OM642 Loss of power/stumble at low acceleration
Thread Starter
Newbie
Joined: Sep 2023
Posts: 8
Likes: 1
2006 CLK 320 CDI AMG
OM642 Loss of power/stumble at low acceleration
Hello everyone,
An issue started appearing recently on my 2006 CLK 320 CDI (642.910 engine). When cold it drives like a dream, idles at 900rpm, good power, everything's fine.
However, for some reason, when it gets a bit warmer and the idle goes down to the normal 600rpm, the engine completely stumbles on low acceleration. And it isn't permanent, sometimes it disappears and I notice it when out of traffic, sometimes it stays there, sometimes it just doesn't appear at all. It happens when I slightly press the accelerator (let's say under ~40% pedal) and it just starts stumbling at 1100-1200 rpm until I reach about 1800 or so. If I accelerate above ~35-40% pedal it goes just fine, so traffic is a complete pain because the car shakes so heavily. Does the same thing in parking/neutral so I ruled out the gearbox - idle is fine, 1100+ rpm completely stumbles and RPM fluctuates like there's no power.
When at higher speeds it disappears, but it feels like I have no power around the 1100-1800RPM range. It accelerates very slowly until above that range. I saw some other threads about it being the EGR valve but I cleaned it, and it wasn't that dirty. Now I'm thinking either the EGR pipes going into the intake, or turbo seals + PCV valve to change. It just feels weird that the issue randomly appears and disappears.
Could it be as simple as the turbo seals, or is there something else wrong ? Dead EGR valve ? DAS shows no error codes and the EGR apparently works, as the open/close value fluctuates. Does anyone have the same problem and/or a fix ?
Thank you in advance
An issue started appearing recently on my 2006 CLK 320 CDI (642.910 engine). When cold it drives like a dream, idles at 900rpm, good power, everything's fine.
However, for some reason, when it gets a bit warmer and the idle goes down to the normal 600rpm, the engine completely stumbles on low acceleration. And it isn't permanent, sometimes it disappears and I notice it when out of traffic, sometimes it stays there, sometimes it just doesn't appear at all. It happens when I slightly press the accelerator (let's say under ~40% pedal) and it just starts stumbling at 1100-1200 rpm until I reach about 1800 or so. If I accelerate above ~35-40% pedal it goes just fine, so traffic is a complete pain because the car shakes so heavily. Does the same thing in parking/neutral so I ruled out the gearbox - idle is fine, 1100+ rpm completely stumbles and RPM fluctuates like there's no power.
When at higher speeds it disappears, but it feels like I have no power around the 1100-1800RPM range. It accelerates very slowly until above that range. I saw some other threads about it being the EGR valve but I cleaned it, and it wasn't that dirty. Now I'm thinking either the EGR pipes going into the intake, or turbo seals + PCV valve to change. It just feels weird that the issue randomly appears and disappears.
Could it be as simple as the turbo seals, or is there something else wrong ? Dead EGR valve ? DAS shows no error codes and the EGR apparently works, as the open/close value fluctuates. Does anyone have the same problem and/or a fix ?
Thank you in advance
Thread Starter
Newbie
Joined: Sep 2023
Posts: 8
Likes: 1
2006 CLK 320 CDI AMG
That's the thing, for some reason no engine codes are stored. Just one of my fog lights is dead so I have a front SAM code for it but that's it.
Even when I try erasing all codes in DAS (when I manage to catch the car in stumbling mode), nothing changes.
Even when I try erasing all codes in DAS (when I manage to catch the car in stumbling mode), nothing changes.
Thread Starter
Newbie
Joined: Sep 2023
Posts: 8
Likes: 1
2006 CLK 320 CDI AMG
Gauge on the dashboard rises normally, all my sensors are fine too. Just starts happening when the cold start RPMs decrease from 900 to 600rpm. That's why it sounds like EGR for me, but the valve is fully clean and I get no error codes.
Junior Member
Joined: Oct 2016
Posts: 15
Likes: 0
2011 R350 Bluetec
My 2011 R350 (350K KMs) has/had similar symptoms. I went thru this 120K ago and plan to do it again because its starting again.
