85 turbo - coughs on heavy accel load

Discussion in 'General Motoring' started by frenchy, Jan 19, 2005.

  1. frenchy

    frenchy Guest

    My 1985 lebaron Town and Country convertible runs fine around town, no
    idling problems, good get up and go. Only problem is if I happen to
    have to really push the motor, like trying to accelerate up a steep
    grade too quickly, or pass somebody and almost floor it, the motor will
    hesitate and lose power momentarily, as if the gas or ignition has
    almost been cut off, over and over again, till I lift off the gas a bit
    and accelerate slower. Sort of a "chug" where power drops out like
    it's going to die, then comes back quickly. What are the possible
    causes of this? If the knock sensor detected enough knock could it do
    this (I don't really hear knocking but I mostly ride with top down.)
    Maybe I should try a tank of premium first. Timing is set at Calif.
    factory setting. I think I changed the big fuel filter about 50K ago.
    Could it be dirty again and cause this? thanks!
    frenchy, Jan 19, 2005
  2. frenchy

    frenchy Guest

    clarification, this is a 2.2 turbo, 121,000 miles...Frenchy
    frenchy, Jan 19, 2005
  3. Depending on the timing of this "chug" event relative to when you mash the
    accelerator, it could be that the computer is detecting an overboost
    condition and is momentarily killing power to the ASD relay to bring the
    situation under control, or it could be something less exotic. Your first
    step is to check for flash codes.

    To check the computer codes:

    With the engine off, switch the ignition key on-off-on-off-on,
    leaving it "ON". Do not
    go to "start", just "on" during this procedure.

    Watch the "Check Engine" or "Power Loss" light. It will turn on, then go
    off, then will begin to flash-out any trouble codes that have been stored.
    For instance, if it flashes:

    flash <pause> flash flash
    <long pause>
    flash flash flash <pause> flash flash flash flash flash
    <long pause>
    flash flash flash flash flash <pause> flash flash flash flash flash

    Then you have a 12 (one flash followed by two) a 35 (three and five) and a
    55 (five and five). 55 means "end of codes" or, if by itself, "No codes
    stored. Check the codes and report what you find.
    Maybe you should diagnose the problem systematically and fix what's
    Yes, you are overdue for a fuel filter by about 20,000 miles if you're
    lazy, or 30,000 miles if you're smart.

    What else is overdue on your car...?

    Daniel J. Stern, Jan 19, 2005
  4. frenchy

    Steve Guest

    "Turbo" is key word. Sounds like over-boost shut down to me. Is the
    wastegate failing to open? Trouble codes set?
    Steve, Jan 19, 2005
  5. frenchy

    maxpower Guest

    Does the power loss lite turn on when this happens and then goes back out?
    If so it is going into overboost, check vaccum hoses to and from the turbo
    especially behind the valve cover and the hose at the bottom of the turbo,
    But it could be a number of things though, tune up? plugs/wires breaking
    down? Check for any fault codes in the power module............ Knock sensor
    would not cuase this.
    Glenn Beasley
    Chrysler Tech
    maxpower, Jan 19, 2005
  6. frenchy

    frenchy Guest

    Ok folks I dumbly forgot to check for any problem codes first, I'll
    check tonight. Did not notice the light coming on when problem occurs
    but this is with the top down in the sun going 60 so wasn't exactly
    looking for it, will observe it next time it happens. Will report back
    what I find. thanks...Frenchy
    frenchy, Jan 19, 2005
  7. frenchy

    frenchy Guest

    Oops the car is right outside, duh. Ok even though I just cleaned the
    battery terminals since the last time I noticed the problem (the time
    before last that I drove it), I just checked and sure enough I have a
    12 code (battery recent disconnect) and a 45 code (overboost) and 55
    (end test). If I pull on the overboost rod HARD with both hands, it
    moves away from the diaphragm and returns back ok. Free but hard to
    move, normal I suppose. How far should the rod be able to be pulled?
    Seems like about an inch. So what pushes the rod out of the diaphragm,
    the exhaust pressure? And the small hose is a vacuum hose to modulate
    it? Or are both hoses vacuum and they move the wastegate with just the
    negative vacuum (boost)?
    Have to wait till I get home to check the condition of the hoses.
    thanks again...Frenchy
    frenchy, Jan 20, 2005
  8. frenchy

    maxpower Guest

    dont worry about how far the rod moves,,check the vacuum lines, at the waste
    gate solonoid to the acuator, if your lucky you will just find it has a
    broken hose,
    maxpower, Jan 20, 2005
  9. 12 = "Start of Codes" when read via the dashboard light.
    45 = what I expected you'd find.
    Yep, there should be stiff spring tension on it, alright. But, you may
    want to remove the wastegate actuator rod from the wastegate lever and
    make sure the lever swings freely. If it is binding, it will cause
    overboost. Hitting the wastegate shaft with Mopar P/N 4318039AB
    penetrating fluid (do not substitute) usually eliminates the binding
    That's about right.
    No, intake manifold pressure (under boost).
    Your idea here is more or less correct, but there's no such thing as
    "negative vacuum". Boost is considered positive pressure and is measured
    in pounds per square inch (PSI). Vacuum is considered negative pressure
    and is measured in inches of Mercury (in. Hg). Both are considered
    relative to atmospheric.

