87 760Turbo Starts But Dies

Discussion in 'Volvo 760' started by John Smith, Mar 12, 2006.

  1. John Smith

    John Smith Guest

    Hello group,

    We acquired a 1987 760 Turbo wagon last year. Just under 160,000 miles,
    seemingly reasonable shape but no promises made. Had been used for mostly
    short local trips last few years. A sticker indicates that the belts were
    replaced at about 150,000 miles, a year earlier.

    Early last year, the car failed to start for the previous owner at 156,800.
    Mechanic replaced fuel pump relay, fuel pressure regulator, cooling temp
    sensor and distributor ignition assembly ($276). In May, the car failed to
    start again, just after doing over 200 highway miles. Another mechanic
    found engine block soaked with gasoline and cleaned everything up again. He
    replaced the fuel pump ($213) to try to solve the flooding problem.

    The next day, the car passed state inspection for safety and emissions. A
    high point of our turbo brick ownership to date. A week later, it was dead
    in the driveway again and this time we towed to a Volvo dealer.

    The dealer mechanic also found fuel pouring out of the cylinders - stopped
    when injectors were unplugged. He checked compression and found all
    cylinders over 140 psi. They spent a lot of time checking ground wires and
    cables and repaired several shorts. But still no clue on the fuel problem.
    So we bit the bullet and replaced the Electronic Control Module ($993) and
    car left dealer running well.

    In the next six months we drove another 2,000 miles or so, mostly short
    trips, some highway. But with the onset of winter it started dying with
    growing frequency and now it's reached the point where I haven't made it out
    of the neighborhood in two weeks.

    When left to sit for a time, the car starts quite readily but will die
    within 35-45 seconds. If I do manage to get the car warmed up and try to
    drive, it lately tends to die suddenly while in motion. When the
    start-die-restart process is repeated too many times, the car refuses to
    start at all as if flooded -- yet I don't smell gas when I stick my head
    under the hood. Part of the problem is when the idles speed swings up and
    down "searching" it tends to die at the low end of the search. But that
    happens less often than the engine just quits with no provocation. And that
    seems to be happening with increasing regularity.

    The question is what to investigate to find the cause of this. I have
    acquired a shop manual and begun getting familiar with the basics. I would
    like to make this car run well enough to do at least a few more thousand
    miles of short trips -- it's getting to be a personal challenge!

    Therefore, I would greatly appreciate the value and benefit of any guidance,
    suggestions, lessons learned, etc. regarding where I should start looking
    for a solution to this problem. I have read a lot of good advice here so
    I'm hoping for a bit more to help me target my effort. Thanks very much.
     
    John Smith, Mar 12, 2006
    #1
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  2.  
    ChampaignTurbo, Mar 13, 2006
    #2
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  3. I'm somewhat new to the VOLVO game, but I have a 1990 Turbo wagon and
    one of the things everyone who knows anything said to me was to check
    the wiring harnesses. Apparently they were made with rather shabbily
    during the mid 80's and can lead to a wide range of problems for the
    car.
     
    ChampaignTurbo, Mar 13, 2006
    #3
  4. John Smith

    User Guest

    On a Volvo flooding can only occur a few ways. If the control unit is
    bad and won't pulse the injectors, if the diaphragm is ruptured in the
    fuel pressure regulator raw fuel pours directly into the intake
    manifold, or if the coolant temperature sensor is defective in such a
    way that it thinks the temperature is very cold but warmer than -84*F.
    The third option could be due to a faulty or defective engine harness.

    First, however, you need to find out whether the engine loses fuel
    first, or spark first, and then once it won't start whether it's missing
    fuel or missing spark or both. Then we can proceed.

    Bob
     
    User, Mar 14, 2006
    #4
  5. John Smith

    TEF Guest

    I have an '87 740 turbo (viturally the same car as the 760) and had the same
    problem with the car starting, but not running. The problem was the fuel
    pump relay. It is a plug-in module under the hood that cost less than
    $20.00. It takes only about 3 minutes to remove one and plug in a new one.

    As for the late '80's volvo being poorly made. I bought mine new in '87 and
    after 100K miles it continues to run fine without a single major problem.
    When it does break, it is far easier and cheaper to repair than my 2001 V70
    Turbo.
     
    TEF, Mar 14, 2006
    #5
  6. John Smith

    James Sweet Guest

    The cars aren't cheaply made, the engine wiring harnesses are made with
    poor insulation though. If yours hasn't died due to a rotting harness
    yet, it will.
     
    James Sweet, Mar 14, 2006
    #6
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