ML270CDI Limp Mode Without Rev Limit Possible?

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Thirstymerc

New Member
Joined
May 24, 2015
Messages
4
Car
06 ML500, 01 ML270CDI
Hi Guys,

I've just been through the whole choked inlet manifold saga with my ML270. At the EGR was putting into limp mode with a 3000 rev cap. I've removed the swirl flaps and cleaned the EGR. Since putting it all back together it ran fine for a couple of weeks. I put the remaining pipe on yesterday between the air box and the plastic box in the corner of the engine bay which I assume to be some kind of cold air draw. Now it has no power again but without the rev limit. I suspected I'd somehow hit something that had disabled the variable turbo boost so I checked it on Star Diag. The only code was yet another EGR code. If that were the case is it possible this is a different kind of limp mode which disables boost but doesn't limit revs? I know that the turbo actuator is controlled my vacuum as is the EGR. Is it possible that I've done something to the vacuum system that has disabled both the egr and the turbo but is only showing an EGR code. Where is the vacuum generated? I pulled the hoses at the EGR and turbo solenoids and there is a slight vacuum at each when idling. Any pointers would be greatly appreciated.

Cheers,

John
 
If you have been working down in the off side front region ( connecting the cold inlet) you may have disturbed the vacuum. There is a spherical Component ( about 3 inches diameter) mounted to the offside wing behind the drivers light with that looks like a clear fuel filter and 2 or 3 pipes, check those haven't been disturbed. If you disconnect one of those you get your symptom, I.e no turbo, no kick down response, very slow acceleration and rev limits between 2 and 3000 rpm but with no visible indicators for limp mode, also it doesn't clear and behave properly after an ignition off, retry, which usually clears a limp fault for a while.
I guess check all vacuum pipes around that area and down near the turbo as it soundalike that to me.
My pipe was disturbed at the mot when the drivers side headlight bulb was changed, and the mechanic must have disconnected the pipe for easier access and forgot to re connect it.
Hope it's something as simple as this for you.
Good luck.
MOZ
 
Thanks MOZ, you hit it in one! I've spent too much time looking at complex issues lately and made the mistake of not looking for the simple fix. The little clear line from the solenoid to the joiner had separated. No idea why it threw an EGR code and not a low boost one.

Cheers,

John
 

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