I need help. I did a complete spark plug and coil swap on my 2016 m235. Sitting at about 103k miles. This was done in prevent and the car ran perfect prior.

Now, I am having a misfire on cylinder 2 and the idle is atrocious. I have swapped coils, the misfire doesn’t follow. I swapped the new plugs back to old, same cyl 2 code and the idle is even worse.

I truly have no clue what to do at this point and don’t really understand how the car is now running like a bag of shit after it being perfect this morning.

Edit:: I’m now getting multiple misfire codes after putting all old coils and plugs back in. I’m at a total loss.

Please help me figure this out.

  • Alternative_Leader91@alien.topOPB
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    10 months ago

    None taken - you would be correct at this point I’m in way over my head. My dad has been assisting the entire time and he is extremely mechanically inclined, also at a loss. I figured I’d do the sparks and coils here that way if something did go wrong I’d have someone much better suited to help. Never in a million years did I think a simple plug and coil job would turn into this.

    I feel that we’ve done everything to potentially diagnose the issue aside from physically testing the cylinder 2 injector. From what I’ve read though, n55 injectors theoretically last 200k miles. I just find it extremely bizarre to all of a sudden shit out as a do the plugs, if an injector is the culprit.

    That’s where we’re at with it. Going to likely load it on a trailer and take it to a shop for them to deal with it and hopefully not break my bank.

    Thanks for taking the time to reply.

    • Spidaaman@alien.topB
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      10 months ago

      The injector could have been on its last leg. When was the last time coils and plugs were done? Assuming the injectors are original.

      Without having access to the tune info, it becomes a lot less simple. Have you had a shop take a look at the DME? (Maybe during the PPE?)

      • Alternative_Leader91@alien.topOPB
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        10 months ago

        Based on service history, plugs at 70k (just prior to me purchasing)

        I don’t see coils anywhere so I guess there’s chance they were original, which is partly why I wanted to go ahead and do them with the plugs.

        Bingo on the tune. I’m punching myself in the face rn over not buying my own tune the day I bought it. Boy what I would do for the info bm3 provides.

        I have not had a shop look at the DME. Suppose I should ask them to do that when I drop it off, yeah?

        • Spidaaman@alien.topB
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          10 months ago

          Yeah I would definitely let them know the deal, as much as you know. Did you just not have a PPE done before you bought it?

          • Alternative_Leader91@alien.topOPB
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            10 months ago

            Will do. Independent, no. (I know, my situation keeps looking worse).

            The dealer I bought it from (non bmw) had it serviced and prepped for sale at a neighboring bmw dealership AND did their own inspection prior to sale, so I didn’t feel the need. Lesson learned on that accord. Not worth the risk of future uncertainty.

            • Spidaaman@alien.topB
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              10 months ago

              Gotcha. Well hopefully it’s not a big deal, like just needing a new injector. Definitely see if they can help you figure out the tune/DME situation.

              And who knows, you could find a great new Indy shop near your parents for the future.