They Said it Can't be Fixed - A Journey to the Inside of a Mercedes Bluetec

In reply to Aaron_King :

I thought about that...  A couple reasons I didn't:

First of all, as it turns out, the new one is basically the same price or maybe even a little less.  So I'm not really out any significant amount of money.

Second, I don't anticipate having this beast for another two years.  At the rate I drive, that would be another 40-50k miles which would exceed the expected life of the transmission - I've got it to 167k now.

Third, I've talked to them before about a warranty replacement on an airbag and they very much didn't want anything to do with me, referring me back to my retailer.

Also, I knew with some level of certainty what Rock Auto would be able to do for me in terms of when I'll get the new one.  I was able to order it last night and get it on the way as opposed to calling Arnott today and taking however long to work through their process and their shipping times.

And finally, the worst reason, after the festival weekend, I'm just freaking exhausted so I the easiest answer is what won!

I will say, though, that the OEM strut is still on the right side.  With 167k miles on it.  And the strut that I replaced with this failed Arnott unit wasn't actually failed - turns out that one was just an oring on the air line that failed, but I went ahead with the new strut because everybody talked about how much better the Arnotts are.  The failed strut has about 70k miles on it, plus or minus.  And when the second OEM spring failed on the rear due to crappy Ohio roads, the replacement bag from Arnott failed within a month.  So I'm not convinced that these Arnott products are all that fabulous.

I can believe the Rock Auto thing.  When I did the bags on the R Class I got them directly from Arnott and in the 100K plus miles I have only had to replace one and they were great about it.

In reply to Aaron_King :

That's interesting... I didn't know Arnott sold direct!  Well, perhaps I'll file that away in case there's a next time!

In reply to wae :

The iPD heavy duty strut mounts for my Volvo sat in the "worn out" position when new.

After 120k or so, one was thoroughly broken.

I replaced it with one of the 220k mile Volvo units that I took out and saved because they sat better than the iPD ones.

In reply to Pete. (l33t FS) :

Did we reach an inflection point where the OEM parts started getting really good while the aftermarket parts just didn't?  Or did the OEM parts stay the same and the third-party stuff just took a dump?  Or is it both?

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In other news, despite creating a label for it, Rock Auto didn't actually give the strut to FedEx until this evening.  So I'm not expecting to get it until Thursday some time.  Which is putting a kink in my plans to go to Oktoberfest Thursday night.

I find that parts quality is all over the map anymore. Formerly good brands like Bosch and Febi-Bilstein and SKF are just as likely to be chicomm junk or made in DE.

OEM parts quality depends greatly on the OEM.

Chrysler parts? Junk parts for junk cars. (Sez this former ChryCo tech) 

Toyota parts? Reliable parts for reliable cars. (Sez this 30 year Toyota tech).

In reply to peanutpckrupper :

I'm about 75%/25% with them on that - usually they hit or exceed their target.  I would have just bought one locally, but FLAPS wants about $300 more for the same part number to get it today.

Last Monday we were dragging RV trailer home from NCM, and the CEL came on near the top of a long grade, as has happened several times before. Truck ran normally and now after 10 stop/start cycles the light is off. I didn't even bother plugging in scanner to find the usual "undefined" powertrain code. 

I've asked 2 of the 3 Central Ohio MB dealers to look at it, and just document the code so if the engine craps out down the line we have an idea of where to start. But they both say I need to drop it off for a few weeks until they can get to it. Translation: we don't want to touch your ancient vehicle, especially at warranty rate.

Knowing this, I thought it's time to rip up the warranty and delete some stuff. Unfortunately, while I've been futzing around with keeping it stock & running good, tunemyeuro.com has gone under, so there is no reliable US provider of such race prep service.

Humph.. .

It makes my brain hurt a little bit that the "High MIleage Award" is expressed in kilometers....

They were impressed a GL350 made it that far.

eastsideTim said:

They were impressed a GL350 made it that far.

What would be really impressive is if I could get a second one for it - 310,000 miles.  No way that could happen - I don't feel like rebuilding an OM642 again...

It is a snazzy badge though!

Almost to 175,000 miles.  I brought it in for an oil change.

It's blowing a code about the bank 1 sensor 1 O2 heater circuit so I may try another new Bosch unit in there.  There's also something going on with the air suspension in the front.  Sometimes I'll come out to the front right being down, sometimes it's fine.  It seems to be constantly trying to adjust the front height and the compressor is definitely running more than it should.  I think Xentry/DAS can do diagnostic stuff on that so I need to get my laptop, the car, and the OBD2 adapter all in the same place at the same time.

In reply to wae :

Isn't the O2 sensor still under emissions warranty?

In reply to FJ40Jim :

It would be...  But I've put over 48,000 miles on it since the emission work, so it's back out of warranty again

Hello wae, and thank you for this fantastic educational and entertaining thread! Just had to register to comment this, but probably also have a lot of questions about these engines.

