Feel miss-fire but no code?

[GeorgeR]

I don’t drive my wife’s X6 often but have also been dealing with mis-fire symptoms. I say symptoms because I don’t get a notification and the independent service company, I use doesn’t get any codes. I’ve had all the coils and spark plugs replaced and that didn’t correct the problem. My service guy suggested I take it to a dealer and get the software updated to the most current. The dealer talked my wife, who dropped the car off, into a full diagnosis against my directions. They did finally update the software. I also have MPPK.

The dealer claimed there was a misfire code on cylinder 1 and after swapping spark plugs between 1 and 2, the mis-fire code moved to cylinder 2. They said they wouldn’t troubleshoot any further unless replacing all the brand new Bosch spark plugs with BMW OEM at an un-godly price. I declined and took it back to my BMW service guy to replace at no charge. He had been a top service tech at this same dealer before starting his own company. First, he didn’t pull any codes. Second, he swapped out both cylinder 1 and 2 sparkplugs and both he replaced looked fine.

None of this solved the problem. It still feels like it miss-fires occasionally, usually when going up hills. He thought it might be a fuel injector issue and gave me some Liquid Moly DIJection to add with the next gas fill-up. It may have helped a little, hard to be sure, but the problem still exists. I’ll try adding DIJection again after a few more fill-ups.

Any suggestions on how to resolve this? Thanks

@faboR6 https://f15.bimmerpost.com/forums/sh....php?t=1688446

@schung https://f15.bimmerpost.com/forums/sh...light=injector

[RED_Y_]

What exactly make you think there are misfires? You see RPM drop, engine sounds is uneven what are the symptoms?

[GeorgeR]

Originally Posted by RED_Y_

What exactly make you think there are misfires? You see RPM drop, engine sounds is uneven what are the symptoms?

The symptoms' "feel" like miss-fires. I don't know if that is what they are. I can try and drive the X6 more and also try and remember to look at the RPM reaction when the car engine starts to feel rough, usually when going up a hill. What RPM would be normal when going up a hill and what kind of drop would indicate a problem?

I can actually feel vibration, even as a passenger, when the engine seems to struggle.

Thanks

[RED_Y_]

I am asking because it might be just worn engine mounts giving you vibration and rough engine feel. Especially since you changed plugs and coils which are the usual suspects for the misfires.

[GeorgeR]

Originally Posted by RED_Y_

I am asking because it might be just worn engine mounts giving you vibration and rough engine feel. Especially since you changed plugs and coils which are the usual suspects for the misfires.

Unlikely. The car has been inspected by both a dealer and an independent service company that I hope would have checked that but I suppose anything is possible. It has less than 38K miles, that is low to get much engine mount wear isn't it? The symptom only seems to happen when going up hill and just feels like misfires. I'm thinking something to do with fuel injectors? Thanks.

[S EyeLand]

Could be battery, coils or O2 sensors. All easy to test.

[Sophisticated Redneck]

Possible it's your transfer case needs oil change+ recalibration. It gives a "tugging/missing" sensation that feels Alot like a misfire but you usually don't get any codes. Quite a few threads on this.

If you are certain it's a misfire, use a fox well scanner but go into the normal generic ob2 section (not the BMW selection) and you can pull up the misfire count for each cylinder since last start. It clears this misfire count automatically every time you start the engine so it's handy to see what is going on in each driving cycle.

[1norseman]

First time I had a coil issue, it felt like I had transmission issues, tugging feeling due to misfires.
I didn't get a check engine light, and dealership was stumped because of no codes. They had my car for two weeks trying to diagnose it.

Do you know what brand of coils they installed when you got the new ones?

I suggest getting new brand name coils and see what happens. Also make sure the caps are not warped. I just got a set of Bosch, where the caps were slightly warped and would not lock electrical connector in place. Had to reuse old caps.

Coils can be finicky. I also have a brand new set of "brand name" performance coils waiting on a replacement set, due to being faulty out of the box. I had such crazy misfires, it actually set codes.

