2013 650i GC Re-occurring misfires

[IIMisterII]

Hello,

I am having an issue with my 650i GC with the spark plugs having to be replaced every few months. I'll be driving fine for awhile and then all of a sudden I'll get a misfire and get the DTM error and a code for a certain cylinder misfire. Once I replace the spark plug for that cylinder and clear the codes, all is well. But then a few months later it happens once again in a different cylinder, and this repeats over and over.

Fine for a couple months > Misfire > Replace that cylinder's spark plug and/or injector > Fine for a couple months > Repeat.

I'm not sure what could be causing this issue as this is my first BMW and I am new to this. I tried searching up on the forums for an answer but the problems people encounter similar to this have varying reasons as to why they're encountering them.

As a note, I have BM3 Stage 1 on 91 Octane (shitty gas where I live) and the car only has 56k miles. I had originally replaced all the spark plugs and cylinders with the NGK Iridium 1-step colder plugs before I put the BM3 tune on the car at 48k miles.

The only reason I could think that could be causing this would be either an issue somewhere within my fuel system or that I gapped the plugs incorrectly when I first replaced them. I originally gapped them at 0.022, as that was the recommendation from BM3, but now I'm thinking maybe I need to go up to something "safer" like 0.026?

Again, I'm not sure as I am still new to this car.. Any suggestions or comments would be helpful. The car's great when I'm not having misfires, but to have to deal with them every few months is a pain and the cost adds up fast.

Thanks

[Opie55]

You say you have replaced plugs and/or injectors. How many injectors and have they been correctly calibrated? What about coil packs? I can't speak to the gap with a tune but .022 sounds small.

[Mck444]

Had the same issue with you with the random misfires. Replaced the plugs with NGK Iridium(not sure gap mechanic did it). Same w/ coil packs. No issues but sometimes there would just be random misfires. Next tank of gas and then no problems. Got sick of it and just detuned the car back to stock.

[IIMisterII]

Originally Posted by Opie55

You say you have replaced plugs and/or injectors. How many injectors and have they been correctly calibrated? What about coil packs? I can't speak to the gap with a tune but .022 sounds small.

Sorry for the delay in responding, been slammed at work and didn't receive the email notification that anyone replied for some reason.

Also, I'm an idiot, had a brain-fart and said injectors instead of coils. Coils and Plugs are what I replaced initially, all of them before tuning the car. Injectors I have not replaced.

I plan on checking the gap on all the plugs on Saturday, I may change the gap to something like .026 to try and be safe and see how the car runs after that.

[IIMisterII]

Originally Posted by Mck444

Had the same issue with you with the random misfires. Replaced the plugs with NGK Iridium(not sure gap mechanic did it). Same w/ coil packs. No issues but sometimes there would just be random misfires. Next tank of gas and then no problems. Got sick of it and just detuned the car back to stock.

Can I ask what octane you were tuned for and were you stage 1 or stage 2 tune? Just trying to find commonalities to try and narrow down the issue.

I've heard that the Bootmod3 group on Facebook usually has helpful info for data logging after the tune and figuring out issues, so I might try that.

Since you tuned the car back to stock have you had any more misfires at all?

And do you not miss the power that came with the tune? I don't know if I could go back to stock and stay there with how much fun this car is tuned (when it doesn't misfire).

[Mck444]

Originally Posted by IIMisterII

Can I ask what octane you were tuned for and were you stage 1 or stage 2 tune? Just trying to find commonalities to try and narrow down the issue.

I've heard that the Bootmod3 group on Facebook usually has helpful info for data logging after the tune and figuring out issues, so I might try that.

Since you tuned the car back to stock have you had any more misfires at all?

And do you not miss the power that came with the tune? I don't know if I could go back to stock and stay there with how much fun this car is tuned (when it doesn't misfire).

I had the Bootmod3 91 octane Stage 1. Although the power was really nice, I found that on my day to day driving I never really used it that much. Sure it was nice to floor it every once in a while but I normally just cruised up to speed. Sometimes I do miss the power but the random misfires and 15mpg in the city got annoying after a while. Putting the car back to stock and probably going to look at something smaller like an M4.

[IIMisterII]

Originally Posted by Mck444

I had the Bootmod3 91 octane Stage 1. Although the power was really nice, I found that on my day to day driving I never really used it that much. Sure it was nice to floor it every once in a while but I normally just cruised up to speed. Sometimes I do miss the power but the random misfires and 15mpg in the city got annoying after a while. Putting the car back to stock and probably going to look at something smaller like an M4.

Did you have any other issues besides the misfires and bad mpg obviously?

[Mck444]

Originally Posted by IIMisterII

Did you have any other issues besides the misfires and bad mpg obviously?

Other than the misfires the only other real issue was the car burning oil like crazy. The issue is pretty well documented and it's a pretty common thing with these engines. Replaced the AC compressor because it wasn't blowing strong enough but that wasn't really a big issue.

[Onpoint79]

Question please anyone help!!! I replace coil packs, spark plugs, oil change and new o2 sensors.
Now my car is burning gas like CRAZY I drove 2 miles and the garage subtracted 7 gallons. I don't know what's going on. Only had the car for 6 months but can't enjoy smh. Can someone please shed some light on this!!!!

[Opie55]

What do you mean "the garage subtracted 7 gallons"? I don't understand what that means. If you literally burned 7 gallons in two miles I would think your car would run horribly and you'd have lots of smoke out the back. You don't say how it runs.

[Wheel man]

I had the exact same issue with misfires after replacing all coils and plugs. Come to find out I had a few bad fuel injectors. I literally had fuel pouring out of both sides of the exhaust.

[Onpoint79]

Originally Posted by Opie55

What do you mean "the garage subtracted 7 gallons"? I don't understand what that means. If you literally burned 7 gallons in two miles I would think your car would run horribly and you'd have lots of smoke out the back. You don't say how it runs.

It's runs fine just burning gas rapidly, I meant gauge sorry. I will try the fuel injectors, I mean it doesn't make sense

[jmg]

Originally Posted by Onpoint79

It's runs fine just burning gas rapidly, I meant gauge sorry. I will try the fuel injectors, I mean it doesn't make sense

Have you solved this issue? What year is your 650i?

[EngineCo345]

Just out of curiosity, what is the cost of a complete plug and coil replacement job? I know it differs between areas shops and all...just whatever you know.

[M3talllic]

I would highly recommend replacing injectors. Had the same issue with my M6 GC Comp. 6 series apparently are notorious for having high pressure fuel pumps and injectors fail due to poorish design. BMW replaced mine under warranty after they (HPFP & injectors) failed around 95k miles. Apparently these issues occurred quite often that they extended warranty for up to 120k miles or 10 years; at least for S63TUs.
More than likely this will resolve your issue.

[xmanpro]

Same happened to my 650 and 550 - bmw replaced the engine in my 650 and sent me a check to get into a M6.