'91 940 Turbo ... Loss of ALL power at cruising speed

Discussion in 'Volvo 940' started by sactolarry, Oct 24, 2004.

  1. sactolarry

    sactolarry Guest

    My dad lets me use a '91 Volvo 940 turbo that loses power, all power, while
    driving down the highway. The first time it happened all the red lights on
    the dash went on; no engine power; no power steering or brakes, etc. I
    coasted to a off ramp and managed to get to a service station at the
    bottom of the ramp. AAA towed it to the family Volvo mechanic. He could
    find nothing. It started right up and I drove off. Since then it has
    happened three more times. Each time it starts up again after I somehow
    get it off the highway. It is currently at a dealer's in a distant city.
    They can find nothing either! Help! This is a dangerous problem! I'm in
    my last year of college. If I could afford it I'd just give the car back
    to my Dad and buy one that works. What I need is some idea of what's
    going on. Help!
    sactolarry, Oct 24, 2004
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  2. sactolarry

    Robert Dietz Guest

    There are several devices that need to be checked/replaced:
    1. Pull all the codes from the diagnostic socket. See:
    for instructions.
    2. Fuel Injection Combined relay (Failed/failing solder joints).
    3. Engine speed sensor if indicated by 2-1-4 code from above results
    4. Radio suppression relay (identical to the auxilliary fan relay). Turn
    key on, ground the cooling fan switch on the radiator. If thw fan runs
    swap the two relays and recheck. If the fan doesn't run replace both
    5. Heat the ignition amplifier with a heat gun to see if the engine will
    stop running. If it does stop, cool it with a choke tester to see when
    it will restart.
    6. Check the wiring at the injector resistor pack.
    7. Heat test the coil.

    In better tha 90% of the cases you will find the fix in one of the above

    Robert Dietz, Oct 24, 2004
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  3. i would guess electrical...shorts, fuses, relays,...does it sputter at
    all? or, just a "shut off", as if someone "pulls the plug"...don't use
    dealers...use or find a good independent volvo mechanic...you will end
    up w/a better velue...have him/her use the car for a few days , until
    it acts up for them...just rent a car to replace it, or a lot of ind
    volvo shops will have a old 240 you can use for a few days...good
    luck!!! watch out for trucks following you w/this problem....
    ~^ beancounter ~^, Oct 24, 2004
  4. sactolarry

    grtdane63 Guest

    Start here for some diagnostic ideas.


    grtdane63, Oct 24, 2004
  5. sactolarry

    James Sweet Guest

    So the engine is just stalling? You might be able to pop it in neutral and
    start it up while you're coasting if this happens again. As for why it's
    happening, I would suspect the hall sensor in the distributor may be
    failing. '91 940T is a nice car, hope you can figure out the problem.
    James Sweet, Oct 24, 2004
  6. sactolarry

    Barry Hobden Guest

    I experienced the same problem with my '92 940T. Replacing the fuel pump
    relay solved the problem.
    Barry Hobden, Oct 24, 2004
  7. Had exactly this problem with a 93 945T. Turned out is was the "crankshaft
    position sensor" whatever that is. Got it fixed and has run fine since.
    Diagnosed by an independent Volvo shop (worked just on volvo's). Hope this
    Howard Nelson, Oct 25, 2004
  8. sactolarry

    volvoguy Guest

    I would start with a check of the charging system. Almost sounds like the
    alternator is crapping out when it gets hot.
    volvoguy, Oct 26, 2004
  9. sactolarry

    HankL Guest

    There is a possibility that it is one of two things - the fuel pump relay or
    crankshaft position indicator. Unfortunately, it starts back up and it is
    hard to diagnose an intermittent problem. I'm not sure , but I think the
    relay for
    the fuel pump in question is whit - on the left side, and above the fuses in
    of the ashtray.
    The crankshaft sensor is a round devise, it stick up out of the transmission
    housing and has a small black wire attached that plugs into the middle of a
    in the center engine compartment firewall just below your windshield. There
    are also
    two black relays on the drivers side - located under your head light next to
    the radiator
    that need to be swapped. They are both the same.
    My guess is that you have the white relay problem - if you are rich, get it
    at Volvo -
    if not, go to a bone yard and solve your problem for $10.00. If it happens
    be the crankshaft sensor, it should be $20.00 at the same bone yard. Good
    luck / Hank
    BTW --- been there / done that......
    HankL, Oct 26, 2004
  10. Have you checked the fuel pump relay yet? If not then remove it from the
    relay tray and either resolder the main connections inside the relay or
    replace it with a known good item.

    Cheers, Peter.
    Peter K L Milnes, Oct 29, 2004
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