E320CDI 2008 (OM642): Terrible running following EGR replacement

[W1llC]

Hi all,
Really hoping that someone can guide me or advise.
I have a 2008 ('58 plate) E320CDI estate (W211) fitted with the OM642.920 engine and with roughly 140,000 miles on the clock.
I'd been suffering from the well-documented (but seemingly poorly understood) issue of code 2511-001 (Check Component Y27/9 (Left EGR positioner) - Positioner signals fault) inducing limp-home mode. Stopping the car and restarting would temporarily clear the issue before it returned, seemingly at random and whenever it felt in the mood; which was regularly. Other than that, the car ran fine!
I therefore decided to replace the EGR valve. I used a refurbished Whaler unit from a well-respected dealer.
I performed the replacement myself and experienced no issues or difficulty with the actual work. Unfortunately, the new EGR valve had an immediate and very obvious negative impact on the car's running, and it has performed like a dog's dinner ever since! The low-speed regime (eg urban and town driving) is the worst, with surging, kangarooing, hesitation, audible turbo fluttering (with associated jerkiness, a bit like repeatedly stabbing the throttle two or three times a second) and general lack of power. The medium speed regime (cruising around 40-50 mph) is slightly better, but still subject to hesitation and accompanied audible turbo flutter and on/off modulation). Motorway cruising at 70mph is better, but by no means perfect. The same error code is still being generated (2511-001) and sometimes 2355-002 (EGR: Air mass is too large).
When cruising (or more accurately "painfully stuttering") in the low-speed regime, suddenly flooring the throttle causes the car to take off like a rocket, and accelerating at motorway speeds is effortless, so I'm reluctant to blame the turbo. However, I could be wrong.
Temperature (both engine and environmental), engine running time and road gradient all seem to have no bearing on the issue, although it seems to run ok from cold for literally a minute. Maybe two.
I'm aware of the usual suspects, so here's what I've done. I've had the turbo actuator apart, and visually inspected, prodded and tested all of the usual broken wire failure points. All wires are firmly in place and all wiring paths show full continuity from the circuit board to the external connector plug. The mechanical gears and linkages are free of debris and I've greased them with the recommended grease. I've also recently acquired a Mercedes STAR diagnostic system and I've used it to test the turbo actuator. It passes all tests.
The EGR valve passes all STAR diagnostic tests.
The Exhaust Back Pressure sensor is clean and passes all tests.
During diagnosis for the original limp-home fault, I performed the resistor bypass on the suspected swirl flap motor. That bypass is still in place.
Tests on MAF and other sensors are all good.
I've checked for air leaks around the turbo and the intercooler pipes and I've replaced the crankcase PCV valve and hosing. I've replaced the red turbo inlet seal (being careful to avoid kinks in the rubber) and the red PCV connection seal.
If I disconnect the EGR (electrically), the problem goes away, albeit with slightly reduced power and responsiveness over a fully-functional engine. But this is still vastly preferable to the situation with the EGR connector in place! I appreciate that this experiment doesn't necessarily implicate the EGR (despite the other evidence).
The only thing I can think of is that the replacement EGR is the wrong type. I read on another forum that the pre-2006 models (642.211 engines) had a known EGR fault, the cure for which was to fit a newly updated model of the EGR valve and perform an engine ECU flash to updated firmware. (The Dealer Technical Bulletin actually mentions the presence of the two faults I'm seeing, along with "surging/hesitating/misfiring at part load, which is exactly what I'm experiencing). I'm aware that my car has a different engine to that described in the DTU, and I'm assuming that my 2008 car has any associated ECU firmware updates appropriate to its year of manufacture. but is it possible I've fitted an EGR valve conforming to the pre-2006 build, and therefore incompatible at a code level? STAR makes no reference to EGR valve coding and there is no EGR adaption procedure to follow.
Software/firmware incompatibility would certainly explain the diagnosis issues I'm having, but then I might have missed something!
Any thoughts/suggestions? I'm not claiming to be an expert and I'm open to any suggestions or even well-intentioned ridicule! (haha). I'm not an expert with STAR either, so please don't assume that I've ran all applicable tests, or indeed know how to fully interpret the results.
I could of course replace the EGR valve again, but I don't want to keep throwing money at the car without solid diagnostic evidence to support the purchase of new parts.
I guess an independent specialist is my next option.
Thanks for reading.