[J0hnnyB0yx5m]

I just ordered the Dinan coils for 240$ couldn't beat the price any where else give them a try

[Jakesax]

Originally Posted by GeorgeR

I don't drive my wife's X6 often but have also been dealing with mis-fire symptoms. I say symptoms because I don't get a notification and the independent service company, I use doesn't get any codes. I've had all the coils and spark plugs replaced and that didn't correct the problem. My service guy suggested I take it to a dealer and get the software updated to the most current. The dealer talked my wife, who dropped the car off, into a full diagnosis against my directions. They did finally update the software. I also have MPPK.

The dealer claimed there was a misfire code on cylinder 1 and after swapping spark plugs between 1 and 2, the mis-fire code moved to cylinder 2. They said they wouldn't troubleshoot any further unless replacing all the brand new Bosch spark plugs with BMW OEM at an un-godly price. I declined and took it back to my BMW service guy to replace at no charge. He had been a top service tech at this same dealer before starting his own company. First, he didn't pull any codes. Second, he swapped out both cylinder 1 and 2 sparkplugs and both he replaced looked fine.

None of this solved the problem. It still feels like it miss-fires occasionally, usually when going up hills. He thought it might be a fuel injector issue and gave me some Liquid Moly DIJection to add with the next gas fill-up. It may have helped a little, hard to be sure, but the problem still exists. I'll try adding DIJection again after a few more fill-ups.

Any suggestions on how to resolve this? Thanks

@faboR6 https://f15.bimmerpost.com/forums/sh....php?t=1688446

@schung https://f15.bimmerpost.com/forums/sh...light=injector

I have this issue with my 2018 m50d and my main dealer and local BMW specialist cannot diagnose it.
So far it's had, new EGR, new inlet manifold and transfer case serviced 2 weeks ago.
After the service I didn't notice the tugging/missing which usually occurs at low revs regardless of speed (can happen at 30 in town or 80 on the motorway). I am now starting to notice it again.
No one can really advise where to go next. I've paid for the BMW extended warranty but my dealership are saying nothing is wrong and I can't replicate it on demand to show anyone.
It's getting to the point now where I'm thinking about getting rid, the car runs fine other than that it's just annoying that a car of this age with 39k miles on the clock should be doing it.

[Sophisticated Redneck]

Originally Posted by Jakesax

I have this issue with my 2018 m50d and my main dealer and local BMW specialist cannot diagnose it.
So far it's had, new EGR, new inlet manifold and transfer case serviced 2 weeks ago.
After the service I didn't notice the tugging/missing which usually occurs at low revs regardless of speed (can happen at 30 in town or 80 on the motorway). I am now starting to notice it again.
No one can really advise where to go next. I've paid for the BMW extended warranty but my dealership are saying nothing is wrong and I can't replicate it on demand to show anyone.
It's getting to the point now where I'm thinking about getting rid, the car runs fine other than that it's just annoying that a car of this age with 39k miles on the clock should be doing it.

As mention above but it seems to be if ignored: Check your transfer case.

Here is what happens when your transfer case goes out of calibration:

The DME asks the transfer case to set a certain torque within the internal clutch packs in the transfer case.

The servo motor in the transfer case responds and adjusts the clutch packs.

The DME then looks for a very small percentage of acceptable wheel slippage between the front and rear tires.

If this is not within spec, the DME tells the servo motor to release all pressure on the transfer case clutch packs and start over.

This entire process happens very quickly and will get stuck In a loop if out of calibration.

The rapid engagement and disengagement of front wheels creates a "tugging" or "missing sensation" that can happen at any speed.

Many threads on how to fix yourself: 30min transfer case oil change plus ISTA to recalibrate or some foxwell scanners can (530 can If memory is correct)

BMW techs are not trained to test or calibrate transfer cases. If you are not a DIY person, you MUST specifically ask them to perform recalibration test. Most will just want to sell you a new one for 8k when a simple oil change and recalibration will fix.

F15/16 owners get screwed that most transfer cases now don't have oil drain plugs so you must siphon out. Some dealers refuse to do this and just want to sell you a new one for 8k because $$$.

[GeorgeR]

Originally Posted by Sophisticated Redneck

As mention above but it seems to be if ignored: Check your transfer case.

Here is what happens when your transfer case goes out of calibration:

The DME asks the transfer case to set a certain torque within the internal clutch packs in the transfer case.

The sevro motor in the transfer case responds and adjusts the clutch packs.

