E350Cdi - 2012 C207 - Lacking Power All of Sudden

[MrGundam]

Hi Everyone,

I recently noticed that my E350Cdi feels like it is lacking a bit of grunt / torque when accelerating hard. It has 118,000 miles.

I can't tell if it is my mind playing tricks as I only drove it locally the past 2 months and am now back to motorway driving where I can open her up a bit.

Is there anything I should start looking at that may be the cause?

I scanned for errors and nothing showed up.

A few things I initially wonder if could be causing issue:

1. About 6 months ago I changed the injector seals as one was blowing. Since then if I try and start the car immediately after putting key in, it will crank but not start. I have to turn key off and turn again and it always then fires. I now turn key to the 2nd position to prime the pump and wait about 5 seconds and then start which seems to work first time. I wonder if there is air in the fuel lines. If so could this cause lack of power when using kick down?
2. In sport mode, if I push accelerator to kickdown switch it does pull harder but the revs go very high, like it is staying in gear a long time. Is this normal or could be slipping automatic clutch plates?

This weekend I might try and bleed air from fuel lines, and check over the pressure side of the turbo seal. Any other idea?

Thanks

 

[OneForTheRoad]

1. Common issue with the older om642 engine. I had an 08 CLS that would do the same. I suspected glow plugs ,but made little difference. I did read about fuel leaking back to tank from either an injector or one of the fuel pumps,overnight. Hence the need for 2 ign cycles before starting.

2. Try holding the minus flappy paddle to overtake instead of the kick down . Just make sure to press the plus , to go back up the gears . I find the kick down on most auto's very harsh on the revs.

 

[MrGreedy]

Glow plug relay?
Search on here for some good posts.

Clogged/faulty/partially open EGR valve?
Would be able to interrogate if the EGR is not going back to zero via reasonable diagnostic e.g. iCarsoft


Air/boost leak?
Most likely culprits orange turbo seal or pipes and connections around the intercooler.

I mention the second two of the above suggestions because they are easy and cheap to check.

 

[Larkone]

1) probably glow plugs / relay
2) normal - the kickdown switch is designed to hold the gears to max revs - for overtaking etc.

check the turbo vanes and actuator are moving smoothly as well, smoke test for boost leaks (very common at that age and mileage)

 

[MrGundam]

1) probably glow plugs / relay
2) normal - the kickdown switch is designed to hold the gears to max revs - for overtaking etc.

check the turbo vanes and actuator are moving smoothly as well, smoke test for boost leaks (very common at that age and mileage)

Smoke test kit sounds like a good idea and something I have not done before. Do you recommend a type of kit suitable for this?

 

[Larkone]

Smoke test kit sounds like a good idea and something I have not done before. Do you recommend a type of kit suitable for this?

No sorry - really depends on whether you want it for a one off test or something that will last you for the future.

 

[MrGundam]

OK so bit to report on this.

I replaced the 4 red turbo intake rubber seals. The main one was pretty deformed given I only replaced it about a year ago with genuine Mercedes part.

So I replaced all 4, checked the charge pipe green seal and lower black one which were fine and put all back together.

Went for a short drive being heavy with the throttle and no different

So I plugged in iCarsoft and tried to have a look at some live data. I noticed the DPF soot content was 28.21g. The scanner never shows mine as a % or even correct mileage since last regen etc for some reason.

I took it for another hard drive and all of a sudden after several kickdown accelerations it felt more responsive and was producing some good boost(2600mbar) and torque (588Nm).

Data went from showing:

Boost pressure max :1500mbar with exhaust back pressure: 2918 when was feeling sluggish with 28 gram soot

to

Boost pressure: 2600mbar with exhaust back pressure: 1306mbar when was feeling more responsive again and only 5 gram soot

So I am starting to think it was a clogged DPF from the 2 months of driving locally on short 1 miles max trips vs my normal 60 miles a day motorway driving I am now back to. Giving it a bit of a ragging, and/or the replacement red seals seemed to have allowed it to clear.

One strange thing I noticed, and I'm not sure if it's due to my scanner is that I couldn't see any data on the EGR other than on / off ratio which never changed no matter how I drove it. Is this the EGR data stream to show how far open / closed it is? If not anyone know where to find it on iCarsoft?

Fingers crossed it is sorted now, but I am surprised / concerned how quickly the DPF clogged up from short local drives and it's drastic impact on performance. I wonder if it is a sign the DPF is on it's way out?

 

[MrGundam]

Sorry to bump this but does anyone have any experience with icarsoft and monitoring egr? My spot content is up again despite only motorway driving and the car hasn’t regen the dpf in 7000 miles.

