[TDIwyse]

So this past week I was dealing with trying to figure out a few issues that arose all at once. Was getting a P0101 (bmw code 3FF1) error that calls out a MAF issue. And the O2 sensor data was behaving oddly. And an increased sound from the engine bay started at the same time, and boost was lower than it should've been ...

Had a spare MAF and tried that with no success. Fussed around with the O2 sensor and wiring and reset adaptations again ... and that took care of the MAF codes, but there was still a weird noise and low boost issues.

Spent a lot of time looking for vacuum leaks and pressure converter possibilities with no luck.

Double and triple checked intake track connections. Nothing.

The noise/ticking sound was coming from the vacuum pump area, but didn't see anything obvious ... at idle.

Last night I did a road test after tightening some intake track stuff, and during a full fueling pull there was a dramatic and loud change in engine noise from under hood and I lost all boost. Was pretty sure I'd be rebuilding turbo's and/or engine stuff ... Fortunately I was close to home. Limped it back to the garage (no gauge issues/lights to indicate catastrophic issues) and made sure nothing was on fire ...

Turns out it wasn't the turbo(s) or engine ... it was the flex pipe on the EGR cooler connection. It must've had a crack/tear and then finally, and catastrophically, completely separated.

http://www.realoem.com/bmw/showparts...84&hg=11&fg=50

I was basically running an open header under the hood... LOUD.

So, I hadn't seen this kind of diagnostic result for the issues of low boost, P010/3FF1, listed from my internet searches, but it's something to keep in mind as a possible reason if your aging 335d starts giving you these troubles.

Pic attached.

[kiel_dafo_kenyg_as]

Check the area where the cracked flex hose may have blown hot exhaust gas against.
Hopefully nothing is melted down.

[TDIwyse]

Originally Posted by whiteblue

Check the area where the cracked flex hose may have blown hot exhaust gas against.
Hopefully nothing is melted down.

There was some superficial damage, but nothing major.

[BB_cuda]

Glad to hear all okay with your turbos and engine.

You must have had a bending load on that flex section. I'm suggesting that at the root of the corregated flex, the bending moment fatigued and alternating stresses were at work. This would be the combo of the load and vibration which made the load oscillate.

Perhaps one of those flex/braided sections should be used to reconnect your external waste gate. I at least hope there is an extra load acting here otherwise the OEM EGR cooler could also have its flex section break. Don't think this is the case.

How was the exhaust connection repaired if it's alright to ask?

[DWR]

Just curious how the EWG is mounted.

Oh, and Happy Easter - it wasn't something worse.

[torqueisking]

Good to hear it's an easy fix.

I experienced the sample problem on the hwy at 65MPH 2hr into a road trip. The noise wasn't too bad....it was the fumes in the cabinet that were nauseating!

The X5 wouldn't go over ~40MPH with zero boost so I nursed it home with hazzards on and windows open.

Will you weld it back together or remove it?

[TDIwyse]

DWR/BB_Cuda

I "repurposed" that section from a used EGR Cooler for the EWG.

http://www.e90post.com/forums/showpo...14&postcount=3

I had an external brace on the EWG mounting that had things mounted very securely, so there was not slack/movement, at least none that I could see or initiate when pushing/pulling on it with reasonable force. Even after the flex pipe broke in two I didn't immediately notice this was the problem, as the brace was holding everything together. It wasn't until I was removing things that I noticed the black soot and then the broken flex pipe where there was a "small" gap ...

Now that I know what the problem was, I see there are a fair number of issues with cracked EGR coolers on this platform. For instance:

http://www.bimmerfest.com/forums/sho...d.php?t=696917

I noticed more diesel smell than normal this week, similar to the others in that thread, but with the deletes that smell can come into the cab as well. So it wasn't an obvious issue for me.

Planning to eliminate the flex section and go with a hardline instead for the EWG routing. In the meantime I'm back to the copper slug blocking the manifold EGR outlet. But I need to be avoid full skinny pedal due to potential overboosting with the open exhaust...

http://www.e90post.com/forums/showpo...&postcount=206

[TDIwyse]

Originally Posted by torqueisking

Good to hear it's an easy fix.

I experienced the sample problem on the hwy at 65MPH 2hr into a road trip. The noise wasn't too bad....it was the fumes in the cabinet that were nauseating!

The X5 wouldn't go over ~40MPH with zero boost so I nursed it home with hazzards on and windows open.

Interesting. So this was caused by a crack in the EGR path as well? Do you recall what error codes were thrown? Might be helpful for others to know if similar codes come up for this type of issue if they are having similar symptoms.

The interesting thing to me was that at idle, when I could be looking under the hood, I didn't see any leaks or notice the smell coming from there. It appears to have been under boost that the leak was opening up and dumping pressure. At least until the leak became BIG, and then it was so obvious even I could find it :-)

[BB_cuda]

Sorry buddy. If I came across as critical, I didn't mean too. I knew this piece came from cooler and was now being used as inlet to your waste gate. Replacing the piece with a solid piece should help. I now recall seeing Orbiter had problems with flex hoses. I believe they were called dynaflex. If they were over flexed, they could leak. I can't go into details here but wonder who Behr (EGR cooler manufacturer) sourced the hose from.

You might want to use one of braided flex pieces like we have in our down pipes for your splice. I hadn't thought that one through so take it as an idea but your the captain of this ship.

[TDIwyse]

Originally Posted by BB_cuda

Sorry buddy. If I came across as critical, I didn't mean too.

I didn't take it that way at all. It was a good comment that could definitely lead to an early fatigue failure.

Being the EGR cooler I hacked and modified was a used ebay unit, i'm not sure what it's previous life was like. It's possible the integrity of the flex pipe was already compromised before the installation and it just took a few thousand miles to surface.

