[Mr. Rothstein]

Howdy,

So today I replaced the valve cover gasket, the Valvetronic motor gasket, the eccentric shaft sensor and the eccentric shaft sensor gasket.

When I put it all together again, double-checked everything etc etc, and started the engine, I got a Cylinder 4 misfire. (I have a small OBD scanner that connects to my phone via WiFi, that's how I know.) Also the "Service Engine Soon" light came on.

Moreover, it's not just a code, it actually feels like one of the cylinders is misfiring (been there, done that, I know what it feels like).

Now I know I double-checked everything, including the coils. I also know all the coils and spark plugs are brand new (replaced in October 2017).

Any idea what's causing it? Is it just the matter of resetting the computer after such major work? Or is there something wrong with the coil or the spark plug?

Thank you!

[Jake_Petersen_E91]

What app are you using? I've used DashCommand before and that one works okay but it doesn't do much for clearing codes. I would recommend Carly for BMW. It's $50 on the app store and there's a $70 OBD2 connector you need to buy as well. This app will clear the code for sure, if it is just as simple as that. If the code clears, drive it and see if it comes up again. If it does, you have an issue somewhere, if not I would say you're good to go. Or there's always the option of taking it to the mechanic to clear the code however, I would recommend the Carly App setup. The idea behind the app and OBD2 connector they make is that you won't ever have to go to a BMW dealer again to have codes read or comfort access settings changed. I wish you the best of luck!

[simplesilver]

I bought an awesome code scanner last year when I bought my 328i but this is isn't about me... Well go and and triple check your coils and coil connections.... If all seems good then maybe swap coils #1 and #4. If the problem persists on #4 then it might be the plug at #4 but if it moves to #1 then the coil is the problem which is now easier to access. Good luck!

[Bimmer Pleaser]

Take the spark plug and coil#4 out and make sure they are not oily, if they are you must have rolled the new gasket, you need to redo the entire job.
If they are not oily, swap #4 and #5 coils/plugs and see if misfire moves to another cylinders. If it does, you have bad coil/plug. It is entirely possible for brand new coils to fail immediately. Happened to me.

[Mr. Rothstein]

Okay. I think the problem is electrical. Every time I put a new coil in Cylinder 4, it just fries it. As if there were a short somewhere that somehow affects cylinder 4. (I know it fries the coil because every time I swap coils between cylinders, both of these coils are dead. And I changed the spark plug in the cylinder, just in case.)

I'm going crazy with this. Does anyone have any idea what might be causing it? I've doublechecked every connection everywhere and I can't figure it out.

I spoke to a mechanic who himself owns a BMW, he thought that I might've not timed the Valvetronic motor right or something, whatever that means, and that can be causing a cylinder misfire. But that wouldn't explain why it fries the coil every time, would it?

Thank you all very much!

[Bimmer Pleaser]

Your coils do not touch anything inside the engine, they merely increases the 12v battery voltage being fed to spark plugs. I think the problem is upstream to the coils. Make sure you dont have any loose wires (12v, ground), connectors, etc

[2BIG4A3]

OP, did you ever get to the bottom of this problem. I have the same thing on the same cylinder (and 5). Plugs coils new. Swapped coils, still misfired
Regapped plugs, still misfires. Going to try moving the plugs next, but if you discovered something perhaps I could forgo that.

Thanks