Failing coil diagnosis using ISTA misfire detection

[yardbro]

Since about 2-3 weeks ago I began to hear a slight stutter in the exhaust on startup (both cold and warm) that kind of sounds like a misfire and can physically be felt in the car. Once the idle has come down off the initial higher RPMs it idles as normal, and the stutter is not present. I have owned this car for about 2 years now and hasn't had this issue at all in the past.

No codes or CEL pointing toward anything being wrong, but I have also begun to notice that I can feel this same little stutter while driving if I am in high gear and give it about 30-40% throttle. It almost feels as though the engine loses power for .5 seconds, and then continues accelerating as normal. This doesn't happen at all if I am in a lower gear and above 2k RPM where in this case the car pulls completely normal and no stutter present.

I have both and ICOM and ISTA+ and am fairly familiar with them both, however I've exhausted my knowledge and therefore am reaching out to the forums for some guidance. Any help or info on what I should be going after would be greatly appreciated!

https://youtube.com/shorts/5sZp8EMiM-A?feature=share

[GORDON.M3]

Yes it is, a little "muted blip" is what I call it. Is a sign of a potential bank misfire. Possibly bank 2 or 1. Whats the mileage on the coils and spark plugs? When was the last time you changed your O2 sensors? These are fairly important things that should be done preventatively.

ICOM and ISTA+ won't be able to pull much information unless the car's gotten bad enough that the DME is reporting the misfire.

[yardbro]

Originally Posted by GORDON.M3

Yes it is, a little "muted blip" is what I call it. Is a sign of a potential bank misfire. Possibly bank 2 or 1. Whats the mileage on the coils and spark plugs? When was the last time you changed your O2 sensors? These are fairly important things that should be done preventatively.

ICOM and ISTA+ won't be able to pull much information unless the car's gotten bad enough that the DME is reporting the misfire.

Thanks for the info! A little more history: when this first started happening a few weeks ago I got worried about this being an injector issue so I have just replaced all 8 this week. They were all original anyway.

I did spark plugs when I first bought the car so they are about 10k miles old, however the coils I believe are original with 110k. I would love to replace all of them preventatively but at current prices I definitely want to try to figure out which one it is if that’s what’s causing the issue haha. That Borla exhaust is literally brand new and I did all new O2 sensors with it hoping that this would somehow be related, but the issue had surfaced before I changed the exhaust and remains after the swap as well.

[Soden82]

Originally Posted by yardbro

Thanks for the info! A little more history: when this first started happening a few weeks ago I got worried about this being an injector issue so I have just replaced all 8 this week. They were all original anyway.

I did spark plugs when I first bought the car so they are about 10k miles old, however the coils I believe are original with 110k. I would love to replace all of them preventatively but at current prices I definitely want to try to figure out which one it is if that’s what’s causing the issue haha. That Borla exhaust is literally brand new and I did all new O2 sensors with it hoping that this would somehow be related, but the issue had surfaced before I changed the exhaust and remains after the swap as well.

Unfortunately I think the only way to limit it to one coil would be to wait for a misfire to register, determine which cylinder it is on, then swap it to a different cylinder and see if it follows.

[yardbro]

Originally Posted by Soden82

Unfortunately I think the only way to limit it to one coil would be to wait for a misfire to register, determine which cylinder it is on, then swap it to a different cylinder and see if it follows.

Yeah I think that’s what it’s looking like at this point. It’s definitely not bad as it’s something semi-hard to notice but now that I’ve noticed it I can definitely tell it’s there. I’m assuming that’s why the computer hasn’t picked up on it yet. I will probably pull all coils next so I can at least reseat them and check for obvious issues with resistance.

[Ervin87]

Same issue with me ended up being weak coils. It would be worse with AC on. Replace only the bad coils once you know which ones are bad.

[NiBe]

You can see misfires via OBD before DME registers them as an error. The counter gets reset every time you shutdown the car. It can be accessed via apps such as Car Scanner and many more. At least it is how it works with my non-M3 E91.

[yardbro]

Originally Posted by Ervin87

Same issue with me ended up being weak coils. It would be worse with AC on. Replace only the bad coils once you know which ones are bad.

