99 Chrysler 300M 3.5L - Cranks, will not start

Discussion in 'Chrysler 300' started by hightide610, May 27, 2009.

  1. hightide610

    hightide610 Guest

    Ok, I am at a loss. Son called me from a friends house and said car
    wouldn't start, was running fine when he shut it off, got ready to
    leave 2 hours later and nothing.

    Went over to check things out, motor turned over normally, almost
    started "kinda acted like it is just not getting enough fuel" but
    would not run. Threw the car on a trailer, brought it to the house.
    Checked fuel pressure at the rail (46-48psi and holds for over 5
    minutes) put OBDII scanner on the car, no codes. Checked spark, got
    spark on all 6 cylinders. Checked injector pulse, (this is where it
    gets strange) on cylinders 1 and 2 I get 1 pulse on intial crank then
    nothing. Was really liking the cam or crank postion sensor for this so
    I back probed the cam position sensor and got a fluctuating 5vdc,
    checked crankshaft position sensor, nothing, pulled it and replaced,
    now I got good crank PS signal, went back to injectors, 1 and 2 now
    get erratic pulse (and I say that by comparison... because what I
    would expect to see, I don't so I worked my way toward the back
    cylinders... 3 and 4 seem more like what I would expect, but something
    still just doesn't seem right, so checked 5 and 6 and got more of what
    I would expect to see and I say that with this caveat.. I almost watch
    the noid light in shock, because I would not expect to see it react
    the way it does (borderline to much for just cranking the motor
    over).

    The only thing I have left to check is compression, thinking that
    would indicate whether timing belt took a dive (I shudder at this
    thought, but the car has 189,000 miles on it and has been very
    reliable). However... I have spark and unless I am missing something
    there is no way I am getting spark if its broke AND coupled with the
    cam position sensor giving me the a flucuating 5v reading when I turn
    the motor over with a breaker bar. Also, for S&G, checked resistance
    on both sensor outputs to ground got no short on either.

    I am leaning more towards the ECM at this point, and I have seen them
    just take a dive, but not willing to go out on a limb and drop $250
    without SOMETHING definitive.

    Is it possible for a Chrysler shop to bench the ECM off the car?

    Is it possible for it to jump time and cause the injector pulse to act
    this way?

    I am at a loss...
     
    hightide610, May 27, 2009
    #1
  2. hightide610

    Bill Putney Guest

    They have 189k miles on it on the original timing belt!? Forgive me,
    but if it did break, they would deserve a few bent valves. Change
    interval is 100 or 105k - depending on year - and they do not like to go
    much beyond that.

    I believe you'd still get spark based on the crank position sensor even
    if the cam position sensor is not getting blipped (not 100% sure about
    that, but I think I'm right).

    You can partially remove timing cover to inspect for broken or slipped
    belt, but at that mileage, it would be a miracle if it isn't broken.

    Sounds like it was at low speed (which is often when they break) which
    would lessen the likelihood of bent valves if it is the belt.
     
    Bill Putney, May 27, 2009
    #2
  3. hightide610

    Joe Pfeiffer Guest

    This isn't clear from the FSM -- the ignition timing is based on the
    crank sensor, but which piston will be at TDC comes from the cam sensor.

    Though if the timing belt has failed I'd expect a code from the
    resulting cam-to-crank sensor misalignment (I don't see anything in the
    FSM that looks definitive to me about whether that'll detect the case
    that no cam sensor input is happening, though).
    That would be very lucky, to say the least -- my daughter's Neon, with a
    4, passed a compression test after breaking a timing belt, but burned a
    hell of a lot of oil ever after. I'm not sure it's even possible to
    break a timing belt on a 6 without bending valves.
     
