270 CDI W163 Constantly going into Limp mode and lititing to 2000ish rpm.

[Rоs]

Hi everyone!
Im new here and i have a few issues with my w163. Often the Merc decides it needs to go into limp mode and turns off the turbo and limits to 2000ish rpm. I have changed MAP sensor, air mass sensor, egr control valve, turbo control valve and it still cuts off the turbo evem after all of these changes. After i turn it off and back on the first 2 revs have turbo then after that it goes.
Please let me know if you have any ideas to why this would happen.
Thank you in advance
Ros

 

[mattkh]

Mileage..?
Manual OR Auto..?

 

[Mr Hatt]

I hate to say it but that sounds like a typical problem with the older OM642 prior to the improvement of the rubber seal on the turbo to intercooler pipe joint, there is a stepper motor that opens a secondary bank of inlet ports on the inlet manifold over 2000 revs and it has a tendency to die after being flooded by oil dripping on it over a period of time, once it does the car will go into limp every time you go over 2000 revs, its a reasonable size job to do yourself but not to difficult if your handy and have the right guidance

 

[Taffy7hfa]

Could be the swirl flap actuator.. could be a lot of things, guessing is pointless (and expensive) it needs diagnosis using star
I definitely wouldn't go replacing anything else without checking live data first.
Also its an OM612 not an OM642.

 

[Mr Hatt]

I stand corrected, which is a shame because M80 did a brilliant photolog of doing that job on a V6 cdi, as you have the earlier five cylinder I would still be looking at air volume as the issue and any reasonable diagnostic with live data will show that up for you, I use Foxwell and Launch but icarsoft will also give you that info regards steve

 

[Rоs]

We have diagnostics which is not star but has live data. What should i be looking for and what should the data be because right now im on my way to cornwall which is 300 miles away and for the past 150 miles i have been in limp mode wanting to smash my head in the dash

 

[Rоs]

Mileage..?
Manual OR Auto..?

140k auto

 

[oigle]

One can "bodge" the flaps quite easily and cheaply. Disconnect the flap linkage and lock the flaps in the open position. Then insert a suitable resistor (I think it is around 4.5K from memory) between the two electrical connectors that power the swirl flap motor and disconnect the leads from the swirl flap motor. Cost is virtually nothing. That would eliminate them from the possible faults happening.

 

[mattkh]

......insert a suitable resistor (I think it is around 4.5K from memory) between the two electrical connectors that power the swirl flap motor and disconnect the leads from the swirl flap motor.

Interesting.
So a very small current will go through these wires. Does this current trick the relevant module that the flap motor is working AND the flaps are fully open..???

 

[oigle]

It just tricks the ecu into thinking the motor is working properly. Otherwise, limp mode.

 

[Ivan Mihov]

Turbo vacuum boost valve or swirl flaps?

 

[oigle]

Just the swirl flaps.