W211 E320 CDI - Occasional limp mode & pulsing power delivery

[Rawhide]

Hi, I have a 2004 E320 CDI Estate. (OM648 engine). I gave it a gearbox and oil service about 4k ago and it's been running pretty well. I also fixed injector blow by on cylinder 1 which seems to be fine still.

Recently it seems when it's just started up and generally warming up when at partial throttle seems like it's gently pulsing. It's barely noticeable but you can see it on the tach as well.

Sometimes I have to give it some gas when it's warming up as I need to exit a side road quickly due to traffic and I've noticed a limp mode seems to be triggered. The car has almost no power and doesn't want to rev much past 1k rpm. When I pull over and put in neutral it won't rev past 3k. This is I assume the 'limp mode' but there is nothing on the dash. It does not seem to happen when the car is warm. When I restart the car it's fine again.

The car also feels a bit down on power but that might just be in my head. My wife has the same exact car but it's remapped so it feels a lot more urgent as I think it has a more agressive map for the lower end.

MPG is spot on and no other issues.

I ran a scan on the engine and the only stored code I am getting is 2632-000 'Charge pressure control'.

On my to-do list is to change the diesel filter. I think the car is making the correct level of boost when I last checked using the torque app.

Any ideas welcome.

 

[350cls]

Do you drive the car in C mode or S mode. Does the car behave the same in both modes?
I have the same exact car/engine. I find when cold the car hunts for revs slightly on the first few hundred yards but after this it runs fine. I also found |S mode suits the car much more. My car has covered over 205,000.00 miles. I have never had or felt the car go into limp mode. Its also not good to rev the car over 3,000. revs until fully warm or up to temp.

 

[Larkone]

Remove and clean out the turbo actuator of all of the back dust that will have accumulated. I would also lube the gear wheels with some hi-temp grease. Check that none of the connections have started to break down. Clear the code and see if it comes back.

 

[Rawhide]

Do you drive the car in C mode or S mode. Does the car behave the same in both modes?
I have the same exact car/engine. I find when cold the car hunts for revs slightly on the first few hundred yards but after this it runs fine. I also found |S mode suits the car much more. My car has covered over 205,000.00 miles. I have never had or felt the car go into limp mode. Its also not good to rev the car over 3,000. revs until fully warm or up to temp.

Thanks - I too drive it in S mode in general. It makes no real difference to the performance but I think it might kick down a bit sooner. To be clear I don't drive the car hard when warming up. I only revved to 3k to see if it was limited. Where I live there is very little traffic but sometimes I need to join fast roads quite quickly before the car has fully warmed up. Not ideal but it can cause this issue.

Remove and clean out the turbo actuator of all of the back dust that will have accumulated. I would also lube the gear wheels with some hi-temp grease. Check that none of the connections have started to break down. Clear the code and see if it comes back.

Thanks - good advice. I'll search for this component and give this a go.

 

[Larkone]

Its the box with the black cover bolted to the turbo



You can get them re-furbed for under£100

 

[toolman1954]

Whilst you have your head under the bonnet and your hands dirty, try cleaning out your EGR Valve.
See my post here i made recently....EGR Valve Cleaning. 2003 E320 CDi.
Having now driven the car for a bit after the clean out of the valve, I can report that the engine feels much more tractable and just pulls much more smoother.

Steve.

 

[steve.thomson92]

I know the post is a few years old but would like to point out to larkone and anybody in the future, the turbo actuator on the 648 engine is an absolute nightmare to get at unlike the other derv engines they put in the c/e/s class where the turbo is on the top at the back and so much easier to get to hope this helps