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misfires, rough cold idle V50

posted by  someone claiming to be Panhorst on  Sat Jun 18 11:06 CST 2016 [RELATED]

My 05 v50 T5 (128K, auto) has shown misfire codes of 300-305 a couple of times in the last few weeks and recently when I drove it (my wife's car) I noticed a rough cold idle. Also noticed that the check engine light came on when I started it once. Reading a few posts about similar problems indicates to me that the cause could be any number of things. Any tips on where to start?

I've added Techron, checked all the wire connections at the coils, and was considering replacing the plug wires (which are original) but FCP does not stock them and I can't tell where the lead starts anyway. It has volvo plugs installed about a year ago.

Thanks in advance.







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    misfires, rough cold idle V50

    posted by  KlausC on  Sun Jul 31 18:09 CST 2016
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    last visit: Fri Oct 24 10:15 CST 2014
    [RELATED]

    Low voltage before startup is a valid cause. Check for vacuum leaks. Has the PVC plumbing been checked? Is the coolant temperature sensor 'off', too low or high?

    How were the spark plugs when you pulled them?

    Check the fuel pressure at the end of the fuel rail, it should be around 42psi.

    Does the starter crank a lot when cold?
    --
    Keeping it running is better than buying new








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    misfires, rough cold idle V50

    posted by  KlausC on  Sat Jun 18 13:26 CST 2016
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    last visit: Fri Oct 24 10:15 CST 2014
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    Your car doesn't have plug wires. I suggest pulling all 5 spark plugs, cleaning them with a wire brush, check the gap (.028), note which plugs are very dirty, and get ready to buy new coils.
    --
    Keeping it running is better than buying new








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      misfires, rough cold idle V50

      posted by  someone claiming to be Panhorst on  Sat Jun 18 18:31 CST 2016 [RELATED]

      OK. Thanks Klaus. At least those are tasks I can do to save the labor costs. Should I replace all five coils at once? I get misfires on all five cylinders. Is this typical of V50s or Volvos in general?








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        misfires, rough cold idle V50

        posted by  KlausC on  Sat Jun 18 18:49 CST 2016
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        last visit: Fri Oct 24 10:15 CST 2014
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        I suppose the coils are OE, or 11 years old. Normally, I would say replace one at a time and see if there is improvement.

        Pull the plugs and inspect them first. I suspect some of them will be fouled worse than others. Check the coils for cracks, etc. on those fouled plugs.

        Count the number of 'bad' plugs and order that many coils. You may have to buy 5 and try to save a 'good' one for the work bench.

        --
        Keeping it running is better than buying new








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          misfires, rough cold idle V50

          posted by  someone claiming to be Panhorst on  Wed Jul 6 06:06 CST 2016 [RELATED]

          Klaus,
          I ordered five coils from FCP and installed them and the car runs smoothly but the same misfire codes have appeared.

          FCP may have sent the wrong coils because they are a half inch longer than the originals but I managed to get them on the car. When I ordered them I got a message that they would not fit so I called and a rep put me through to a supervisor who specified a different, more expensive, coil that they sent. I'm now in discussion with FCP about that.

          Assuming that the current coils are correct for my car, any other ideas about resolving the problem that is causing the codes?

          Michael







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            misfires, rough cold idle V50

            posted by  Herb Goltz on  Wed Jul 6 08:03 CST 2016
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            last visit: Fri Oct 24 13:23 CST 2014
            [RELATED]

            I think it would be unusual for all coils to fail at once (you are seeing codes for all 5 cylinders, correct?). I would look for another cause of these symptoms-- can you measure the voltage across the battery terminals with the car running with the headlights on? I am curious whether you have low alternator output, or something in the electrical path that would result in the coil packs not firing correctly.

            Good luck!








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              misfires, rough cold idle V50

              posted by  someone claiming to be Panhorst on  Sun Jul 31 11:00 CST 2016 [RELATED]

              The latest development in this saga is that the local shop looked it over and couldn't find anything wrong. They suggested taking it to the $dealer$ or another local shop that specializes in European imports. They also mentioned that it may be the Engine Control Module $$$.

              Any other ideas?

              The car runs fine except for a rough idle for a few seconds when started from a stone cold stop. It's got the correct, brand new coils (5) on it. The misfire codes show up just a few starts after clearing them.

              Many thanks,
              Michael








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                misfires, rough cold idle V50

                posted by  hf63 on  Mon Aug 1 07:25 CST 2016
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                last visit: Wed Oct 22 15:19 CST 2014
                [RELATED]

                Michael,

                In older Volvo's 850 and 960's there is something call a power stage that controls the coils. On the 850's with a single coil, the power stage is on the ignition coil assembly Vs the 960 with direct injection no cap but 6 coils. This car has 2 power stages one for even number of cylinders and the other for the odd number.

                Since your car has miss fires on all cylinders look into this as a possibility, not sure where it might be located on your car. 960 power stage is on the intake manifold by the front and rear side.







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