Low RPM misfire ESS xpipe

[bennylagoon]

Here it is :



After searches it could be coil related too. Many posts on m3cutters talks about judder, hesitation, misfire and many problems solved by replacing one or all coils. how are your coils ? How many miles ?

Mines are the originals so around 50k miles. Time to change ?

[strokemycocktus]

Originally Posted by bennylagoon

Here it is :



After searches it could be coil related too. Many posts on m3cutters talks about judder, hesitation, misfire and many problems solved by replacing one or all coils. how are your coils ? How many miles ?

Mines are the originals so around 50k miles. Time to change ?

Thanks. It looks like the crossover palcement in your X-pipe is similar to the original one, so maybe this is not the cause for this issue.

My coils are probably original as well, 78k km so similar to yours. However from what I read the problem is usually much more complex when your coils are on the way out - rough idle and misfire on idle and throughout the rev range, not just some hesitation occuring always at specific rpm.

I got the same fault code again even though the low pressure fuel sensor is replaced. I cleared adaptations and followed BMW instructions for replacement. This started right after I installed the 100 octane stage 2 tune. Not sure how to troubleshoot it now.

Some new logs attached, they may be a bit clearer - one is low rpm 5th gear pull and the other is 3rd gear pull from 1600 to 6500rpm, both with dsc off.

I am also concerned about how my car starts with the tune, this is my cold start with a cold start delete. It sounds like it has a hard time to fire up.

I ordered a 98 octane tune and I'll let you know if anything changed with it.

[bennylagoon]

My car is a bit long to start too. Maybe related to the coils too.

Today wanted to log.. 6th gear at 50kph, floored it and the car goes to limp mode. It's the first time i have a limp mode on this car.

Here are all the codes I can read :


I'm actually on E85. I know E85 request more spark so i will test with Sp98 to see if it's better. If it is, i will begin by coils.

There are part of maintenance and important for performance anyway so no waste of money.

[SYT_Shadow]

Originally Posted by bennylagoon

My car is a bit long to start too. Maybe related to the coils too.

Today wanted to log.. 6th gear at 50kph, floored it and the car goes to limp mode. It's the first time i have a limp mode on this car.

Here are all the codes I can read :


I'm actually on E85. I know E85 request more spark so i will test with Sp98 to see if it's better. If it is, i will begin by coils.

There are part of maintenance and important for performance anyway so no waste of money.

I'd stop running E85 for starters.

[strokemycocktus]

Originally Posted by bennylagoon

My car is a bit long to start too. Maybe related to the coils too.

Today wanted to log.. 6th gear at 50kph, floored it and the car goes to limp mode. It's the first time i have a limp mode on this car.

Here are all the codes I can read :


I'm actually on E85. I know E85 request more spark so i will test with Sp98 to see if it's better. If it is, i will begin by coils.

There are part of maintenance and important for performance anyway so no waste of money.

I also read this is a good way to test the coils, it looks like you found your issue.
I have tried flooring it at 50 km/h in 6th on my 100 octane map and nothing weird happened, the car accelerated smoothly until it reached 2.5k rpm as usual. No codes, no limp mode, no weird sounds.

My car sounds like it's choking on a cold start, but it's just for the first start during the day. If I shut it off after literally 5 seconds and then crank again, it starts without choking. Maybe it is fuel related issue afterall.

Where are you going to source your coils? I have checked some local shops for BOSCH parts and they are all out of stock, but I see that most shops in USA have them. Wondering how's the rest of Europe.

[bennylagoon]

Originally Posted by strokemycocktus

I also read this is a good way to test the coils, it looks like you found your issue.
I have tried flooring it at 50 km/h in 6th on my 100 octane map and nothing weird happened, the car accelerated smoothly until it reached 2.5k rpm as usual. No codes, no limp mode, no weird sounds.

My car sounds like it's choking on a cold start, but it's just for the first start during the day. If I shut it off after literally 5 seconds and then crank again, it starts without choking. Maybe it is fuel related issue afterall.

Where are you going to source your coils? I have checked some local shops for BOSCH parts and they are all out of stock, but I see that most shops in USA have them. Wondering how's the rest of Europe.

When the engine Light happened, i was happy because i thought the diagnostic tool would give me 1 or 2 cylinders with misfires. But i have 5 ! I think it's strange that 5 coils are bad !

I've found one seller here in France Who have them in stock. Will Phone Bmw tomorrow to have a quote and compare.