Thanks man I’m hoping this is it. Seeing as they are original with high mileage and that it’s a very minor miss it would definitely make sense being weak or bad coils.

[yardbro]

Originally Posted by NiBe

You can see misfires via OBD before DME registers them as an error. The counter gets reset every time you shutdown the car. It can be accessed via apps such as Car Scanner and many more. At least it is how it works with my non-M3 E91.

I’ll check with my Autel and see if the misfire counter is helpful at all within global OBD. Thanks!

[GORDON.M3]

Originally Posted by yardbro

Thanks for the info! A little more history: when this first started happening a few weeks ago I got worried about this being an injector issue so I have just replaced all 8 this week. They were all original anyway.

I did spark plugs when I first bought the car so they are about 10k miles old, however the coils I believe are original with 110k. I would love to replace all of them preventatively but at current prices I definitely want to try to figure out which one it is if that’s what’s causing the issue haha. That Borla exhaust is literally brand new and I did all new O2 sensors with it hoping that this would somehow be related, but the issue had surfaced before I changed the exhaust and remains after the swap as well.

If you get access to INPA or Ista you can check the DME log history to see which if any of the cylinders are misfiring. With 110k mileage on the motor with original coils, it's safe to say its time to get new coils.

if the o2 sensors are new, then you are fine. I suspect a weak/aged coil in one of the 8 that you have.

[yardbro]

Originally Posted by GORDON.M3

If you get access to INPA or Ista you can check the DME log history to see which if any of the cylinders are misfiring. With 110k mileage on the motor with original coils, it's safe to say its time to get new coils.

if the o2 sensors are new, then you are fine. I suspect a weak/aged coil in one of the 8 that you have.

Just popped into global OBD with my Autel and found the misfire counter under one of the submenus just as NiBe mentioned. Weird that it wasn't part of live data as that was where I was expecting it to be.

I found that misfires were happening on cylinder 2 and the counter pretty accurately reflected the number of "pops" I hear on startup. Swapped cylinder 1 and 2 coils and am now seeing misfires on cylinder 1 instead of 2 although it seems to be fewer now. I attached some photos of the data for reference.

I feel pretty confident in chocking this up to be aging/dying coils that are just starting to be on their way out. Thanks so much guys I really appreciate it.

[GORDON.M3]

Originally Posted by yardbro

Just popped into global OBD with my Autel and found the misfire counter under one of the submenus just as NiBe mentioned. Weird that it wasn't part of live data as that was where I was expecting it to be.

I found that misfires were happening on cylinder 2 and the counter pretty accurately reflected the number of "pops" I hear on startup. Swapped cylinder 1 and 2 coils and am now seeing misfires on cylinder 1 instead of 2 although it seems to be fewer now. I attached some photos of the data for reference.

I feel pretty confident in chocking this up to be aging/dying coils that are just starting to be on their way out. Thanks so much guys I really appreciate it.

Yup, with that kinda of mileage, the coils were definitely due for a change. You could get away with replacing (1) but I recommend doing all (8).

[RocketyMan]

Originally Posted by GORDON.M3

Yes it is, a little "muted blip" is what I call it. Is a sign of a potential bank misfire. Possibly bank 2 or 1. Whats the mileage on the coils and spark plugs? When was the last time you changed your O2 sensors? These are fairly important things that should be done preventatively.

ICOM and ISTA+ won't be able to pull much information unless the car's gotten bad enough that the DME is reporting the misfire.

This is straight up false...as well as other's "input" to this issue.

There is a specific ISTA panel dedicated to misfire and/or knocking. You can log which specific cylinder is having the suspected problem very easily. I for one have posted this on this forum in great detail showing how I deduced which cylinder was misfiring and fixed it accordingly very easily without too much "guessing and checking."

