Ongoing tales of woe - E250, W212 - Ireland

gdoyler

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E250, 2012, CDI AMG-sport
Hi all,
I lurk a lot and look for help and tips, but don't post much, but I wanted to share my sorry story with you all. Sorry for the long read, in advance.
Car: 2012 E250 diesel, W212, Blue Efficiency.

My first Merc - bought in November '16 - I loved this car (notice the use of past-tense)

Car drove like a dream for the first year I had it - 204bhp, pulled like a train everywhere, handled lovely on the 18" AMG wheels
Car originally came to Ireland from the UK with full Mercedes S.H. Only had 36K miles when I bought it.

My issues started towards the end of November 2017 (just after the warranty expired)

Initial symptoms - loss of low down power - shifting at the wrong times, always dropping gears when I wanted to accelerate, even gently. No engine management light on yet.

Into December '17 - engine management light comes on, no limp mode.
Showed 3 faults - I can't remember the codes, but 2 of them were: "Wastegate Actuator for low-pressure turbo does not close", and "Wastegate for low-pressure turbo is jammed" (or similar)

I went independent, in the hope of avoiding really high Mercedes service prices.
Was waiting a while to get this into mechanic, and then Christmas/New Year happened - car started intermittently going into limp mode
Meanwhile, DPF wasn't regenerating properly, so got blocked. First mechanic looked at faults but focused on the DPF - forced regen, and replaced DPF pressure sensor

Didn't clear the initial fault, and light was soon back on, and car was in limp mode 100% of the time.
This particular mechanic had some personal issues going on, so couldn't help further with the car, so I went to my old mechanic - independent, but I trust them.
They initially suspected an air leak somewhere.
We're around end of February at this stage.
Got smoke test done on car and it showed cracked intake manifold (my worst fear, having read on some forums that this was relatively common)
Got intake manifold replaced, as well as various seals on different pipes, etc, and the mechanic did timing chain while doing the job.

I have car back now for 2000 miles. No more engine management light, no more fault codes, and no more limp-mode.
Car still is not right though

Current issues:

- Horrible fuel economy - I've averaged 40mpg for last 2000 miles (where for the 22000 miles before the issues showed up - my average was always 46.3 to 47.1mpg)
- No low-down power at all. I have all the top-end power when I need it, but when I ask for low down power - no boost or drive, and car is always dropping a gear, even when accelerating gently
- Car no longer feels like a 204bhp car at all, not responsive, particularly at low revs, but even when revving through the gear box - I have power at the top-end but it doesn't feel like it used to.

I'm not a mechanic, but my thoughts are that the initial issue about the wastegate actuator was never sorted, and this is still not closing fully, so any boost from the 'low pressure' turbo is simply going out the wastegate, and I'm not getting this drive.
I've had this on Bosch and Star systems in the last couple of weeks, and it's not showing up any faults at all.

Has anyone got any advice/ideas? Am I thinking along the right track about the Wastegate actuator?

Just FYI - next step is - car is booked into official Mercedes dealer in 2 weeks for 'full' diagnostic - I told them there's no faults showing up, but they said they'd do live-data diagnostics. I'm hoping they'll find the issue, but I'm at my wits end here.
the repair bill so far has been close to eur€3K, and car still isn't right.

That's my sorry story - thanks for reading,

Gary.
 

Mr Filipov

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My initial guess is as yours. There is no mention of the turbo actuator getting fixed anywhere.

With yours being a twin turbo setup, my guess is a problem with the small one. Like you say, no boost low down.

This is something to get looked at definitely. Once that is sorted, hopefully all will be well again.
 
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gdoyler

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E250, 2012, CDI AMG-sport
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My initial guess is as yours. There is no mention of the turbo actuator getting fixed anywhere.

With yours being a twin turbo setup, my guess is a problem with the small one. Like you say, no boost low down.

This is something to get looked at definitely. Once that is sorted, hopefully all will be well again.


Thanks Mr Filipov,

I was thinking along the same lines. Any idea why this wouldn't show up as a fault then? The actuator is vacuum driven - I am assuming (someone pls correct me if I'm wrong) that when vacuum is applied - it closes? And then vacuum is reduced or cut-off to allow it to open to bleed off excess boost? Really hoping that Merc garage can show through live data if this is what's happening and then at least work towards a fix
 

Mr Filipov

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2017 BMW 535d Gran Turismo
Thanks Mr Filipov,

I was thinking along the same lines. Any idea why this wouldn't show up as a fault then? The actuator is vacuum driven - I am assuming (someone pls correct me if I'm wrong) that when vacuum is applied - it closes? And then vacuum is reduced or cut-off to allow it to open to bleed off excess boost? Really hoping that Merc garage can show through live data if this is what's happening and then at least work towards a fix

It should be showing up, so no idea why it wouldn’t. Some cars have it actuated woth vacuum, others electronically. Unfortunately I don’t know which type your is, and can’t be of much further help than siggesting to look at the turbo.

Apologies for that.
 
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gdoyler

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E250, 2012, CDI AMG-sport
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Hi all,
I wanted to add an update on this in case anyone faced similar issues in the future

Car is now 100% sorted
The underlying issue turned out to be a sticky EGR valve
No idea why it never showed anything on diagnostic but my mechanic asked around for advice and someone had a Saab TTiD with very similar symptoms and that was the cause
They checked mine - got it out- it was crudded up a bit
Cleaned it (soaked overnight in some solvent) and all put back together and car is perfect

So - if anyone gets similar symptoms to what i experienced - this could be a relatively simple fix
Another mechanic suggested that the EGR could have been the issue all along and back pressure from that could have caused the intake manifold to crack?
I have no idea but it was a horrible time - 7 months of hassle and a lot of €€€ but finally fixed



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ernieh

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Audi Q2 Sport, 2022, 1.5 Petrol
Was the sticky EGR diagnosed by the MB Dealership? If not, what did they come up with on their STAR check? I also notice that the timing chain was replaced; what was the rationale behind that? Once again it seems to me that a lot of un-necessary money has been spent on your car (not your fault, mind) by people with limited knowledge.

No matter what, glad it's all sorted now and you're happy!

Ernie
 

mattkh

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A160 W168 1999 1.6
I have no idea but it was a horrible time - 7 months of hassle and a lot of €€€ but finally fixed
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Hi
Thank you for sharing it, I found it very educational.
Does anyone know if the new diesel Mercs can be put through a 'decoke' system called Terraclean.
 
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