An Intricate Misfire.

I'm just trying to gain as much information as possible before committing.

It's inevitable that I have to take it to get fixed since I'm too much of a novice to figure it out...
But I'd like to get as much insight as possible so they can't feed me bull **** when the time does come.

so you're getting a check engine light... which indicates cyl6 misfire... why dont you start with that.

try swapping coils and see if the misfire follows.

yes you can check to see your adaptation values but if the car was running that lean it would have set adaptation codes already and you'd be running rough at all times.

Originally Posted by DSXMachina

You had all those codes because your voltage dropped below about 10 volts at some point. That'll light up everything including the ABS/DTC/DSC Christmas tree.

You will be going without a car soon, one way or another.

or he installed/uninstalled the JB4 before the dme went to sleep. unplugging the DME while its still awake will make it unhappy

Originally Posted by Hemorrhage

Instead of pulling the intake...
Couldn't you just spray seafoam or whatever into the throttle body?

NO
there is no magical shortcut.
nothing you spray into the engine is going to do much other than lighten your wallet. and create a noxious cloud of smoke that the people around you will not be happy about.

if your valves are carbon crusted, the only way to clean them is to mechanically do it. best way is by a walnut shell blasting, distant second best way is with brass brushes and alot of solvent.

Originally Posted by Orient330iNYC

or he installed/uninstalled the JB4 before the dme went to sleep. unplugging the DME while its still awake will make it unhappy

After installing the JB4 (or lack of), I started the car and the car went crazy. I think every light came on, and it shook like a mother ****er.
Turns out, I forgot to plug the actually JB4 box in...
At first, I thought that was the component that went into the computer, for some reason...(to do CSV logs and such).

I'm hoping that's what caused those codes...and not the strain that was put on the drivetrain with the tune in.

So, I took my car to BMW last week.
They were baffled.
But, I guess it's understandable if you can't replicate the problem on command.

I brought up the idea of built up carbon in the intake valves. They were pretty certain that that is what's causing it, but they weren't able to pull the intake manifold and verify it.
They mentioned that if that IS the problem, it wouldn't be covered under my warranty. So, I told them to just ignore it and asked for my car back so I could afford the bill.
Luckily, they didn't charge me for the X hours they spent messing with it.

However, I can't understand how it isn't covered under my CPO warranty. The power train is covered, and built up carbon on the intake valves is part of the engine...
Anybody know anything about that?

Originally Posted by Hemorrhage

So, I took my car to BMW last week.
They were baffled.
But, I guess it's understandable if you can't replicate the problem on command.

I brought up the idea of built up carbon in the intake valves. They were pretty certain that that is what's causing it, but they weren't able to pull the intake manifold and verify it.
They mentioned that if that IS the problem, it wouldn't be covered under my warranty. So, I told them to just ignore it and asked for my car back so I could afford the bill.
Luckily, they didn't charge me for the X hours they spent messing with it.

However, I can't understand how it isn't covered under my CPO warranty. The power train is covered, and built up carbon on the intake valves is part of the engine...
Anybody know anything about that?

No, but I'd read the fine print on the warranty if I were in your shoes.
There are easier ways to check the intake valves than pulling the intake manifold. In fact, I rarely would. One way is to remove the throttle body and run a borescope down the intake. The latest model has high resolution video out, and records in color. By twisting the lead as the scope passes down the manifold it is possible to access most ports and get a good idea if that's the problem.

A second way is to pass a borescope down the sparkplug hole after rotating the engine so that the intakes are open. You can then inspect the area right behind the valve head which usually has the worst accretion. Given my druthers, I'd go through the throttle body. It gives me a better look at all the nooks and crannies.

Expect to pay a couple hundred bucks for the exam it the throttle body is removed. Gaskets included.

Originally Posted by DSXMachina

No, but I'd read the fine print on the warranty if I were in your shoes.
There are easier ways to check the intake valves than pulling the intake manifold. In fact, I rarely would. One way is to remove the throttle body and run a borescope down the intake. The latest model has high resolution video out, and records in color. By twisting the lead as the scope passes down the manifold it is possible to access most ports and get a good idea if that's the problem.

A second way is to pass a borescope down the sparkplug hole after rotating the engine so that the intakes are open. You can then inspect the area right behind the valve head which usually has the worst accretion. Given my druthers, I'd go through the throttle body. It gives me a better look at all the nooks and crannies.

Expect to pay a couple hundred bucks for the exam it the throttle body is removed. Gaskets included.

I looked over the "what's not included" section of the CPO warranty.
Can't say I found a concrete statement saying why it isn't covered.

Originally Posted by DSXMachina

There are easier ways to check the intake valves than pulling the intake manifold. In fact, I rarely would. One way is to remove the throttle body and run a borescope down the intake. The latest model has high resolution video out, and records in color. By twisting the lead as the scope passes down the manifold it is possible to access most ports and get a good idea if that's the problem.

----

Expect to pay a couple hundred bucks for the exam it the throttle body is removed. Gaskets included.

What boroscope are you using; whatsa resolution? Wireless comm?

OP, on the second para, don't neglect the relatively easy DIY - I've received the BMW parts from Tischer in anticipation of reaching 60k mi some day.

Originally Posted by CALWATERBOY

What boroscope are you using; whatsa resolution? Wireless comm?

OP, on the second para, don't neglect the relatively easy DIY - I've received the BMW parts from Tischer in anticipation of reaching 60k mi some day.

Oh, I definitely plan on doing it myself now that I have a pretty good idea that that is the problem.
I'm just not understanding why it's not covered.

Another thing I don't understand is...why would carbon build up cause a misfire?
I've also been paying attention to the problem and found something else out...why would it only happen at full operating temperature?

Originally Posted by Hemorrhage

Oh, I definitely plan on doing it myself now that I have a pretty good idea that that is the problem.
I'm just not understanding why it's not covered.

Another thing I don't understand is...why would carbon build up cause a misfire?
I've also been paying attention to the problem and found something else out...why would it only happen at full operating temperature?

Poor seal; obstruction to flow.

Did I post this?

Originally Posted by CALWATERBOY

Poor seal; obstruction to flow.

Did I post this?

Yes. I have it saved for when the time comes. Thanks.

Is this a problem on all turbo'd+fuel injected engines? Or is it just another problem on the N54 platform?

Originally Posted by Hemorrhage

Yes. I have it saved for when the time comes. Thanks.

Is this a problem on all turbo'd+fuel injected engines? Or is it just another problem on the N54 platform?

An issue with all directly injected engines as, unlike other config's, fuel does not wash the intake valves. Likely source of coke: PCV

Originally Posted by CALWATERBOY

What boroscope are you using; whatsa resolution? Wireless comm?

OP, on the second para, don't neglect the relatively easy DIY - I've received the BMW parts from Tischer in anticipation of reaching 60k mi some day.

Snap-On, second gen. with optional extended length probe. Unsure of resolution, easily able to see 1/32" objects though. Not wireless though some of my tools are Bluetooth. This one has the screen on it.
Snap-On now has a remote screen, Bluetooth enabled borescope but I would have no use for it.