    If there is a leak anywhere in the hose running to the wastegate actuator,
    overboost will result. Same if there's a faulty or sticking wastegate
    actuator vacuum control solenoid.

    And my question from before stands: You're long overdue for a new fuel
    filter, so what else has been let slide?
    Daniel J. Stern, Jan 20, 2005
  10. frenchy

    frenchy Guest

    Heyyyy, I just put on 4 new tires this week, noticed a busted CV boot
    and had them fix that at same time and changed oil and filter, I always
    keep oil and transmission fluid topped off, I slapped on a new timing
    belt recently, new distrib rotor, and I keep the fake wood varnished.
    I did notice I had let the power steering go almost dry so after
    refilling it I had them flush it out and refilled it again. I was
    thinking of getting a new Sebring but I can't let go of this darn
    frenchy, Jan 20, 2005
  11. frenchy

    Joe Pfeiffer Guest

    I've never heard of penetrating fluid before -- what's the
    distinction between penetrating fluid and penetrating oil?
    Joe Pfeiffer, Jan 20, 2005
  12. frenchy

    aarcuda69062 Guest

    Pure slapstick!
    aarcuda69062, Jan 20, 2005
  13. OK, that's good, but you've also got 50,000 miles on the fuel filter...!
    No insult is intended, just factfinding. How long since the entire
    crankcase ventillation system was serviced (much more than just replacing
    the PCV valve)? Spark plugs, plug wires, distributor cap? Air filter? How
    long since the throttle body was cleaned?
    Daniel J. Stern, Jan 20, 2005
  14. It's the new name for what Mopar used to call "Manifold Heat Control Valve
    Dunno, good question. 4318039AB (and its predecessor 4318039) smells quite
    unlike any penetrating oil I've ever used, and the smell is definitely not
    one of petroleum distillates. It also has a strange consistency. But
    nothing else works even close to as well on heat riser valves and

    Daniel J. Stern, Jan 20, 2005
  15. frenchy

    frenchy Guest

    Bingo, it was the bottom vacuum hose on the wastegate, it's rotting
    into friggin' cracked, melted rubber goo and had a big gash in it where
    it connects to the nipple. Was out of sight, and out of mind : \
    Guess this explains the damn wandering idle speed I tried to diagnose
    but could never figure out too. Yes it's got newer plugs, wires, dist
    cap, air filter, and I cleaned the throttle body like a clock back when
    I was trying to fix the goofy idle but gave up and lived with it. It
    would only do it sometimes, would quit doing it for a while, then start
    up again, and depended on whether car was warmed up sometimes.
    Apparently was just that rotten hose crack heating up and letting in a
    bit more vacuum some times than others. Off to buy some new hose
    tommorrow and will try to do better job of checking all the vacuum
    hoses this time too (I've found and fixed a few cracked plastic tube
    hoses in there before). Replaced the dist rotor once when the little
    plastic alignment pin broke and rotor just spun freely, that was a
    bitch to figure out!
    And I'll get another fuel filter. What do I need to do to clean the
    PVC system other than cleaning the valve? THANKS EVERYBODY!..Frenchy
    frenchy, Jan 20, 2005
  16. There y'go. Easy fix.
    *REPLACE* the valve if it's been on there a few years. Inspect *all* the
    hoses and rubber elbows in the system. Don't forget the one at the left
    rear corner of the camshaft cover, at the other end of which is a
    crankcase inlet air filter that needs periodic replacement.
    Daniel J. Stern, Jan 20, 2005
  17. frenchy

    maxpower Guest

    I figured that is what you would find, good for you!!!
    maxpower, Jan 20, 2005
  18. frenchy

    maxpower Guest

    Hey dicks back, hi Dick
    maxpower, Jan 20, 2005
  19. frenchy

    damnnickname Guest

    were rn12yc, some plugs will mess with the timing of the power module and
    cause all kinds of idle problems. Almost like it is searching because the
    timing is flucuating so bad
    damnnickname, Jan 20, 2005
  20. frenchy

    damnnickname Guest

    were rn12yc, some plugs will mess with the timing of the power module and
    cause all kinds of idle problems. Almost like it is searching because the
    timing is flucuating so bad
    damnnickname, Jan 20, 2005
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