    Joe Pfeiffer, May 27, 2009
    #3
  4. hightide610

    Bill Putney Guest

    You could be right. It seems that I've read posts on one of the LH car
    forums by people who know that it is possible, though I couldn't tell
    you what secondary backup source the computer could possibly use to sync
    the pistons to the ignition - and it is entirely possibly that I am
    mis-remembering. I guess, as you suggest, I could imagine it (as a
    temporary or limp mode) being able to sync up with no crank signal
    before I could imagine it syncing up with no cam signal. On the other
    hand - it doesn't run at all now.
    I do know for a fact that it is often reported on the LH forums that a
    bad cam or crank signal will not always throw a code. In this case
    since it was a sudden no-run event, the PCM may not be seeing enough
    information to set a code - though it would seem that enough info. is
    there for it to know something (which is no good if the firmware doesn't
    exploit the info.), but nevertheless it is known not to under a few
    failure scenarios (bad position sensors being one of them, though bad
    position sensors sometimes will set a code, and I think broken timing
    belt will not set codes - again, could be mistaken).
    The broken timing belt threads we see on the LH car forums very often
    report the event happening immediately at startup or at low speeds (not
    difficult to imagine that the more pulsatile/high-peak stresses on the
    timing belt would occur at the lower speeds when smoothing flywheel
    effects on the cam are for all intents and purposes absent.
    Strange. Do you have any idea why that would be? I'm having trouble
    thinking of the connection between the timing belt failure and burning
    oil. Not doubting - just trying to visualize. I guess it is possible
    that the two just happened to start occurring around the same time.
    Yes - it definitely is possible - we see broken timing belt threads in
    which the valves were *not* bent as well as ones in which they *were*
    bent. Obviously the chances of successfully "running between the
    raindrops" is statistically greater at low speed based purely on the far
    fewer number of after-break revolutions of the crank and cams from
    flywheels effects on both. I get the impression that the of crank
    rotation degrees of possible interference-to-360° ratio is rather small
    which would of course, combined with breakage at low-speed operation,
    decrease the chances of valve/piston disagreements during the event.
     
    Bill Putney, May 27, 2009
    #4
  5. hightide610

    Joe Pfeiffer Guest

    My guess was valve guides -- lots of blue right after startup.
    Good to know (though I sure hope I never have occasion to test it!).
     
    Joe Pfeiffer, May 27, 2009
    #5
  6. hightide610

    Bill Putney Guest

    But can you figure out a connection to the timing belt breaking? I can't.
     
    Bill Putney, May 28, 2009
    #6
  7. hightide610

    Joe Pfeiffer Guest

    My guess was shock from light contact between piston and valves. Enough
    to damage stems/guides, but not enough to fail a compression test, is a
    stretch I'll grant you...
     
    Joe Pfeiffer, May 28, 2009
    #7
  8. Hi!
    If GM could do it on the late 80s 3800 V6, I'd have to think that Chrysler
    could find a way to do it as well. (I have two Buick cars--an 88 and an
    89--that both have something wrong with the cam sensing. (It doesn't seem to
    be the sensor.) They will run and drive fine. But the ECM can't enter
    sequential fuel injection mode without a report from the cam sensor, so it
    sets a code.)

    But that's neither here nor there, I'm just throwing it out.

    William
     
    William R. Walsh, May 28, 2009
    #8
  9. My aunt's '92 Buick Regal Custom with the 3.8/3800 series I has the MIL on
    for the same reason. It came on when I floored it to merge back onto the
    interstate while coming back to Iowa from Oklahoma and has been on ever
    since. Strangely enough the car seems to run better now than it did before
    as before it would chug and sputter for the first ~30 seconds after being
    started and now it starts right up and idles smoothly.
     
    Daniel Who Wants to Know, May 28, 2009
    #9
  10. Hi!
    Interestingly, the '88 Buick turned its light off for quite some time after
    I woofed on (="floored it") it one day. I'm not sure why this would have
    caused the sensor or whatever excites it (probably magnetic) to start
    working. Then the engine light flickered every now and then for a few minuts
    and finally it came back on. It has stayed that way since.

    On a whim, I tried woofing on the gas in the '89 car while going down the
    highway, but it did nothing.

    I have no idea what is going on here, and it's off-topic for the group. I
    really don't care too much, and the cars don't seem any worse for the wear,
    so...

    William
     
    William R. Walsh, May 28, 2009
    #10
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.