-throttle while the AMM is disconnected, it usually comes close to, or
    will stall.

    Have you checked your flame trap, and throttle body for dirt? How about your
    air filter in the airbox?
    I'd be checking for low air flow first in these situations.

    Rob
    Kitchener, ON, Canada
     
    Rob Adlers, Jul 9, 2003
    #2
  3. Grizly Adams

    andrewunix Guest

    Wed, 9 Jul 2003 14:19:35 -0400, suggested:
    : AMM is simple to check.
    :
    : While the engine is running, disconnect it. If the engine idle changes,
    : that's one sign. The other sign of a failed AMM is if you quickly do a
    : mini-throttle while the AMM is disconnected, it usually comes close to, or
    : will stall.

    I don't think I understand. Wouldn't the behavior with the AMM
    disconnected be the same whether it had failed or not?
     
    andrewunix, Jul 9, 2003
    #3
  4. Grizly Adams

    Brick_0 Guest

    Make sure your base idle is correct. You can ground the CIS (constant idle
    system) so you can set the idle. There's a connector near the firewall
    connected to a blue/white wire. Ground the wire and the CIS system will be
    overridden so you can set the idle.

    Check your injector seals for vacuum leaks. When cold (and/or hot) spray
    carb spray on each injector; if the idle changes your seals are leaking. The
    seals can leak when the car is cold but seal up when the car gets hot. If
    the idle problem goes away when the car is warmed up I would suspect vacuum
    leaks from somewhere.

    Check the car for vacuum leaks. The vacuum at idle should be between 16 and
    22hg. If the vacuum is low (10-14) at idle the car will stall easily.

    Make sure the ignition timing is set correctly.

    Make sure the CO is set correctly. A too lean setting will cause stalling.
    As a test, disconnect your O2 Sensor and see if the idle problem goes away.
    If it does then your car is probably running too lean. Sometimes the O2
    system will pull the CO too low when connected.


    Brick_0


    Changed the fuel pump relay with a known working
     
    Brick_0, Jul 10, 2003
    #4
  5. Grizly Adams

    andrewunix Guest

    Thu, 10 Jul 2003 16:52:16 GMT, suggested:
    : if I read the messages in the thread correctly, the car was running OK, you
    : had the air filter changed, and shortly thereafter it began to have the
    : problem? If so, I'd first think that the connector to the AMM might have
    : been knocked askew during the filter change, and finally worked itself loose
    : enough to cause the bad running. With the engine off, try removing and
    : reconnecting the connector to the AMM several times, leave it connected, and
    : see how the engine runs. I do this periodically on mine, whenever it
    : develops a rough idle or lacks power on acceleration, and it seems to fix it
    : each time!

    That sounds like the contacts are oxidizing. You might try shooting a good
    contact cleaner on the pins for the connector next time you do this and
    see if it holds up longer.
     
    andrewunix, Jul 10, 2003
    #5
  6. Grizly Adams

    Guest Guest

    been there, done that, didn't help much, but didn't hurt either! Used
    PROGOLD, a contact treatment that I've been using on other
    electronic/computer connectors for years, generally very good.... Since I
    only have to "work the connector" a couple times a year, that's an
    easy/cheap fix.....
     
    Guest, Jul 11, 2003
    #6
  7. Grizly Adams

    Rob Adlers Guest

    AMM connections going bad? Seriously?
    My thought at that point is the wiring harness is going bad.

    I also had a problem with starting / rough idle in damp weather. The
    electronic advance component that enters the distributor at the front of the
    distributor had a broken mounting point, resulting in water getting thrown
    into the distributor by the fan.

    If idle was OK then all of a sudden not, the AMM connector not being seated
    is one thing, but I've also heard from other folks where cracks in the air
    intake tubing resulted in poor idle / engine performance.

    Too me it sounds like an air / vacuum leak occurred. OH WAIT! I had rough
    idle also start once when the rocker cover bolts became loose (long story on
    that one). I tightened them down and it smoothed out, but I don't suspect
    that's what's happening here.

    The flame trap is located dead center underneath the intake manifold in the
    middle of a Y splitter tube that enters the engine head/block. Hard to see
    from a-top, but you can feel it with your hands.

    Rob
     
    Rob Adlers, Jul 15, 2003
    #7
  8. Grizly Adams

    Rob Adlers Guest

    Actually, the base idle can get screwed up if the throttle linkage is worn
    or broken.
    I had a problem where the spring clip was pretty worn from maintenance
    disconnection and it had free play, which resulted in unstable idle.
    Normally the idle switch should trigger the ECU to set up the idle speed,
    but occasionally my 'idle' ran high.

    Throttle body dirt is another source of bad idling, but this case sounded
    rather sudden, which leads me back to vacuum/air or electrical connection.
     
    Rob Adlers, Jul 15, 2003
    #8
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