CLK Running rough

[brian_H]

Morning all

Driving in to work this morning on the motorway, sitting at a 65mph cruise, I put my foot down to overtake someone and my car just spluttered and refused to accelerate. It runs smooth on a steady throttle but as soon as I try and accelerate it just coughs and refuses to rev.

I managed to get to work and tried revving it in neutral, it won't go past 1500 rpm. If I hold it at below 1500 rpm it seems smooth. No smoke or noises and sounds ok at idle.

It is an 06 CLK320cdi (auto) with only 32k on the clock and has ran perfectly for the last 9 months in my ownership.

Any ideas? I am thinking possibly an EGR issue or a MAF issue but I don't really want to start guessing and throwing money at parts that might not need changing.

Thanks

Brian

[baptistsan]

Coil pack? But if no rough idle?

[trevalvole]

brian_H said:

Morning all

Any ideas? I am thinking possibly an EGR issue or a MAF issue but I don't really want to start guessing and throwing money at parts that might not need changing.

I'm no expert, but isn't there a thing where if you unplug the electrical connector for the MAF and the car runs better, i.e. on a default map that ignores the MAF, then it is probably the MAF? On the EGR, perhaps it has just got clogged up, so you could look into that without spending anything on parts.

[OldGermanHeaps]

These have an artificially low rev limit in neutral, so that can be discounted as a symptom.
Pretty sure its not a coil pack.
When was the last time the diesel filter was changed? If its only done 32k it might still be on its original.
Old mercs are very fussy about diag tools, its well worth paying a merc specialist indy to have it interrogated with star das.

Edited by OldGermanHeaps on Thursday 2nd April 11:20

[brian_H]

Thanks everyone.

I dropped it off at my local Merc Indy yesterday and he has rang to say it's fixed. Not a good phone connection so will post back when I have the diagnosis...and the bill!

Cheers

Brian

[Magic919]

baptistsan said:

Coil pack? But if no rough idle?

Diesels don’t have them.

[baptistsan]

Magic919 said:

Diesels don t have them.

Missed the diesel part of the op. Apologies.

[Mad Maximus]

A cheap code reader will help you understand faults and give you more info to either fix or at least have an idea. Cheap enough.

[OldGermanHeaps]

Generic obd readers work terribly with mercedes of that vintage, especially diesels. There is a high likelihood of going down the wrong path with a generic reader, it really needs to be something with manufacturers specific protocols.

[dreamcracker]

Turbo actuator is the most likely cause.