The DME then looks for a very small percentage of acceptable wheel slippage between the front and rear tires.

If this is not within spec, the DME tells the sevro motor to release all pressure on the transfer case clutch packs and start over.

This entire process happens very quickly and will get stuck In a loop if out of calibration.

The rapid engagement and disengagement of front wheels creates a "tugging" or "missing sensation" that can happen at any speed.

Many threads on how to fix yourself: 30min transfer case oil change plus ISTA to recalibrate or some foxwell scanners can (530 can If memory is correct)

BMW techs are not trained to test or calibrate transfer cases. If you are not a DIY person, you MUST specifically ask them to perform recalibration test. Most will just want to sell you a new one for 8k when a simple oil change and recalibration will fix.

F15/16 owners get screwed that most transfer cases now don't have oil drain plugs so you must siphon out. Some dealers refuse to do this and just want to sell you a new one for 8k because $$$.

You mention "at any speed". Our X6 only seems to have this symptom when going up hills. Battery is fine, I have a CTEK - 40-206 MXS 5.0 I use to check and maintain it. I have new plugs and coils, had all typical fluids changed, made sure car has most current software. I can mention this to my independent tech. I don't have an extended warranty, now wishing I did but of course we didn't notice this until our warranty was up.

[GeorgeR]

Here are the technicians notes from BMW NW. I took the X6 to the independent service company after declining BMW's insistence they replace all with brand new spark plugs before they would do anymore troubleshooting. My Ind. service tech replaced the plugs in cyl. 1 and 2 even though neither plug showed any typical signs of misfires. Issue is still not resolved.

TEST DROVE VEHICLE AND FELT THAT THE ENGINE WOULD MISFIRE
SLIGHTLY UNDER ACCELERATION. PERFORMED SHORT TEST WITH NO FAULTS
RELATING TO CONCERN STORED. TEST DROVE VEHICLE WHILE OBSERVING THE
SMOOTH RUNNING AND MISFIRE VALUES. FOUND THAT CYLINDER 1 WOULD MISFIRE
HEAVILY WITH OCCASIONAL MISFIRES FROM OTHER CYLINDERS. SWAPPED IGNITION
COILS BETWEEN CYLINDERS 1 AND 2, THEN RE-TESTED. FOUND THAT THE MOST
MISFIRES REMAINED ON CYLINDER 1. SWAPPED SPARK PLUGS BETWEEN CYLINDERS
1 AND 2, THEN RE-TESTED. FOUND THAT CYLINDER 2 BEGAN TO MISFIRE
HEAVILY, INDICATING THE SPARK PLUG IS FAULTY. RECOMMEND REPLACEMENT OF
ALL 6 SPARK PLUGS DUE TO THE OCCASIONAL MISFIRES ON OTHER CYLINDERS AS
WELL. CUSTOMER DECLINED REPAIRS AT THIS TIME.

[Sophisticated Redneck]

Originally Posted by GeorgeR

You mention "at any speed". Our X6 only seems to have this symptom when going up hills. Battery is fine, I have a CTEK - 40-206 MXS 5.0 I use to check and maintain it. I have new plugs and coils, had all typical fluids changed, made sure car has most current software. I can mention this to my independent tech. I don't have an extended warranty, now wishing I did but of course we didn't notice this until our warranty was up.

What I meant by that is the "missing" can appear and disappear at any speed. It would be most noticeable uphill, however a true engine miss would also be most noticeable uphill. The lack of engine codes/check engine light however points more to a transfer case issue then an engine issue as the BMW DME is extremely sensitive to misfires and monitors it constantly. It will pick up misfires long before the human body can sense it, so a misfire you can feel, it will know about and and it will not be long before you get a drivetrain malfunction and check engine light.

An issue with the transfer case is not a engine miss even though it feels like it and you will not receive any warning or check engine light. The most you will get is a shadow code that can only be read if you use ISTA or a foxwell scanner and specifically read the transfer case. Most shops do not do this.

Even if you do not like to work on cars, I highly recommend you take control and invest in a nt530. You can easily test and re-calibrate your transfer case with this scanner plus you can read all codes and know exactly what is going on with your truck. You can also tap into the misfire counters for each cylinder with this tool and see if it is truly a misfire that is somehow not triggering a check engine light or drivetrain error.

