BMW Misfire : 330i Diagnosis

BMW Misfire : 330i Diagnosis

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, or P0308 are all OBD II fault codes that indicate that one or more cylinders are experiencing a misfire. BMW Misfire faults are common. If you have a cylinder misfire fault, there is a simple procedure that might be able to determine what cylinder or component is causing the issue.

BMW E90 330i N52 Misfire Front end P0302

First, if there are fault codes, (as in the case of a 2006 BMW 330i recently in the shop) use them to pinpoint the cylinder location of the misfire. If no faults are present, you can unplug either the ignition or fuel injection signal from the cylinder, while taking notice of how the engine is running. Good working cylinders will cause the engine to run rougher, or die out when the ignition or fuel signal source is removed.

BMW E90 330i N52 Misfire fault codes OBD p0302 p0300 P0128
BMW E90 330i N52 Misfire fault codes OBD p0302 p0300 P0128 p0301

Once you have determined the cylinder, now you can start diagnosis on what is causing the misfire. With a single cylinder misfire, we need to deduce what cylinder-specific component is causing the cylinder to have faulty ignition, compression, and/or fuel delivery issues. Remember, always do the easiest and quickest test sequences first, as to not waste time. On this BMW 6 cylinder N52 engine, the fuel injectors and the ignition coils are easily accessible.

BMW E90 330i N52 Misfire fault codes Replacing faulty igniton coils
BMW E90 330i N52 Ignition coil cylinder swaping

One way to determine misfire sources is to swap known good components with suspected faulty components in order to determine the cause of the fault. In the case of this 3 series with a cylinder 2 misfire, ignition coils interchange easily from cylinder to cylinder. Swap #2 coil with ignition coil #1. Clear faults and start the vehicle. Let it run for a minute or until a check engine light appears. Check memory. If the fault code moved cylinders, you have located the faulty component. If there is no change in misfire location, swap the next easiest cylinder specific component (i.e. fuel injector). If faults still remain, check compression to determine if something is internally damaged (cylinder walls, piston rings, valves, camshaft lobes etc.)

BMW E90 330i N52 Valve cover ignition coils

Once the problematic component is identified, repair or replace and you’re good to go. If you have any of these fault codes on your BMW or any other vehicle, don’t hesitate to give us a ring at 815-230-2900, or contact us through email at We’re conveniently located in the Naperville/Plainfield area of the Chicago Metropolitan suburbs.

  • Jason smith
    Posted at 14:55h, 18 January

    Hello, I’m having an issue with coil replacement on an 06 BMW 325i e90 (3.0 N52 engine) The car has 86K miles and I decided to replace plugs and coil. I did some research on the coils and I bought (online) the correct ones “Bosch” according to the car’s info and production year.
    they seemed to fit perfectly but after I installed the car wouldn’t start. After a few tries I decided to put the old ones back and they work perfectly. I tried the new ones once more and they don’t work. so i’m using the old ones right now.

    Few things I noticed is that, although they look similar physically, as in the picture above, the metal piece inside of the coil tip that connects to the spark plug is far deeper inside compared to the old one which is much closer to the tip, and no matter how much you push it down, it doesn’t reach the tip of the spark plug. so there’s no spark. the engine keeps turning but there’s no firing
    After some research online I found other people that had the same issue. some of which bought their coils at the BMW dealership. i’m in talks with the store where i got the coils, and they only say that I have the correct part and they won’t take a return.
    I just thought i’d put it out there…Any thoughts on that?

  • fluidmotorunion
    Posted at 16:15h, 01 February

    Thanks for the note Jason! We haven’t run into that issue yet so I’m not sure what the issue would be. Maybe return the coils and just try from another vendor?

  • Mike Seyed
    Posted at 14:01h, 03 March

    Hello, I have an issue with my 2010 BMW 328-i. Recently, the engine light went off, and when I scanned for a code, It gave me a misfire on cylinder #5. I replaced all spark plugs with original parts. I set the code off, started the car, and about a few minutes later, the engine light off went off again. I scanned it once more and I saw that there is a misfire on cylinder #3 this time. I swapped the coil from #3 to #2 and I reset the check engine light. I started the car again, but now this time there is a misfire on cylinder #1. What do you think could be the problem? Please get back to me whenever possible. Thank you.

  • fluidmotorunion
    Posted at 09:30h, 19 March

    Check fuel injectors and all ignition coils as misfires sometimes show up on sister cylinders in the fireing order.

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