Big problems with 89 Voyager - please help

Discussion in 'Voyager' started by Markus Klama, Sep 10, 2003.

  1. Markus Klama

    Markus Klama Guest

    Hello everybody,

    I have a 89 Voyager, 130k miles, with the 3.0L V6 engine and 3-speed
    automatic transmission.
    Recently the car became hard to start. Two days later the engine died
    when idling at a redlight. Back home (engine still runs, but not good) I
    checked the codes and the SBEC gave me a 54.
    So I started checking the photoelectric pickup assembly. I checked at
    the distributor-to-harness connector. Power is good (8.9 Volts), ground
    is good (3 Ohms from the connector to the battery ground) and the signal
    line delivers a beautiful digital clock signal (measured using an
    oscilloscope) while the engine is running. I cleared the codes, but
    after operating the engine, the "54" is back.
    During my examinations, I also noticed that every 10 seconds or so, the
    a/c compressor is engaged for about 1 second - although a/c is set to
    OFF at the control panel! The SBEC did not do this all the time ...
    after 2 minutes of 1-second-runs, it stopped ... and came back some 10
    minutes later.
    I disconnected the a/c clutch from the harness, thus forcing the
    compressor to stay off. Now it is even more noticeable that there's
    something going wrong. Whenever the SBEC tries to engage the compressor
    (it can't do this due to the disconnected clutch), I can hear a clicking
    sound (some sort of solenoid or relay) coming from the front left corner
    of the engine compartment. Also engine idle speed is raised to about
    1300 rpm during that 1-second-run.
    What the hell is going on? Any suggestions will be very much appreciated.

    Markus Klama, Sep 10, 2003
  2. Code 54 is "No fuel synch pickup signal". That'll certainly cause hard
    starting and stalling. Even though you may have a perfectly good signal
    out of both the low-rate and high-rate pickups in the distributor (you
    tested both, right?), the computer may not be seeing them properly,
    sometimes due to a faulty wire or corrosion at the 60-pin connector at the
    engine computer.
    Are you sure it's actually set to "off"? If you've got the Defog button
    pushed, it'll run the A/C compressor regardless of the compressor
    pushbutton position, and if your A/C system is low on refrigerant, it'll
    short-cycle. That is one mechanism by which such a symptom could be
    observed. Another is -- again -- corrosion or faulty connections at the
    engine computer. Another is an internal computer fault.
    The SBEC did not do this any of the time. An '89 has a SMEC, not an SBEC!
    You're hearing the A/C clutch relay, which is usually drowned out by the
    louder click of the A/C clutch itself. The idle speed increase is normal
    when the A/C clutch is engaged, to compensate for the compressor's load on
    the engine. All you have to do is figure out why the computer thinks
    you're requesting A/C.

    Daniel J Stern, Sep 10, 2003
  3. Markus Klama

    Markus Klama Guest

    Ok, of course I ckecked both of them and both clocks are there. I also
    measured the voltage at the clock lines at the distributor harness
    connector with ignition turned on: both read at 4.8 volts, thus telling
    me that that I've just seen the voltage which arises on an open digital
    input with internal pullup resistors. So the 60-way SMEC connector must
    be good.
    Note besides: if I disconnect the distributor from the harness while the
    engine is running, it dies immediately.
    I'm absolutely sure that it's set to "OFF". If I set it to "NORMAL", a/c
    runs smooth without any short-cycling. My a/c system is in perfect
    condition, as it is serviced twice a year by an a/c professional.
    You're right, sorry for the typing error!
    So how can I figure out who the hell is the cause for that intermittent
    a/c cycling while the system is turned off? I already disconnected the
    vacuum hose which runs from the power brake booster to the a/c control
    panel (I remember that my Chevy van did funny things with the a/c some
    time ago and it was just a defective vacuum fitting at the control
    panel). But that did not change anything.
    The a/c clutch is operated directly from the SMEC (unfortunately I don't
    have schematics for the SMEC, only for the SBEC, which has a different
    pinning layout). Can you tell something about the the signals going into
    the SMEC which are responsible for operating the a/c?

    Thanks a lot for your help,

    Markus Klama, Sep 14, 2003
  4. Markus Klama

    Markus Klama Guest

    Ok, so I started cleaning the throttle body, which is something that's
    never wrong. I also cleaned the AIS motor. I saw that the pintle was not
    in its retracted position (<= 1 in), so I twisted back the pintle.
    I also checked the distributor harness. I was able to see the 2 clock
    signals which run from the distributor to the SMEC. I could also verify
    ground and power (+5V) at the distributor harness... The distributor
    signals seem to be ok, when I pull the connector from the distributor
    harness while the engine is running, it instantly dies, as this engine
    does not have a camshaft or crankshaft sensor (I believe).

    After having the throttle body cleaned and the AIS motor pintle
    retracted, the car is easy to start now. Looks like that was the
    stalling problem. Although I cleared the codes, I keep getting that
    f***cking 54! And the "Check Engine" does not light up!

    I also still have the problem that the computer kicks in the a/c
    compressor now and then, although it's turned off. After looking at the
    schematics, I found out that the a/c control panel simply grounds a wire
    when the user selects a mode which requires compressor support. This
    wire then runs thru the high and low cutout pressure switches and the
    ambient temperature sensor switch and then it ends up at the 60 way SMEC
    connector. Now if ANY of those switches would open the line, the
    compressor should not engage anymore. So I simply pulled the connector
    from the high pressure switch. No change, the SMEC continues to run the
    compressor now and then (but always just for a second or two).
    Currently I'm driving with the a/c set to "Defrost", just to override
    that intermittent compressor engaging. This car has no cycling a/c and I
    dont' want to ruin the compressor. When I do this, there is no on/off
    problem. The compressor runs all the time (of course I had to reconnect
    the high pressure cutout switch).

    But what the hell can I do to track down the problem? Given the case
    that the SMEC is faulty, can this be diagnosed by hooking the car to the
    dealer's diagnose system?

    Could it be a vacuum problem? Or something around MAP or EGR? How can I
    do some "it cannot be this sensor" troubleshooting?

    Any suggestions will be greatly appreciated,

    Markus Klama, Sep 29, 2003
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