I found this thread in the search for torques on the turbo and all the bolts that belong, but ended up by reading the whole tread. It gave me much valuable information on the 642 engine, but also a lot of good laughs  The highlight must have been when you wrote that the car probably during its life had leaked oil on an indian grave, nearly fell off the chair  I don`t know if you use the term "Monday car" in your country, but your car certainly deserves that label (a lousy car where new faults constantly appears). 

About the leaking air in the suspension. A couple of years ago I changed a valve block for the suspension in my car (2007 ML). It is located by the right front wheel, and is not a big job to replace. I bought a new valve block from ebay, think I payed about 150 EUR. Turned out to be a completely different fault, but that`s another story. The air suspension system is not very complicated, I think it has an undeserved bad reputation. 

My challenge is that the car goes into limp mode with two different codes on the EGR valve. In the process of troubleshooting I also discovered that the turbo is defect. It has similar damages to the turbin wheel as your  had, and I think I know why. It makes some nasty noises now... I am planning to delete the EGR function, and as the turbo needs replacing will use the opportunity to replace gaskets on the oilcooler, delete the swirl flaps, and clean up the intake manifolds and the ports on the heads. 

Last, have some patiens with the language, but I assume that you prefer bad English from good Norwegian 

I have a question for you guys. 

In november last year the car suddenly went into limp mode, and I got theese codes was on my iCarsoft code reader:

First I took out the EGR valve to clean it, but I was surprised that it barely was a thin layer of soot on it, not a lot of carbon build up, and the mecanism was sliding smoothly. 

Then I bought a new EGR valve from Autoparts. But before I replaced it I got in contact with a former colleague who is a wiz on tuning, and agreed that we would delete the EGR function, so I returned the valve. 

But as time went the symptomes from the car got worse. It started to make some nasty noises, and sometimes it felt like I had kangaroo-diesel on the tank. Whet I took of the "batwing" to replace the PCV valve, I also discovered that the turbine wheel on the turbo was destroyed. I got my hands on a used turbo that seems to be in good shape, but have not replaced it yet. As I wrote in my last comment I plan to do som more maintenance when I am down there, among other things delete the swirl flaps. 

I guess the reason the turbo is damaged is that pieces of the rubber gasket between the batwing and the turbo have come loos, an then been sucked into the turbo. It looks like the batwing was incorrectly installed last time the diesel filter was replaced. One of the rubber sleeves against the air filter box was also not in place.

Then to my question:

Earlier in this thread I read that some of you had unplugged the MAF sensors, and that the car then stayed out of limp mode. Today I decied to try that, and it worked! I didn`t even get a engine lamp in the dashboard. But of course, I got some new fault codes up (Low air flow etc.) 

So, can any of you explain for me why The car do not go in to limp mode when I unplug the MAFs? The weird thing is that all of the nasty noises also disappeared! My (unqualified) guess is to that is that the noises came from the swirl flap motor, and that it was disabled when the MAFs where unplugged. 

Ideas?

Regards, Thomas

(Lucky owner of a black Scheißwagen )

Not sure about the laws & emissions standards in your country, but in USA a vehicle goes into limp mode to prevent:

1. Damage to the engine or transmission. An example would be an engine going to limp mode because coolant temp sensor reporting 150° instead of the usual 95-100°.

2. Excessive emissions. An example is going to limp mode because of inoperative EGR or empty DEF tank.

It didn't go to limp mode when MAF is unplugged because MAF input is only used to trim the fuel map. It's common on the very similar VW TDI to reflash with a performance tune that deletes MAF input and relies only on MAP, IAT, RPM, TPS. 

FJ40Jim said:

Not sure about the laws & emissions standards in your country, but in USA ...

There are of course requirements. Every second year we have to go to an approved workshop for a "EU-test" of the car. Among the tests are emissions, but I am not certain of the tolerance limits. However, earlier today I spoke to my former college who does the tuning, and he says that I can delete the EGR, the swirl flaps, and the DPF, and still not get any problems with the limits. Have not decided on the DPF yet, but at least the EGR and swirl flap goes out. 

It didn't go to limp mode when MAF is unplugged because MAF input is only used to trim the fuel map. It's common on the very similar VW TDI to reflash with a performance tune that deletes MAF input and relies only on MAP, IAT, RPM, TPS. 

Thank you very much Jim, this was exactly what I was wondering about! Not that I fully understand all this, but I have some more to get into (I am not a car mechanic, so the abbreviations has too be looked up...).

Komodo said:

FJ40Jim said:

Not sure about the laws & emissions standards in your country, but in USA ...

