P0301 Misfire on cylinder 1

  1. Syntek

    Syntek Senior Member

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    #1 Syntek, Aug 9, 2017
    Last edited: Aug 26, 2017
    Okay lads, I'm trying to figure out what the hell is going on exactly with this car and see if this is something simple I can fix on my own or if it's out of my control/fault and I need to warranty it out. (I've been tuned most of the time + running K&N SRI)

    Been having a misfire on cold start only. These past two days it's gotten bad enough that the CEL is now flashing on/off and going into limp mode. It takes restarting the car after it warms up a bit to get it going normal again. It's been doing this on both stock and tuned base maps. The car ONLY misfires on cold start

    First thing I did was inspect and change the spark plugs at 30,000 miles. The plugs looked normal and not fouled, no signs of soaked sparks or white ash, burning oil or carbon deposits. Didn't help. Next step is I swapped the coil with cylinder 1 and 4 and flashed the car back to stock and drove around for a bit and went home. Following morning I still got the same symptoms and P0301 still came up so that rules out if it was the tune or the coils.

    Not really sure where to go from here now or what to inspect before I call it quits and just have Honda look at it. My next step is to probably throw in some concentrated full fuel system cleaner and going to Chevron (I use shell 91 80% of the time) to rule out if it's gas related or not.

    Any ideas? Thanks

    Side Note: Big shout out to @dc2turbo for taking the time to look at my datalog. Everything looked normal to him.


    UPDATE: Honda fixed the issue and replaced the injectors under warranty. Car is fixed now and no longer misfiring.
     
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  2. dc2turbo

    dc2turbo Senior Member

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    i would put it back to stock and take it to your dealer. your car should be still under warranty unless you are well over 36k.

    did you get a datalog when it threw a cel?
     
  3. calonzo

    calonzo Senior Member

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    After swapping coils, you still got a misfire on the same cylinder? If so, it must be a bad spark plug wire.
     
  4. dc2turbo

    dc2turbo Senior Member

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    #4 dc2turbo, Aug 9, 2017
    Last edited: Aug 9, 2017
    COP dont have spark plug wire

    wonder if the ECT sensor or the wideband is reading correctly
     
  5. calonzo

    calonzo Senior Member

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    Well, it may not have a traditional spark plug wire, but there is a wire connecting to the coil. Unfortunately it is part of the wiring harness, which would be expensive to replace. Better leave it to the dealer.
     
  6. Design

    Design Senior Member

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    Few questions:
    - Mods?
    - Mileage since last oil change?

    At this point, I'm inclined to limit this to a faulty injector, though I wouldn't rule out oil consumption. And I believe Honda's powertrain covers up to 60K.

    As far as the spark plug diagnosis is concerned, my 2.3 DI turbo burned a quart every 500 miles and barely showed any evidence of ash/residue on the plugs. The cylinder however was slightly wet and darker than the others by comparison.

    I 2nd the recommendation to stock out and bring to the dealer for diagnosis.
     
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  7. OP
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    Syntek

    Syntek Senior Member

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    #7 Syntek, Aug 9, 2017
    Last edited: Aug 9, 2017
    Hondata tuned + K&N SRI for at least 13k miles without any issues (until now anyway). I'm starting to think it may be a vacuum leak somewhere (I hear a faint whistling at start up and then goes away that I can't pin point) or a fuel injector like @Design suggested. I'm at 31,300~ miles right now so have a little bit of time before it's up.

    I got my 30,000 service I'd like to say a few weeks ago. They changed out the belt, flushed CVT fluid, changed oil, etc etc etc.
     
  8. 360glitch

    360glitch Moderator
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    Out of curiosity are your MAF scaling setting adjusted for your specific intake?
     
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  9. OP
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    Syntek

    Syntek Senior Member

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    No idea. If the intake was the issue wouldn't it have came up ages ago? Seems odd the misfire is only directed at cylinder 1. I figured if it was a MAF or intake problem, I'd be getting a misfire on all cylinders or random misfire codes
     
  10. dallasjhawk

    dallasjhawk Senior Member

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    not sure if it works the same way, but people with blow off valves weren't throwing codes right away and then after repeated use they finally do
     
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  11. 360glitch

    360glitch Moderator
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    Not sure. Maybe we can get an opinion from @Hondata.
     
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  12. Shankmeyster

    Shankmeyster Senior Member

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  13. OP
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    Syntek

    Syntek Senior Member

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    Stupid question but where are the injectors located on this thing? I want to take a peek at them and do a swap to see if that may be the issue.
     
  14. Shankmeyster

    Shankmeyster Senior Member

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    I'm guessing they are in the head since it is DI.
     
  15. Design

    Design Senior Member

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    Good luck lol. They sit below the integrated IM assembly very close to the piston heads.

    upload_2017-8-9_16-49-43.png
     
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