 

[Uncle Benz]

Do you still have the original EGR valve that you removed?

 

[W1llC]

Do you still have the original EGR valve that you removed?

A valid question, but unfortunately not. Figuring the situation couldn't get any worse than it was at the time (I was wrong of course!) I pulled it apart in the name of science, to see if I could see anything obviously wrong with it, a process that rendered it unusable. So I disposed of it.

 

[Uncle Benz]

Bugger. It will not go down well with some on here, but a delete of the EGR functionality via remapping may be useful, even if only as a diagnostic tool to establish if the replacement EGR valve is indeed the culprit. There are a few experts about with the ability to do this. Whereabouts are you located?

 

[W1llC]

Yeah, I would happily have reinstalled it for troubleshooting purposes. I do, though, have photographs of the original EGR and its serial numbers etc. Service records show that that EGr was replaced before I acquired the car (I've had if for 6 years now) so I'm pretty sure that the EGR valve I removed was not the original. Perhaps that valve (the one that I removed) was also incompatible with the car, given the symptoms. I'd previously cleaned and mechanically checked it (but couldn't give it a full diagnostic workout because I didn't have STAR at that point) but it never resolved the problem.

I'm based in Leighton Buzzard (basically, Milton Keynes)

 

[Uncle Benz]

Anthony at GAD Tuning is capable of coding out the EGR functionality for diagnostic purposes, or more. He’s in Burnham On Crouch, but will travel. My pal Dale at Horsham Tuning has the same skills, but you’d have to go to him. There will be others, but these are my go-to guys for remap work. Both experts in this field

 

[W1llC]

Thank you, very much appreciated

 

[Doug1234]

Disconnect the actuator at the turbo and move the turbo operating rod through its complete range up and down.
Up is no boost and down is to build boost.

I have had the vanes stick on the turbo on my 06 om642 non dpf in my jeep and the turbo would stall and flutter so I had to replace it.
I drove to work during lock down for around 3-4 months with only 2k revs available before it would flutter and stall so limited to 60mph max… I had disconnected the actuator from turbo and tied turbo operating rod in the up position with some wire.
I would get random egr code pop up now and then like once or twice a week, po404 if I remember correctly using my Icarsoft bcii reader which is a Jeep dodge Chrysler Cadillac version. I think it flags the egr because it’s all to do with airflow in and out the engine and it doesn’t have a specific code or know that the vanes are stuck/ sticking

 

[W1llC]

Thanks for the info and suggestions Doug. I'll have a look at this, cheers.

 

[Wighty]

What about a used eBay egr valve to test it ? Sell it again , if that’s not it .
Anyone nearby you can borrow an egr valve from the same car for an hour ?
What About the front egr pipe that can block up , not sure if that would cause the same symptoms , mine was pretty blocked at 100k , it’s top front of the engine .
It does seem you have covered everything already though .
edit , spray a can of turbo cleaner into the front of the turbo ?

 

[W1llC]

Thanks for your reply Wighty.
The EGR pipe is something that I regularly (every year) check and clean, so I'm happy that's not the issue.
And yes, I could just get another EGR valve, just to see if it makes a difference of any kind. This is my backup strategy ... but thought I'd give the forum a go in the off-chance that someone could throw a definitive light on the subject.
The turbo-cleaner, I will give a shot Thank you.

 

[supernoodle]

Assuming it was running ok before you replaced the valve, I'd be hesitant about poking about with too much else.
Assuming it is the EGR at fault and nothing else that was disturbed in the process, hesitation and rough running suggests too much EGR.
As you have Star you must have access to a lot of live data to see what is actually happening when running.
i assume you realise EGR displaces fresh air. At idle, something in the order of 50% EGR is possible, this reduces as speed and load increases.What is happening to the air flow when the rough running is occurring? I'm sure in Star you can run an actuator test whilst running to change the position of the EGR. What happens?