I need to get to bottom of why it won’t regen, despite no EML.

 

[Mike1308]

I have a similar issue with e350 v6 cdi 2011, mine has 101k on the clock. On cold starts i go to turn it over and it struggles to start.when it does then manage to turn over its like its choking itself slightly and car shakes a little.someone did mention to me about the glow plug relay?? Its had a new set off plugs recently hoping that would of solved the issue but it hasnt.

I changed my 2 red seals too the one on the turbo intake and the one on the breather pipe.. as the one on the turbo intake was all out of shape and split..

Dont know what else to check..??

Recently i have noticed when starting it and letting it run theres been like white smoke and smell slightly but i dont know if that could be condensation as its been cold??

 

[OneForTheRoad]

I have a similar issue with e350 v6 cdi 2011, mine has 101k on the clock. On cold starts i go to turn it over and it struggles to start.when it does then manage to turn over its like its choking itself slightly and car shakes a little.someone did mention to me about the glow plug relay?? Its had a new set off plugs recently hoping that would of solved the issue but it hasnt.

I changed my 2 red seals too the one on the turbo intake and the one on the breather pipe.. as the one on the turbo intake was all out of shape and split..

Dont know what else to check..??

Recently i have noticed when starting it and letting it run theres been like white smoke and smell slightly but i dont know if that could be condensation as its been cold??

White smoke is unburnt diesel. Try two or 3 ign cycles before cranking over ,see if that helps , a new relay would probably help if you've changed all 6 plugs . The older om642 suffer fuel leakage back to the tank overnight and causes long cranking on morning starts .

 

[Mike1308]

Sorry bud may sound stupid when i say this..but what do you mean by 2 or 3 ignition cycles.im new to all this

 

[Gnasher141]

1,838,289 km Wow

 

[MrGreedy]

Sorry bud may sound stupid when i say this..but what do you mean by 2 or 3 ignition cycles.im new to all this

Turn to key position 2, wait for glow plug light to go out. Turn off. Turn back to position 2, wait for glow plug light to go out. Turn off. Turn back to position 2, wait for glow plug light to go out, turn to key position 3 to start the car.

New cars aside, most cars with an ignition key have three switch positions as you turn the key. You should be able to feel them with slight resistance to rotation at each of the positions. On the ignition barrel, there is usually numbering 1, 2 and 3 (or I, II and III) showing the physical position.

Not a criticism, but how have you never noticed this? I assume you must have passed your test years ago and forgotten this, which should be taught as part of learning?

 

[OneForTheRoad]

Sorry bud may sound stupid when i say this..but what do you mean by 2 or 3 ignition cycles.im new to all this

Turn key to put ign lights on wait ,turn off , repeat 3 times . Try it one morning and report back. Watch for this light .

 

[Mike1308]

Came from a 400 bhp corsa vxr bud, and never had this issue..hence the reason why i said im all new to this..

But thanks for the info ill try that for sure

 

[Mike1308]

Turn key to put ign lights on wait ,turn off , repeat 3 times . Try it one morning and report back.

By doing this..what does it do..and if it still does it what else could it be? Thanks

 

[OneForTheRoad]

By doing this..what does it do..and if it still does it what else could it be? Thanks

It warms the glow plugs a tad more and primes the fuel system.

If it's still not starting well . Try a new relay .

 

[OneForTheRoad]

Came from a 400 bhp corsa vxr bud, and never had this issue..hence the reason why i said im all new to this..

But thanks for the info ill try that for sure

Well you won't have , the Corsa was petrol and used spark plugs to start it up. Diesels require a pre heat as they start using compressed air in the cylinders ,mixed with diesel fuel.

 

[Mike1308]

Well you won't have , the Corsa was petrol and used spark plugs to start it up. Diesels require a pre heat as they start using compressed air in the cylinders ,mixed with diesel fuel.

Ok thanks for the info its a one big learning curve for me..ill try that and report back

 

[sweeper]

Sorry to bump this but does anyone have any experience with icarsoft and monitoring egr? My spot content is up again despite only motorway driving and the car hasn’t regen the dpf in 7000 miles.

I need to get to bottom of why it won’t regen, despite no EML.

I had this issue with my Viano, it was passively regening but eventually went to limp mode, the problem was faulty dpf pressure differential sensor reading 0, new one fitted and a forced active regen and it ran better than it ever had since I bought it, notably the faulty sensor didn’t bring the light on, not until it went to limp mode, fault showing was dpf blocked and pressure differential too low which is of course implausible if the filter is clogged. I used icarsoft for my diagnostics. Faulty egr should bring fault up.