There are of course requirements. Every second year we have to go to an approved workshop for a "EU-test" of the car. Among the tests are emissions, but I am not certain of the tolerance limits. However, earlier today I spoke to my former college who does the tuning, and he says that I can delete the EGR, the swirl flaps, and the DPF, and still not get any problems with the limits. Have not decided on the DPF yet, but at least the EGR and swirl flap goes out. 

 

It didn't go to limp mode when MAF is unplugged because MAF input is only used to trim the fuel map. It's common on the very similar VW TDI to reflash with a performance tune that deletes MAF input and relies only on MAP, IAT, RPM, TPS. 

Thank you very much Jim, this was exactly what I was wondering about! Not that I fully understand all this, but I have some more to get into (I am not a car mechanic, so the abbreviations has too be looked up...).

I can't help you with the Mercedes stuff, but:

MAF - Mass Airflow Sensor (as you know)

MAP - Manifold Air Pressure

IAT - Intake Air Temperature

RPM - Of course :)

TPS - Throttle Position Sensor

Basically, with a tune, instead of looking at the airflow (which on a diesel isn't a throttled/controlled amount like a on a petrol engine), it can look at the air pressure in the manifold with the intake temperature, and fuel according to what your foot is telling it to do relative to those two.    The MAF is really only to dial in/fine-tune the amount of fuel injected on a diesel, since you control the engine speed with the amount of fuel you're injecting.

On a gas engine where the throttle is literally throttling (choking off) the incoming air, the MAF (or equivalent) is really important to get good throttle response, because that lets the computer know how much air is coming down the tube, so it can get a bit ahead of it for injecting fuel.  Most of those won't run at all with an unplugged MAF, although some will but only allow, say, 2000 RPM or other failure modes, all of which are accompanied by pretty warning lights on the dash.

In reply to Komodo :

Welcome!  I can assure you that you speak (or at least write) my language far better than I can communicate in yours, so I have a great deal of respect for that.

I like the term "Monday Car".  I've not heard that before, but I may have to adopt it.

As far as unplugging the MAF sensors, I do not fully understand exactly what the computer is doing, but I think that what happens is that because there's no MAF signal, the computer goes into a "fail safe" table of some sort and stops trying to do EGR things.  Since it doesn't try to acutate the EGR valve, it doesn't blow the code that forces it into limp mode.  Now, why it won't go into limp mode with disconnected MAF sensors is a mystery to me.  You'd think that since it isn't doing EGR things at all, it would limp, considering that if it fails to do EGR things it goes into limp.  Maybe two different software development teams were working on those functions.

It's interesting that it ceased making bad noises, though.  I'd be curious to know if the noises would stop with the MAF sensors hooked up and the EGR installed but disconnected.  Or with the EGR installed and connected and all that with the variable pitch controller for the turbo unplugged.

wae said:

I like the term "Monday Car".  I've not heard that before, but I may have to adopt it.

"Monday Car" is an old expression in Norway. I guess its originally refers to that the workers had a bad hangover on Mondays, and did a lousy job building cars. Just a saying of course. But as we all know, before the CNC age, the tolerances on manufactured parts were a lot wider. And when you put together an assembly with parts that are in the wrong side of the allowed interval, the finished product may get very bad quality. So these days with modern production quality of components, Monday Cars should not be a topic. 

As far as unplugging the MAF sensors, I do not fully understand exactly what the computer is doing, but I think that what happens is that because there's no MAF signal, the computer goes into a "fail safe" table of some sort and stops trying to do EGR things.  Since it doesn't try to acutate the EGR valve, it doesn't blow the code that forces it into limp mode. 

Yes, this sounds logical for me to. 

Now, why it won't go into limp mode with disconnected MAF sensors is a mystery to me. You'd think that since it isn't doing EGR things at all, it would limp, considering that if it fails to do EGR things it goes into limp.

That one is hanging in the air. (is that an expression? )

It's interesting that it ceased making bad noises, though. 

My guess is that the unplugged MAF sensors not only tells the EGR to take a brake, it also tells the swirl flap motor that it can rest for a while. This is of coarse only guessing, but after yesterdays experience I guess that the nois came from the swirl flap system, and that carbon buildup made it impossible for the motor to set the flaps in correct position, and it therefore was flapping back and forth. A friend of mine (experienced car mechanic) listened to the engine with a stethoscope, and was relatively certain that the noises came from the turbo, and not the engine it selves. But I am not convinced. The frequency did not correspond to a turbo in my ears (which are severely damaged). The sound was like "cho, cho, cho, cho", like a bad fan belt in frequency. 

But I will plug in the MAFs tomorrow and check. If the nois returns, I can not understand that it comes from the turbo. Unless, of course, the problem is that the VGT actuator is flipping and making that noise...

I'd be curious to know if the noises would stop with the MAF sensors hooked up and the EGR installed but disconnected.  Or with the EGR installed and connected and all that with the variable pitch controller for the turbo unplugged.