It is only a requirement by the emissions level of a vehicle on which standard it has to follow for a "fault code" to illuminate on the dash. This is bad practice "to wait for it to get bad enough to register." No, you can look at live data to determine what is giving problems. Be smart and strategic about this...not just a part swapper. Coils for these cars are too expensive to just throw parts at. Use data for your assessment.

https://www.m3post.com/forums/showpo...50&postcount=7

https://www.m3post.com/forums/showpo...89&postcount=9

[yardbro]

Originally Posted by RocketyMan

This is straight up false...as well as other's "input" to this issue.

There is a specific ISTA panel dedicated to misfire and/or knocking. You can log which specific cylinder is having the suspected problem very easily. I for one have posted this on this forum in great detail showing how I deduced which cylinder was misfiring and fixed it accordingly very easily without too much "guessing and checking."

It is only a requirement by the emissions level of a vehicle on which standard it has to follow for a "fault code" to illuminate on the dash. This is bad practice "to wait for it to get bad enough to register." No, you can look at live data to determine what is giving problems. Be smart and strategic about this...not just a part swapper. Coils for these cars are too expensive to just throw parts at. Use data for your assessment.

https://www.m3post.com/forums/showpo...50&postcount=7

https://www.m3post.com/forums/showpo...89&postcount=9

Thanks so much this is indeed very helpful. I actually stumbled upon this function in ISTA before I posted but couldn't really make sense of what I was looking at/for. It was right about here that I decided I needed to reach out to the forums for input since I also wasn't even sure if what I had was a misfire in the first place.

Using your explanation, I am definitely going to use the ISTA function to further confirm my findings now that I understand what its showing a bit better. I also completely agree with you on parts for this car being too expensive to just fire the parts cannon at it, and this is exactly why I came here asking for some help. I really wanted to narrow this down a bit before potentially spending 2k+ on coils without even being sure that they were the issue. Luckily it seems that the misfire counter in OBD is another method that can be used in conjunction with moving a suspected bad coil around in order to narrow in on them being at fault.

I also admit that my forum search skills and patience could use a little tune-up as well

[GORDON.M3]

Originally Posted by RocketyMan

This is straight up false...as well as other's "input" to this issue.

There is a specific ISTA panel dedicated to misfire and/or knocking. You can log which specific cylinder is having the suspected problem very easily. I for one have posted this on this forum in great detail showing how I deduced which cylinder was misfiring and fixed it accordingly very easily without too much "guessing and checking."

It is only a requirement by the emissions level of a vehicle on which standard it has to follow for a "fault code" to illuminate on the dash. This is bad practice "to wait for it to get bad enough to register." No, you can look at live data to determine what is giving problems. Be smart and strategic about this...not just a part swapper. Coils for these cars are too expensive to just throw parts at. Use data for your assessment.

https://www.m3post.com/forums/showpo...50&postcount=7

https://www.m3post.com/forums/showpo...89&postcount=9

Nice, you learn something every day. This menu will come in handy for my next diagnosis on the car.
I never let anything "bad enough to register". Call me a parts swapper or however you want to call it, but I call it doing preventative maintenance.

Originally Posted by yardbro

Thanks so much this is indeed very helpful. I actually stumbled upon this function in ISTA before I posted but couldn't really make sense of what I was looking at/for. It was right about here that I decided I needed to reach out to the forums for input since I also wasn't even sure if what I had was a misfire in the first place.

Using your explanation, I am definitely going to use the ISTA function to further confirm my findings now that I understand what its showing a bit better. I also completely agree with you on parts for this car being too expensive to just fire the parts cannon at it, and this is exactly why I came here asking for some help. I really wanted to narrow this down a bit before potentially spending 2k+ on coils without even being sure that they were the issue. Luckily it seems that the misfire counter in OBD is another method that can be used in conjunction with moving a suspected bad coil around in order to narrow in on them being at fault.

I also admit that my forum search skills and patience could use a little tune-up as well

I mean when I had done the coils on my car they were just shy of $60 each new. This was several years back, it made sense to change them all.
Along with the injectors which were only $25/each.

[yardbro]

Originally Posted by GORDON.M3

Nice, you learn something every day. This menu will come in handy for my next diagnosis on the car.