 

[W1llC]

Thanks for your reply Supernoodle.
Agreed that the EGR valve is the prime suspect.
I've tried various EGR tests on STAR, all of which pass. This is the crux of the issue that I have; common sense says the EGR valve is the problem, but the tests (at least the tests that I have so far been able to perform) say otherwise.
As I said, I'm not a STAR expert; my background is in IT. There may well be other tests I can perform or live data that I can capture, but I'm not sure how to this. I'm hoping that someone familiar with both STAR diagnosis (particularly with live data capture) and the problem that I've described may be able to guide or advise.
Also, I have no-one to drive my car while I operate the STAR computer, so unless I want to risk an accident I'm limited to what tests I can perform while the car is stationary. And I suspect that putting the car under load is when the problem manifests.
I'm going to investigate the potential issue of stuck turbo vanes as mentioned previously by Doug, but meanwhile I'll have another play with STAR and see if there's anything else I can do.

 

[supernoodle]

I've not used Star, but it must have the ability to to log data which you configure whilst you are stationary. Even my £50 Autel does this. The proper name for this a Service $22 Read Data By Identifier(DID), just in case it's listed as such.

I also expect Star should allow you to see snapshot or event data that was captured with the fault. This should shows pertinent information such as speed, fuelling, air flow at the time the fault was confirmed.

 

[W1llC]

Thanks for the information Supernoodle. I'll have a look for DID in STAR. And I completely agree with you, that STAR is surely capable of live data logging. I suspect it's my ignorance that's the issue, more than STAR's capabilities. I shall delve deeper.

I forgot to mention in my previous post (and also my original post) that the engine idles perfectly. I know that a lot of o EGR problems manifest at idle, but if my problem IS the EGR, it certainly doesn't show when idling.

I've previously ran a stationary test on STAR, with manual activation. The test ran fine and the engine responded as it should.

Thanks again for your input Supernoodle. Much appreciated.

 

[w204benz]

When cruising (or more accurately "painfully stuttering") in the low-speed regime, suddenly flooring the throttle causes the car to take off like a rocket

That's probably the "emergency power" logic - the ECU interprets suddenly flooring the throttle as an emergency manoeuvre and fully closes the EGR valve for a couple of seconds - without the EGR choking the engine, you get a burst of full power.
Which suggests whatever your issue is, it is occurring between the idle position of the valve and the fully closed position. (It also gives you an indication of what you can expect from an EGR delete).

I've not used Star, but it must have the ability to to log data which you configure whilst you are stationary

You would think so, but after looking at all the available settings and searching online, I don't think it does. I would love to be proven wrong.

The only way I found to 'log' data was to display the data I want to monitor on screen, then use screen recording software while I drive. Incredibly annoying, as there is a limit to how many parameters you can have on screen at any one time.

 

[W1llC]

That's probably the "emergency power" logic - the ECU interprets suddenly flooring the throttle as an emergency manoeuvre and fully closes the EGR valve for a couple of seconds - without the EGR choking the engine, you get a burst of full power.
Which suggests whatever your issue is, it is occurring between the idle position of the valve and the fully closed position. (It also gives you an indication of what you can expect from an EGR delete).




You would think so, but after looking at all the available settings and searching online, I don't think it does. I would love to be proven wrong.

The only way I found to 'log' data was to display the data I want to monitor on screen, then use screen recording software while I drive. Incredibly annoying, as there is a limit to how many parameters you can have on screen at any one time.

It's reassuring (if not disappointing) to hear of someone else echoing my suspicions regarding STAR's data logging functionality, or lack thereof!

And thank you for the insight into the "emergency power" logic. Makes perfect sense. EGR deletion is something that I may be interested in, especially after it's been alluded to earlier in this thread.

 

[Alongwayaway]

I know this is a bit of an old post, but did you get to the bottom of the problem? I'm having exactly the same fault on my 2008 ML280 with the OM642 engine and don't want to start randomly firing the parts cannon!

 

[Wighty]

I know this is a bit of an old post, but did you get to the bottom of the problem? I'm having exactly the same fault on my 2008 ML280 with the OM642 engine and don't want to start randomly firing the parts cannon!

Code 2511-01 ?

 

[Alongwayaway]

Code 2511-01 ?

Hi Wighty, yes. I could have written the OP as it's exactly the same symptoms I have. I'm now at the point where I drive the car with the EGR valve unplugged to make the car driveable, but when I plug it back in I can hear the turbo wastegate clattering and the car bunny hops and surges once it's warm. When cold it drives ok.