[torqueisking]

Originally Posted by TDIwyse

Interesting. So this was caused by a crack in the EGR path as well? Do you recall what error codes were thrown? Might be helpful for others to know if similar codes come up for this type of issue if they are having similar symptoms.

The interesting thing to me was that at idle, when I could be looking under the hood, I didn't see any leaks or notice the smell coming from there. It appears to have been under boost that the leak was opening up and dumping pressure. At least until the leak became BIG, and then it was so obvious even I could find it :-)

My cooler was fully split apart just like yours. The DDE immediately went into limp home mode and gave me the "get it to the garage now" message. I don't remember all the error codes but "low boost" was one of them.

I had my wife hit the throttle while I stuck my head under the hood. I could see and hear the exhaust escaping from the general area. The soot made it easier to locate the exact source.

BTW, my dealer replaced the EGR cooler in my 09 335D under warranty. It didn't split but was the cause of a "bad egr cooler" code. Seems this component isn't too reliable. I'm removed it from both vehicles!

[Yozh]

TDI, I wonder if you are going to port the internal wastegate now? If you need that piece of an EGR cooler, let me know as I have a spare one. Mind you, you are probably be building a more robust piece I imagine.

[TDIwyse]

Originally Posted by Yozh

TDI, I wonder if you are going to port the internal wastegate now? If you need that piece of an EGR cooler, let me know as I have a spare one. Mind you, you are probably be building a more robust piece I imagine.

Thanks. But the pipe should be modified, with the ridged section removed, today. Hoping to get it installed tonight or tomorrow ...

[TDIwyse]

Update:

Got the hardline modification made and the external wastegate back in place a few days ago. But continuted to get intermittent O2 sensor behavior which would trigger the MAF code. The O2 behavior is used in the calibration loops for the MAF behavior. I wouldn't have thought to replace the O2 sensor without Torque/TestO which clearly showed wrong behavior from the O2 sensor (it would intermittently get "stuck" at a lambda of 1 reading no matter what was happening... and everytime this happened the P0101/3FF1 "MAF" code got triggered).

Replaced the O2 sensor and reset adaptations. Multiple drive cycles and this seems to have fixed the P0101 and 3FF1 "MAF" issue... which wasn't even related to the MAF sensor...

[DWR]

Yep, most common myth is that the codes tell you what is wrong, from the remove and replace viewpoint. Just isn't so. I think what was vexing about your problem is the O2 failed in an unusual manor. They usually die a slow dealth that can easily be detected. That's why they are good for plausibility checks against other measurements such as air flow and injector characteristics.

Love the comment about TestO because, not only am I fan of the tool and what it can tell you that so many others cannot, but I am a fan of the guy who created and continues to support it.

[BB_cuda]

One weak theory on the O2 sensor going south quickly. Gasser O2 sensors have a heater in them. When the heater fails, they start to not do so well. Sometimes thus is discovered when it gets cold for first time of season.

I come to my point. I wonder if the sudden loss of exgaust pressure made the O2 sensor start to crank away on its heater and abused itself? I say this without even knowing diesel O2 sensor has a heating element. Glad you sorted it out and only had to have the pipe repair and a new sensor.

I had obtained another salvage cooler like Yozh. I actually got it from same guy as yozh too. I got it to possibly be prepared to do external WG too. I guess I know to make cut before corregated section.

[Yozh]

Originally Posted by BB_cuda

I got it to possibly be prepared to do external WG too.

Let's be honest, you just do not want to remove the downpipe and port the internal wastegate. I think you have to remove the engine mount to do it properly

[BB_cuda]

Originally Posted by Yozh

Let's be honest, you just do not want to remove the downpipe and port the internal wastegate. I think you have to remove the engine mount to do it properly

That wasn't my motive but now that you mention it, I'm not thrilled to pull all of that back apart again. Only reason I would do that would be to have Jess straighten out my rear flange while i did that porting.

[9mmkungfu]

With the aftermarket down pipe in place, would it not be possible to do the porting without having to mess with the engine mount?

[torqueisking]

Originally Posted by TDIwyse

Update:

Got the hardline modification made and the external wastegate back in place a few days ago..

pics or it never happened

joking aside, I was initially thinking of the same solution but decided against it because I thought there's a potential for thermal induced pipe cracking without a pipe expansion joint. I'll try welding the pipe back together add still make use of the remaining expansion sections.

I look forward to hearing about how your pipe holds up.

[TDIwyse]

Originally Posted by torqueisking

pics or it never happened

joking aside, I was initially thinking of the same solution but decided against it because I thought there's a potential for thermal induced pipe cracking without a pipe expansion joint. I'll try welding the pipe back together add still make use of the remaining expansion sections.

I look forward to hearing about how your pipe holds up.

Ha. OK, here's a couple crappy pics I just snagged for you. There's still some small movement allowed with how it's in there, but I will definitely be checking it frequently ... I'm a little gun-shy of that whole area now.

On another note, I was also dealing with an intermittent issue with my H2O/methanol injection system. My flow gauge was indicating problems with it not injecting when it was supposed to, but only occasionally. Then it kept getting more frequent, and the controller started giving an "open circuit" error. So I went over all my wiring multiple times and didn't find any issues ... turns out it was the female connectors on the wire harness plug that slips into the male pins of the controller. They had started to spread a little too far over time and were not making consistent connection.

It's been like a mid-life crisis on this car this past few weeks. I'm officially tired of working on it. So I went ahead and just ordered a brand new MAF and am going to put that in as a preemptive measure against another intermittent issue...

[torqueisking]

thanks for the pics...nice work!

Electrical problems can be a really PITA... especially intermittent connections. Feels good when you find it though!