It will save you money in the long run, shops will think twice about trying to work you over when they know you can read all the BMW specific codes they can and have a working knowledge of what is going on under the hood. Links below on a useful thread to read up and to the scanner itself.

https://f15.bimmerpost.com/forums/sh....php?t=1869424

https://www.amazon.com/FOXWELL-NT530.../dp/B07XJZ8GBW

[sukhk527]

Went through this a year ago. Turns out it was the transfer case. Fluid change and recalibration solved the issue.

[jkwhar]

Originally Posted by GeorgeR

Here are the technicians notes from BMW NW. I took the X6 to the independent service company after declining BMW's insistence they replace all with brand new spark plugs before they would do anymore troubleshooting. My Ind. service tech replaced the plugs in cyl. 1 and 2 even though neither plug showed any typical signs of misfires. Issue is still not resolved.

TEST DROVE VEHICLE AND FELT THAT THE ENGINE WOULD MISFIRE
SLIGHTLY UNDER ACCELERATION. PERFORMED SHORT TEST WITH NO FAULTS
RELATING TO CONCERN STORED. TEST DROVE VEHICLE WHILE OBSERVING THE
SMOOTH RUNNING AND MISFIRE VALUES. FOUND THAT CYLINDER 1 WOULD MISFIRE
HEAVILY WITH OCCASIONAL MISFIRES FROM OTHER CYLINDERS. SWAPPED IGNITION
COILS BETWEEN CYLINDERS 1 AND 2, THEN RE-TESTED. FOUND THAT THE MOST
MISFIRES REMAINED ON CYLINDER 1. SWAPPED SPARK PLUGS BETWEEN CYLINDERS
1 AND 2, THEN RE-TESTED. FOUND THAT CYLINDER 2 BEGAN TO MISFIRE
HEAVILY, INDICATING THE SPARK PLUG IS FAULTY. RECOMMEND REPLACEMENT OF
ALL 6 SPARK PLUGS DUE TO THE OCCASIONAL MISFIRES ON OTHER CYLINDERS AS
WELL. CUSTOMER DECLINED REPAIRS AT THIS TIME.

Hi, any update on this?

[suitedcboy]

If the plugs have more than 40K miles then they should be changed and not waste money on diagnostics. The transient misfires that will not allow DME to detect the misfiring will not go on too long before it worsens and the misfire is detected and warning light and messages appear. Transfer clutch stick/slip can go on for a long time and never get sensibly worse or give warning message and warning light. Ignition coils that fail when plug gap is too wide from too long use will sometimes "heal" for a time with new plugs and then the misfire comes back again with a code for the cylinder in most cases. The coil failure issue is why you see plugs and coils recommended to be changed together. On many makes, not only BMWs.

[F15_SGM]

Originally Posted by suitedcboy

If the plugs have more than 40K miles then they should be changed and not waste money on diagnostics. The transient misfires that will not allow DME to detect the misfiring will not go on too long before it worsens and the misfire is detected and warning light and messages appear. Transfer clutch stick/slip can go on for a long time and never get sensibly worse or give warning message and warning light. Ignition coils that fail when plug gap is too wide from too long use will sometimes "heal" for a time with new plugs and then the misfire comes back again with a code for the cylinder in most cases. The coil failure issue is why you see plugs and coils recommended to be changed together. On many makes, not only BMWs.

He just changed the plugs and coils already on another thread. Still no fix.

[tfunk88]

Originally Posted by F15_SGM

He just changed the plugs and coils already on another thread. Still no fix.

Hopefully he tries recalibrating the transfer case soon if he hasn’t already.

[F15_SGM]

Originally Posted by tfunk88

Hopefully he tries recalibrating the transfer case soon if he hasn’t already.

He said that his RPM is rough at idle. Not sure how TC could do that.

[tfunk88]

Ahhh, all I saw was the misfire going up a hill. Or maybe I’m confusing posts I’ve read lol

[yupetc]

if plugs and coils are confidently changed aren't the issue, leaky injectors will also yield a misfire-like feel, too; because of stoich ratio, a log to review fuel trim will reveal that.. Of course the whole transfer case fluid and calibration makes sense, too.