1- Transmission fluid change (torque converter drain as well). Seems the the TC solenoid isn't locking in properly resulting in the shudder. I actually dropped the valve body and removed the solenoids to clean the screens, as well as separate the plate and cleaned the passages. I used varsol.
2- Replace the fuel filter. Critical item on diesels to be done, especially if you buy fuel from a bad tank.
This is the easy and inexpensive repair, if you diy.
1- Transmission fluid change (torque converter drain as well). Seems the the TC solenoid isn't locking in properly resulting in the shudder. I actually dropped the valve body and removed the solenoids to clean the screens, as well as separate the plate and cleaned the passages. I used varsol.
2- Replace the fuel filter. Critical item on diesels to be done, especially if you buy fuel from a bad tank.
This is the easy and inexpensive repair, if you diy.
Newbie
Joined: Dec 2024
Posts: 1
Likes: 0
Revive-OM642 Scr MB GLC 350d
[QUOTE=Lazarev8ch;8880347]Hello everyone,…
Hello all, I have a MB 2018 GLC350d with OM642 Scr engine. I have recently picked up this car with 111000km…and have exactly the issue explained in this thread. Have any of you managed to resolve the issue?
in sort, Icarsoft MB V3.0 identified left and right headlights low voltage. There are no issues or warning messages, no freeze frame info, all emissions ready however, poor acceleration from 0-1800rpm, and limited at 3500rpm. Obtained 7.2L/100km on a 300km round trip. I have replaced the fuel filter, oil, oil filter with MB dealer filter, replaced pcv cam shaft seal, inspected the turbo charge line through the intercooler, throttle body up to the intake manifold, inspected the egr and dpf for blockage. Turbo inlet had minimal oil induction from pcv before service.
I cannot see the swirl flaps, nor functioning. However, the vehicle sat at the dealer from June 2024 until end of November 2024. As per the service history print put, the previous owner neglected the Adblue religiously every 10000km, these errors are present on the dealer history readouts. I’ve discussed the above with a MB mechanic, he reccons without Xentry diagnostic that its a carbon issue, and a diesel additive would probably restore the engine…I am not convinced. Regards
Update 22/12/2024
Have and behold, the left raw air intake duct was torn and flexible. With low end torque, the engine requires maximum airflow. With the vacuum, the MAF sensor 1 showed 50% less air flow compared to MAF sensor 2. I’ve used a beer can as a temporary solution to provide the duct rigidity. Problem solved
Hello all, I have a MB 2018 GLC350d with OM642 Scr engine. I have recently picked up this car with 111000km…and have exactly the issue explained in this thread. Have any of you managed to resolve the issue?
in sort, Icarsoft MB V3.0 identified left and right headlights low voltage. There are no issues or warning messages, no freeze frame info, all emissions ready however, poor acceleration from 0-1800rpm, and limited at 3500rpm. Obtained 7.2L/100km on a 300km round trip. I have replaced the fuel filter, oil, oil filter with MB dealer filter, replaced pcv cam shaft seal, inspected the turbo charge line through the intercooler, throttle body up to the intake manifold, inspected the egr and dpf for blockage. Turbo inlet had minimal oil induction from pcv before service.
I cannot see the swirl flaps, nor functioning. However, the vehicle sat at the dealer from June 2024 until end of November 2024. As per the service history print put, the previous owner neglected the Adblue religiously every 10000km, these errors are present on the dealer history readouts. I’ve discussed the above with a MB mechanic, he reccons without Xentry diagnostic that its a carbon issue, and a diesel additive would probably restore the engine…I am not convinced. Regards
Update 22/12/2024
Have and behold, the left raw air intake duct was torn and flexible. With low end torque, the engine requires maximum airflow. With the vacuum, the MAF sensor 1 showed 50% less air flow compared to MAF sensor 2. I’ve used a beer can as a temporary solution to provide the duct rigidity. Problem solved
Last edited by Kragman3000; Dec 22, 2024 at 02:40 AM.
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MBWorld Fanatic!
Joined: Apr 2003
Posts: 1,032
Likes: 277
From: Northeast
2012 S350 Bluetec, 2014 GLK250 Bluetec, 2026 E350 4Matic
From what I read, I would start with fuel filter and go from there. They can provide any number of weird and random symptoms like this.
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