[MegaMatt3]

Hi guys,

Well, it finally happened. I've been posting for years about what I could tell was some general drivetrain trouble. Since about 3,000 miles on the car, I've had what I would call power jumpiness, things like:

• Uneven power response under load. If I have the accelerator down at lower RPM's, the car will unevenly deliver power - add, take away, add again, with no real rhythm.
• Engine hesitation when backing off the throttle. Occasionally, the engine will hesitate and start to stall when coming off the accelerator. I haven't been able to find a pattern here, though it's usually when I've had the engine under load (accelerating more aggressively at lower RPM's)

And most recently, last summer, for several weeks my engine would start to stall and nearly die on cold starts, before catching itself at the last second and settling into a normal idle. That's documented here. The problem went away on its own as the colder months came, and had not come back yet this summer.

So anyway, I think all these problems were related, and the shit finally hit the fan yesterday. I was passing a car on the road, accelerating quickly, and all of a sudden heard a loud *POP*, followed by an immediate loss of power, to the point where I lurched forward in my seat. I honestly thought I'd blown a tire, but their pressure was fine. So I kept driving, and could tell I had basically no engine power anymore, like maybe 20% of what I normally have.

About 10 minutes later, my car alerted me with the following message, also attached as a picture (yes, I know my car is dusty. It was scheduled to be detailed today!).

"Drivetrain malfunction: Drive moderately. Maximum drivetrain output not available. Consult service center."

Other symptoms are an extreme version of the throttle jumpiness I mentioned above, particularly at slower speeds, where I'll start from a light and the car will be accelerating (much more slowly now), and the car will randomly add and take away a lot of power, which causes it to lurch. Also now, the engine will stall and die completely on cold starts unless I give it a little throttle before it has a chance to do so. And lastly, the Drivetrain malfunction message was gone after I turned off the car and turned it back on, though the check engine light *is* on. I assume the Drivetrain message would come back if I drove it for a while. Hopefully the code's stored somewhere.

So my shop is investigating, reading codes, etc. My theory is something to do with the turbo, MAFS, something like that, but I'm not really well versed in this area.

This is a '16 M235i, completely stock, with about 115,000 miles on it. I thought I'd start the saga here for the benefit of others and to see if there's any input from the group.

Thanks!

[atek]

Have you had the chargepipe replaced? Had the same thing happen and the noise was the chargepipe exploding at the TB connection. Pop the hood and look around the intake/charge pipe area.

[MegaMatt3]

No, I haven't had the chargepipe replaced, and I'll admit to you right now I don't know what that is, haha. Can you also define "TB" for me?

It's with my shop currently, which specializes in Euro imports, so I'm hoping it's in good hands. I'll make sure I pass along this info to them.

EDIT: Read a little about chargepipes, and I'm assuming TB stands for throttle body. It looks like the OEM chargepipes are pretty standard plastic versions. When you say it exploded, are you saying it just separated from the TB at the joint, or literally exploded somehow?

[atek]

Originally Posted by MegaMatt3

No, I haven't had the chargepipe replaced, and I'll admit to you right now I don't know what that is, haha. Can you also define "TB" for me?

It's with my shop currently, which specializes in Euro imports, so I'm hoping it's in good hands. I'll make sure I pass along this info to them.

EDIT: Read a little about chargepipes, and I'm assuming TB stands for throttle body. It looks like the OEM chargepipes are pretty standard plastic versions. When you say it exploded, are you saying it just separated from the TB at the joint, or literally exploded somehow?

Yes, the OEM chargepipe is made of thick plastic. Its the main pipe that connects from the intercooler to the throttlebody on the engine (TB). Known to crack or completely break (explode-because its plastic and literally blows into pieces) which is also accompanied by a loud pop under accel, and then loss of power. If you keep driving, the MAP sensor will be reading all sorts of crazy amounts of air, which will throw a CEL in the form of a Drivetrain malfunction. It's quite quick to spot, shouldn't take a shop long if that's the issue.

the beginning of this video showcases what happened if you want to see for yourself

[MegaMatt3]

Hi atek, thanks. You're absolutely right -- my tech called me today and said my charge pipe had completely exploded. So there you go.

My question now is whether I can attribute all the weird behavior I've had for years to something wrong with the charge pipe. Could the fitting at the lock ring have been loose all these years? Maybe there was just enough air escaping/entering that it was causing my TB to do all kinds of weird things? Again, every symptom I'm having now is just an amplified version of what I've been experiencing for years.

Now that the charge pipe has exploded, should I replace it with a metal one of higher quality? If so, any recommendations? Just looking for the best, tightest fit so I can actually experience this car the way it was intended to be experienced, which I worry hasn't ever really been the case.

[atek]

Originally Posted by MegaMatt3

Hi atek, thanks. You're absolutely right -- my tech called me today and said my charge pipe had completely exploded. So there you go.

My question now is whether I can attribute all the weird behavior I've had for years to something wrong with the charge pipe. Could the fitting at the lock ring have been loose all these years? Maybe there was just enough air escaping/entering that it was causing my TB to do all kinds of weird things? Again, every symptom I'm having now is just an amplified version of what I've been experiencing for years.

