Lou-in-NJ

The electronic actuator on my OM 642 turbo was clicking rapidly after I shut the vehicle off yesterday, I'll scan the. I looked under the hood and since I don't have the plastic beauty cover, I was able to see the actuator arm going back and forth. Before that incident, The engine felt like it was lacking boost. on this particular trip. Over the past 6 months, the boost would "pull off" occasionally on moderate acceleration, but never on hard acceleration, and I had been meaning to see if it was an exhaust waste-gate, or intake, diverter valve issue; I haven't studied the system enough to know if the turbo has both or only a waste-gate. My $100 code scanner shows a P0299.
Anyway, it looks like the electronic actuator can be replaced without replacing the entire turbo, but my question is, is this the most likely part that "went bad" or could there be another issue, like waste-gate arm adjustment or some such thing?
Here's a video of it after the engine was turned off and the car was essentially entirely shut down; the high pitched noise stops when the actuator stops clicking:
https://drive.google.com/file/d/1aoC...usp=drive_link

Quint22

Scene in other threads

1)Exhaust pressure sensor

2)The actuator wires that go to the turbo actuator can act as fusible link and need resoldering.

Those were two common themes for that code

Quint22

Wanted to add in my experience in other vehicles (not MB) the actuator electronics can go astray and they dont communicate with the ECU correctly and this causes problems. Also the actuator arm in the turbo that controls the veins can start sticking and this causes all kinds of problems. If its electrical just actuator usually, if its mechanical binding then turbo replacement.

Like I said this is on other variable vein turbos

Lou-in-NJ

Thanks for the replies folks. I'll post my findings when I get a chance to work on it. In the meantime I ordered a new actuator, and I'm not going to touch anything until I get it in, so if that's the issue, I'm only working on the problem once. I didn't realize that this is a variable-vane turbo, so I guess that eliminates the need for a waste-gate. As I said earlier, this is one area of the engine that I have not studied much yet...too many other projects and work going on at this point.

In the research I have done, it looks like the teeth on the actuator gear break off and the actuator "slips", this would explain the boost "pull-off" that was occurring over the last 6 months. And with broken teeth, the actuator probably can't put the turbo into it's "shut-down" position, which would explain the clicking after the engine is turned off. It certainly could be stuck vanes as well, and I'll explore that when I get into it.
Thanks again.

Quint22

Variable vane turbos can make alot of things less expensive and complex per say and add benefits such as no waste gate (maybe not a benefit), exhaust break which is actually a turbo break, and wider smoother range of operation. That being said variable vane turbos also have a actuator thats both electronic and mechanical that can fail, the gears for said operation, and the vanes themselves can start sticking.

Good luck and keep us updated.

Lou-in-NJ

I got the new actuator today and popped the E-clip off the actuator lever arm, and removed the linkage. I discovered a lot of play in the actuator lever arm, and compared it to the new actuator which had almost none. So without removing anything else, I used my flat profile 1/4" drive ratchet with a 10mm socket and removed 4 - 10x15 bolts from the actuator mounting plate; this turned out to be 1 more bolt than necessary as one of the bolts was for holding the mounting plate to the turbo. After that I wiggled the unit out of that area until I was able to get to the electrical connector, and then I used a small straight-blade screw driver and some thumb pressure on each side of the connector and wiggled the connector off the actuator. I assembled in reverse and was done in less than 15 minutes. I went for a test drive and while the check engine light may have gone off after several drive cycles, I didn't wait, and I cleared the code with my scanner. So unless I make a follow-up post, the new actuator fixed the issue, including the turbo "pull-off" I was getting regularly under moderate acceleration.
Someday I'll open the old actuator, but I'm going to say it probably has broken gear teeth as I suspected.
Here's the play I found in the old actuator:
https://drive.google.com/file/d/1bQy...ew?usp=sharing