If I get time for this tomorrow, I will give it a try! At least weather should be nice 

And one more thing. When I spoke to "the tuner" yesterday he said that I can choose from blinding out the EGR with a metal sheet, or remove the whole EGR valve and the EGR cooler. In the last case I have to install a tube or something to replace that part of the cooling circuit, and of course blind off the other side of the cooler where the exhoust gas goes into the blending chamber. Any thoughts about that? I my eyes it would be an advantage to get rid of the entire cooler. 

Well, I officially have 50k miles on my rebuild job:

I've got a few other things to deal with before I get in there and figure out what's up with the front air and to deal with the O2 sensor.  What's kind of funny is that when I woke up on Monday morning this week, my plan was to go over to a local dealer and try to buy a fully loaded used QX80.  It was a beautiful Hermosa Blue with a Wheat interior, a color combination that is my weakness.  But that activity will have to wait until I've found a job and in the meantime, I'm going to have to keep der Scheißwagen trundling along.

In reply to Komodo :

It seems like getting the cooler completely blocked off and sealed up would be quite a job.  I wonder how feasible it would be to thread the coolant and oil ports and put plugs in them.

wae said:

In reply to Komodo :

It seems like getting the cooler completely blocked off and sealed up would be quite a job.  I wonder how feasible it would be to thread the coolant and oil ports and put plugs in them.

I have never had these parts apart, so I don`t know. But as I see it, the EGR cooler is basically a regular heat exchanger, where the exhaust gas coming from the EGR is cooled with water. Two ports in, two ports out. So my thoughts where to bypass the water in- and out with a tube or a hose. But when I delete the EGR valve (no matter if the valve is left in the car og removed permanently), the gas part is blocked, so there should be no reason not to block the ports in both ends. I am more uncertain whether the liquid part could be blocked, or if the water flow is essential for other functions in the cooling system. Therefor the bypass tube. 

You mentin oil ports, not quit certain what you mean by that. I think there are some differences in the EGR valve on my old ML from your newer GL, but does it have oil ports? 

If you look 24:43 min. into this video, there is a water hole at right beside the big hole to the EGR. That water port is not in my car. My EGR does not have a gascet either, it only has a thin O-ring. So it should be easy to turn a plug to blind off that hole with an O-ring. 

If you look 23:31 min. into this video, you see three of the ports on the cooler. The water port on the manifold in the left part of the picture should be easy to convert to a hose nipple either by a flange, or as you propose to thread up the port with a suitable tread dimension. The gas port could be blinded with a flange, but also with a plug if the hole is circular. In the front the gas port of the exchanger goes into the mixing chamber (if I have understood the assembly correctly. That port should be easy to blind off with some sort of a plug. I have a lathe in the garage, so I can make a plug as a copy of the end of the pipe. 

But that was just some thougts, I don`t know if it is doable. 

And then a short update on the ML.

Yesterday I took out the ECU and delivered it to the tuning guy. He will put in a program he called "Eco", which should make the car run more economically, but also give it 10-15% more torque and power. 

But before I removed the ECU I did some more testing. First I drove a little trip with the MAFs unplugged, just to ensure that the noise was gone, and that it did not go into limp. And it didn`t. Then I plugged in the MAFs. The noise returned immediately, and after a coupe of kilometers it went into limp mode. I then unplugged the EGR valve (as you proposed WEA), and the car behaved similarly as with the MAFs unplugged. No problem, no lamps in the dashboard. But I got a feeling that the torque curve was somewhat different from when the MAFs were unplugged. Got a feeling that it lacked torque between 1400 and 2000 rpm, and that I had to press the pedal in the floor to make it accelerate. Then it went very high up in revolutions before it shifted down. Might just be a feeling though. 

At least I pulled out both the MAFs and the EGR, and the behavior was similar as when only one was unplugged. I did not have the time to unplug the turbo though, so that question still hangs in the air. 

At this point I am quite certain that the noise comes from either the swirl flap system, or the VGT system on the turbocharger. It was a big relief that as well the noise as the limp mode disappeared when I followed your advise to unplug the MAF sensors. This tip alone was worth reading the whole tread! It brought me a big step further in my troubleshooting. So thank you very much one more time! 

Here are two short cuts of the noise. It comes in low speed, and is present aproximotley between 1400 and 1900 rpm. 

First video 

Second video

At last I have one more question for you. The rubber parts on the underside of the engine cover are worn out. Does any of you know what they are called? I have seen a Youtube clip where a guy replaced those rubbers, but I have not found a place to buy them. The cover is totaly loose on top of the engine. 

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Edit:

Now it came in a message from the tuner. The ECU is done already, so just to come and get it. Will be exiting to see if the car runs fine with the EGR unplugged, and without fault codes. Yesterday when testing I got 11 fault codes...