Now that the charge pipe has exploded, should I replace it with a metal one of higher quality? If so, any recommendations? Just looking for the best, tightest fit so I can actually experience this car the way it was intended to be experienced, which I worry hasn't ever really been the case.

Ok so now you know! Simple fix, I choose to go with the BMS charge pipe. High quality aluminum with a 2 piece design. Also has extra bungs for meth if you want that down the line.

The other most common one is VSRF.

It is advised to get it tuned with the aftermarket charge pipes since they allow more air volume, but some have said if you keep the stock Intake it may not need to be tuned.

[MegaMatt3]

Originally Posted by atek

Ok so now you know! Simple fix, I choose to go with the BMS charge pipe. High quality aluminum with a 2 piece design. Also has extra bungs for meth if you want that down the line.

The other most common one is VSRF.

It is advised to get it tuned with the aftermarket charge pipes since they allow more air volume, but some have said if you keep the stock Intake it may not need to be tuned.

Thanks for the advice. Can you elaborate on what you mean by "get it tuned"? Do you mean something like a JB4 tuning, or do you mean something different? I've never gone past stock, so I'm not up to speed on these topics.

[atek]

Originally Posted by MegaMatt3

Thanks for the advice. Can you elaborate on what you mean by "get it tuned"? Do you mean something like a JB4 tuning, or do you mean something different? I've never gone past stock, so I'm not up to speed on these topics.

Yes, JB4, MHD, BM3 are all forms of getting it tuned. Each slightly differ in process and result but generally regarded the same.

[MegaMatt3]

Ok, quick update. Recall that I have been having weird throttle issues forever (since around 3-5K miles on the car, and I now have 115k), and I now think it's been a loose charge pipe connection this entire time. It only took it finally exploding for me to figure it out.

My shop put on my new BMS charge pipe, and I'm no longer having weird power stutters and unexpected lag at WOT. It's not like I have a totally new car or anything, not a dramatic difference in power, but so far I haven't experience any symptoms I'd been having. The challenge now is going to be training my brain to no longer expect them. Having some anxiety while driving (never knowing when the next stutter or unexpected hesitation would be) has become a habit over the last 5 years.

So that's the good news. The bad news is I went out to my car after work yesterday and started it up (this was a cold start), and the car fumbled and bumbled, couldn't get to a normal idle, and died after a few seconds. Second start, similar, but revs eventually picked up, went too high (around 2500), then eventually came back down. Turned it off, third start was normal.

I went home, did the MAF sensor reset procedure, all went fine. Cold start this morning was normal. I hope that was the problem.

Last thing: I now have a check engine light on. I'm honestly not sure if it came on yesterday when the bad cold start happened or after I did the MAF reset at home. Would unplugging the sensor and starting the car trip a code and put on the light, or is this likely something different? I'm scheduled to swing by my shop tomorrow to have them read it (don't have my own OBD reader).

[atek]

Originally Posted by MegaMatt3

Ok, quick update. Recall that I have been having weird throttle issues forever (since around 3-5K miles on the car, and I now have 115k), and I now think it's been a loose charge pipe connection this entire time. It only took it finally exploding for me to figure it out.

My shop put on my new BMS charge pipe, and I'm no longer having weird power stutters and unexpected lag at WOT. It's not like I have a totally new car or anything, not a dramatic difference in power, but so far I haven't experience any symptoms I'd been having. The challenge now is going to be training my brain to no longer expect them. Having some anxiety while driving (never knowing when the next stutter or unexpected hesitation would be) has become a habit over the last 5 years.

So that's the good news. The bad news is I went out to my car after work yesterday and started it up (this was a cold start), and the car fumbled and bumbled, couldn't get to a normal idle, and died after a few seconds. Second start, similar, but revs eventually picked up, went too high (around 2500), then eventually came back down. Turned it off, third start was normal.

I went home, did the MAF sensor reset procedure, all went fine. Cold start this morning was normal. I hope that was the problem.

Last thing: I now have a check engine light on. I'm honestly not sure if it came on yesterday when the bad cold start happened or after I did the MAF reset at home. Would unplugging the sensor and starting the car trip a code and put on the light, or is this likely something different? I'm scheduled to swing by my shop tomorrow to have them read it (don't have my own OBD reader).

Glad to hear its fixed. I understand the paranoia/anxiety left over from prolonged an intermittent driving issues - it takes time to ease over them.

You won't notice much gains from just the chargepipe install. When you combine it with the intake and stage 1 tune = night and day difference!!

In terms of your new issue- in short, YES. Unplugging your MAF while the car is on will trip a CEL. Usually a Intake Air temp/Air flow code I think its a p0111 and p0112 (don't quote me on that part). It should clear after the DME relearns, usually around 50-80 miles, though a manual reset will also work.

Definitely get it read to make sure its not something else.

[steevcruse]

With a $90 OBD2 reader you can:

- View stats like boost pressure and oil temperature in real time.
- Log data to troubleshoot problems.
- Read/Clear CEL Codes. (These need Torque Pro app)
- Code every control unit in the car:
Angel eye brightness, seat heater temperature, brake light behavior, custom
delay for opening/closing windows/moonroof, splash screens, seatbelt
warning, and dozens of other settings (need BimmerCode app)

And you can leave it plugged in, and just access it when you want to.

https://www.amazon.com/ScanTool-OBDL.../dp/B00H9S71LW