[strokemycocktus]

Originally Posted by bennylagoon

When the engine Light happened, i was happy because i thought the diagnostic tool would give me 1 or 2 cylinders with misfires. But i have 5 ! I think it's strange that 5 coils are bad !

I've found one seller here in France Who have them in stock. Will Phone Bmw tomorrow to have a quote and compare.

I think I would replace all 8 coils if I got any codes like this.
BMW will charge you 3x more for exactly the same part

[bennylagoon]

Originally Posted by strokemycocktus

I think I would replace all 8 coils if I got any codes like this.
BMW will charge you 3x more for exactly the same part

Just called BMW to have the price for 8 coils. They just can't sell me the coils for the moment. They are out of order, no date of disponibility. Only place i found them is on ECS ou Turner.

Will try to exchange some coils to see if cylinders come back in misfires.

[bennylagoon]

Originally Posted by bennylagoon

Just called BMW to have the price for 8 coils. They just can't sell me the coils for the moment. They are out of order, no date of disponibility. Only place i found them is on ECS ou Turner.

Will try to exchange some coils to see if cylinders come back in misfires.

Work of the evening : Swap coils and test the car to see if the misfires folow the coils. They are not. Same tune, E85 too.

This time I had misfires on 7 cylinders. Not the coils for me, or not the coils only.

Tomorrow i will test with SP98 to see the difference.

[strokemycocktus]

Originally Posted by bennylagoon

Work of the evening : Swap coils and test the car to see if the misfires folow the coils. They are not. Same tune, E85 too.

This time I had misfires on 7 cylinders. Not the coils for me, or not the coils only.

Tomorrow i will test with SP98 to see the difference.

Were the coils and spark plugs clean? I saw a video on youtube where a guy shows everything covered in oil due to leaking valve cover gaskets. Mine were replaced 2 years ago, but they are leaking again now, on the outside at least. I am wondering how are the seals around the plugs doing.
Also, how old are your plugs?

[tdott]

Originally Posted by bennylagoon

Work of the evening : Swap coils and test the car to see if the misfires folow the coils. They are not. Same tune, E85 too.

This time I had misfires on 7 cylinders. Not the coils for me, or not the coils only.

Tomorrow i will test with SP98 to see the difference.

Loose the e85 tune if you don't like the longer cold starts, all S65s do it because our cars were not made to run E85. Overall I couldn't put up with the driveability issues so I went back to 93 tune.

[bennylagoon]

Originally Posted by strokemycocktus

Were the coils and spark plugs clean? I saw a video on youtube where a guy shows everything covered in oil due to leaking valve cover gaskets. Mine were replaced 2 years ago, but they are leaking again now, on the outside at least. I am wondering how are the seals around the plugs doing.
Also, how old are your plugs?

Plugs are 3000 kms. I didn't unmount them because they are only 3000 kms. Maybe i could unmount one to inspect.

Everything was clean, no oil or something else. All the plugs are tightened correctly too.

[bennylagoon]

Originally Posted by tdott

Loose the e85 tune if you don't like the longer cold starts, all S65s do it because our cars were not made to run E85. Overall I couldn't put up with the driveability issues so I went back to 93 tune.

Okay for the cold starts. I can understood, but for me it's not very annoying. Something strange because i have some friends with e85 tunes and coldstarts are just a little bit longer, not 5 seconds cranking like me.

What were the driveability issues for you ?

[pbonsalb]

Could the 2500 rpm dip be related to the vanos not changing properly? There are a few threads on vanos issues, but it is not a common problem. A tuner would know the rpm at which it changes — I have no idea for these cars. If you are logging, look at cam timing.

[bennylagoon]

Originally Posted by pbonsalb

Could the 2500 rpm dip be related to the vanos not changing properly? There are a few threads on vanos issues, but it is not a common problem. A tuner would know the rpm at which it changes — I have no idea for these cars. If you are logging, look at cam timing.

Yes it could be. Vanos changes about 2500rpm. Should have throwed a engine light if it had a problem.

Yesterday i drained my E85 tank and put 93 AKI (SP98 in France). Tuned the car with the original tune 241E.

No misfires recorded by the ECU and no misfires sound.

I didn't managed to log the lambda and fuel pulse for the moment, i will try tomorow with an other app.