I mean when I had done the coils on my car they were just shy of $60 each new. I mean this was several years back, it made sense to change them all.
Along with the injectors which were only $25/each.

hahaha yeah dude I wish. They are like $250 USD each now for the genuine ones at least :/

[GORDON.M3]

Originally Posted by yardbro

hahaha yeah dude I wish. They are like $250 USD each now for the genuine ones at least :/

I was able to get them on RockAuto when NGK first carried the OEM Eldor ones.
Then NGK switched to Made in China coils which were all messed up and didn't work properly on our cars.

[RocketyMan]

Originally Posted by yardbro

Thanks so much this is indeed very helpful. I actually stumbled upon this function in ISTA before I posted but couldn't really make sense of what I was looking at/for. It was right about here that I decided I needed to reach out to the forums for input since I also wasn't even sure if what I had was a misfire in the first place.

Using your explanation, I am definitely going to use the ISTA function to further confirm my findings now that I understand what its showing a bit better. I also completely agree with you on parts for this car being too expensive to just fire the parts cannon at it, and this is exactly why I came here asking for some help. I really wanted to narrow this down a bit before potentially spending 2k+ on coils without even being sure that they were the issue. Luckily it seems that the misfire counter in OBD is another method that can be used in conjunction with moving a suspected bad coil around in order to narrow in on them being at fault.

I also admit that my forum search skills and patience could use a little tune-up as well

Couple of things...

If you're unsure about the graphs and such, go ahead and post a picture/screenshot of the panel with your results. It might not always be intuitive enough to understand and interpret what you're looking at, BUT...BMW does (at least try) give an explanation as to what you're looking at as well as the concept in INPA as well as TIS. When you get to the point of narrowing it down, just do what I did and post a good screenshot of the data so we all can take a looksie-loo. You can also just use it to compare it as some sort of "baseline" to my own--as an example.

Another thing...
Again, you cannot rely on the "OBD counter" for a proper diagnosis.
This counter can/will reset on key-on-key-off for "misfire" based upon the emissions standard or whatever strategy for some vehicles. Another result is that some DME strategies have "frames" within the counter that reset--meaning, you can be under the threshold for the PID to flag a "misfire CEL" as per emission requirement in the event of a misfire. You won't get a "CEL" because it didn't breach the threshold yet--but still get plenty of misfire counts throughout the frames. This is where BMW's "shadow memory" can serve a purpose throughout any diag since certain emission standards are allowed to "heal" over the road. Example...you have a CEL that comes and goes maybe because of the season/temperature/time-of-day...bad gas or whichever. All of these can have an impacts/consequences on things down the line--such as your cats as an example even tho you may have never had a consistent CEL on for misfire (as an extreme example).

[RocketyMan]

Post a pic of your misfire data from ISTA. I'm curious what you see. Do it from a cold start.

[yardbro]

Originally Posted by RocketyMan

Post a pic of your misfire data from ISTA. I'm curious what you see. Do it from a cold start.

Will do. Most likely tomorrow.

[yardbro]

Originally Posted by RocketyMan

Post a pic of your misfire data from ISTA. I'm curious what you see. Do it from a cold start.

Here are the 3 captures that I grabbed with ISTA today. Cold was dead cold; engine hasn't been run for about 24 hours. This time I didn't really hear or feel any of the pops in the exhaust from inside the car and I had previously moved the coil from cylinder 2 > cylinder 1 yesterday.

Coils were left in place just as they were for the cold start, I did a key off and immediate restart, and could feel and hear intermittent popping. The final chart was after key/ignition off for about 30 seconds, could once again feel and hear the popping.

Edit: I'm dumb and forgot to include the labels below the graph for which color corresponds to what, but they appear to be the exact same as in the screenshots you shared. I have included them as a photo as well for easier reference.

[RocketyMan]

This is great stuff!..

Okay...so you can CLEARLY see CYL 1 is having very poor combustion quality--ZERO.
This means the cylinder is straight-up not firing. But based upon your graph, I count nearly 7 misfires. You should've noticed this too while sitting in the car as it was running.

This is information on what the data means.
https://www.m3post.com/forums/showpo...80&postcount=3

So at this point, you can get a new coil and see if it improves (which you know it will for sure) with a retest on CYL 1.