1994 Sundance stalls/runs rough when cold

Discussion in 'General Motoring' started by Sinerviz, Jan 22, 2006.

  1. Sinerviz

    Sinerviz Guest


    I have a 1994 Plymouth Sundance that is giving me a lot of headaches
    when the weather is really cold (below freezing)... It runs rough to
    begin with and when accelerating out of an intersection it often
    stalls, leaving me dead in the intersection or in the middle of the
    road (kind of inconvenient at times)

    I have replaced Spark Plug Wires, Plugs, Rotor and Cap, PCV Valve and
    hoses coming out of the valve cover (one that goes to PCV Valve and one
    that goes to air cleaner) I also installed the pre-heater hose that
    goes to the air cleaner as the previous owner apparently removed it.
    Although the car runs a bit smoother once warmed up after all this
    work, it still stalls on me. I really have no idea what else to check
    and hope someone else has had this problem and knows what will fix it.
    I have tried getting engine codes by turning the key on and off three
    times but it comes back saying no codes stored.

    If anyone can help me out, I would greatly appreciate it!

    Thank you,
    Sinerviz, Jan 22, 2006
  2. Check your heater hose routing. There's supposed to be engine coolant
    routed through the base of the intake manifold to warm it up. Also since
    we know that the thermostatic air induction system was at least partially
    tampered with (stove hose removed), you will want to check the operation
    of the thermostatic air cleaner itself. With the engine and ambient
    temperature cold, the air cleaner's damper door should block off the cold
    air intake up top, and take all intake air from the stovepipe you
    replaced. Just remove the stovepipe from the bottom of the air cleaner,
    and remove the cold air intake pipe from the front of the air cleaner, and
    cover each snorkel on the air cleaner, one at a time, with your hand to
    determine which one produces suction. The system aims to keep intake air
    temp at approx 100¡F, so the engine has to be good and warm, and the
    ambient temperature not very cold, before the damper door moves to the
    "heat off" (cold air) position.

    Daniel J. Stern, Jan 22, 2006
  3. Sinerviz

    Sinerviz Guest

    As far as I can see, all heater hoses are in check and there are no
    problems in the cooling system (no blockages or air pockets etc) as I
    just flushed the system and refilled it, making sure no air got
    trapped. The damper door seems to be completely shut when I start the
    car. I have yet to see it open up, but I have no watched it more than 5
    mins after running. But it is taking in the air from the stove which is
    what it is supposed to be doing.

    The only other thing I am having a problem with, although I am not sure
    if it is related, is the temperature gauge. The gauge always reads
    cold. I replaced the temp. sensor and it still did that, so then I
    went and replaced the gauge itself and it still doesnt work. if the car
    is sitting there idling (and its usually rough) and I unplug the wire
    that goes to the temp. sensor, the car seems to start running a bit
    smoother and the fan starts up. If I plug it back in, the fan stops
    and the engine runs a bit rough again.. is this any help?
    Sinerviz, Jan 22, 2006
  4. Sinerviz

    maxpower Guest

    The fan will turn on when you disconnect the coolant temp sensor and the
    check engine lite will turn on. Your vehicle is loading up at idle, you need
    to check the base engine vacuum at idle. If the engine vacuum is low (below
    17) the map sensor will think that the engine is under a slight load and
    cause the injector to stay open longer thus a richer mixture. Start with the
    basic......Check engine timing (disconnect that coolant sensor to check
    basic timing) and then vacuum.
    There is also a TSB out for a cold start problem....18-08-94
    Cold idle roughness (condition worse if engine speed is increased in
    neutral) and poor driveability, after a cold start, in 0 to 30 degree
    Fahrenheit temperatures. Condition lasts until the engine coolant
    temperature reaches approximately 50 to 60 degrees Fahrenheit. Instead of
    replacing the PCM, the 94 model will take a reflash. erase the software and
    install the updated software. This would be considered an emission update
    and should be covered under the extended warranty.

    Glenn Beasley

    Chrysler Tech
    maxpower, Jan 22, 2006
  5. The device you unplug that starts the fan and changes the idle is the
    temperature *sensor*. It talks to the SBEC (engine control computer) about
    the temperature of the engine coolant, but it does not talk to the
    dashboard gauge. The dashboard gauge is driven by the temperature
    *sender*, which is a smaller device located not far from the sensor.
    Daniel J. Stern, Jan 22, 2006
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