I have logged timings and fuel pressure between 2krpm and 6krpm. Timings are about 28/31 and fuel pressure is between 4 bars and 6,5 bars. Need to log the fuel pulse and lambda but in my opinion timings and fuel pressure looks ok.

After that i will try with a stage 2 tune on 93 fuel.

[tdott]

Originally Posted by bennylagoon

What were the driveability issues for you ?

Cold Start cranking, Runs rough until warm, low rpm load would put it into limp mode if he wasn't warm enough and the car would freak out and light up the dash. Limp mode is un-driveable, was barely able to pull off the highway once.

[strokemycocktus]

Originally Posted by pbonsalb

Could the 2500 rpm dip be related to the vanos not changing properly? There are a few threads on vanos issues, but it is not a common problem. A tuner would know the rpm at which it changes — I have no idea for these cars. If you are logging, look at cam timing.

Hm, I am getting a higher reading of vanos intake at 2500 rpm. What do higher values mean? I can see that the higher it gets the lower the afr and vice versa, so I am guessing high vanos intake value = less air? This would make sense. Is there a way to test vanos? What causes such issues?

Also, I have replaced the fuel pressure sensor and I am still getting the same fault code non stop.

[Joshbot007]

I also have the alpine tune and this same problem (if it's related to the tune or not I have no idea). I have an decat armytrix x pipe and rear section, alpine stage 2 93oct, alpine DCT tune.

I only ever notice it when I want to pull out fast via the following manner. I start off somewhat easy and as soon as I get rolling (once the clutch fully engages) I floor it and the car bucks forward like the timing fell on its face from traction control (but its not traction control) for a second then takes off. I never really launch my car super hard (I try to save the clutches) but the one or two times I floored it from a stop I don't remember noticing the event (that doesn't mean it didn't happen though). But come to think of it when you floor it from a stop it drops the clutches above the 2.5k rpm point doesn't it? Not talking about launch control Im just talking about flooring it fast from a stop.

Regardless there is something going on here that probably won't be solved by any of us changing out ourhardware such as sensors, coils, or spark plugs. I'm guessing this is something to do with the xpipes flow characteristics causing a very repeatable detonation event and the timing dies to save itself. If I were to guess, this problem could potentially be solved by a change in the map (stock or tuned, it seems to happen for both from what some are reporting) by either removing timing that area, fuel change, or something else entirely.

Could it be something other than that? Absolutely, I haven't seen datalogs or other details to provide any evidence for my theory besides what I am experiencing behind the wheel. Regardless this thread has my attention, ill b waiting to see what others find

[strokemycocktus]

Could someone who doesn't experience any of this and has an aftermarket x-pipe please share their datalog with a pull starting below 2k rpm? This would be a nice place to start comparing the data we have.

Below is my latest log with a VANOS graph. Both inlet and outlet vanos go about 20% down at 2100 rpm and back up at about 4400 in this case. In higher rpm both vanos graphs go smoothly up along with the rpm.

However, in this graph you can clearly see where the acceleration slows down (the graph flattens down a bit) and this piece exactly mirrors the moment where the fuel trim kicks in (brown line, here -10,8% at the lowest point) and the fuel pulse width goes down (white line). This is obviously followed by timing being pulled, but that's more an effect rather than a cause here I think.

I don't know, it looks like the O2 sensors are getting a wrong read at this particular rpm and cause the fuel trim as the ECU sees that as the mixture being too rich, which it obviously isn't as the car looses power in the effect. It may be what Joshbot007 said, but then again why SYT didn't feel that in his car with the same exhaust setup?

BTW I am still getting 27CE code after replacing the low pressure fuel sensor. Once I get that cleared I'll probably replace the O2 sensors.

[strokemycocktus]

Update - I replaced the pre cat O2 sensors, nothing changed.
The low pressure fuel sensor probably needed some brake-in time, faults and issues associated with it went away after a longer trip. The car starts up smooth as it used to, but it still chokes at 2-2.5k rpm ONLY at WOT. Guess I'll just live with it and try to use only part throttle under 2500 rpm, it seems to be caused by the exhaust setup which I am not intending to replace.
If I ever get to go back to the stock xpipe I'll make sure to log it and share the results. If anyone has some other ideas or similar issue please share here

[tdott]

Wish we could get a tuner to chime in.

Sounds like an issue Akra xpipe had a certain rpm that some tuners offered a tune to smooth out.

[SYT_Shadow]

Soon I may be able to do a test with a car that has this issue today with tune X and see what happens with tune Y