hard time accelerating
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 35
Likes: 3
2007 r320
hard time accelerating
So I will give a brief history, may or may not be related to the current problem but I will reference it just in case.
Last fall, the car ( 2007 R320 CDI) wouldnt start or would barely start in weather near or below 0c (32F). So the car sat all winter long not being driven. I have since changed a shorted alternator and a glow plug module and the car has been driving fine all summer long without issue. However it is now early fall again, and weather is reaching near 0c and the car starts fine, but has a hard time accelerating. It doesnt seem to matter if I let the car warm up for a half hour, or jump in it and go. No matter how i press the pedal, the car doesnt want to get out of its own way.
I was told maybe coolant temp sensor issue, making he vehicle run lean, but on my dash display, it shows accurate temperatures. I do have a MAF sensor code, could a bad MAF in cold weather, cause the car to run lean and fall on its face while accelerating?
Hopefully someone has some input or has had a similar experience.
Thanks in advance!
Last fall, the car ( 2007 R320 CDI) wouldnt start or would barely start in weather near or below 0c (32F). So the car sat all winter long not being driven. I have since changed a shorted alternator and a glow plug module and the car has been driving fine all summer long without issue. However it is now early fall again, and weather is reaching near 0c and the car starts fine, but has a hard time accelerating. It doesnt seem to matter if I let the car warm up for a half hour, or jump in it and go. No matter how i press the pedal, the car doesnt want to get out of its own way.
I was told maybe coolant temp sensor issue, making he vehicle run lean, but on my dash display, it shows accurate temperatures. I do have a MAF sensor code, could a bad MAF in cold weather, cause the car to run lean and fall on its face while accelerating?
Hopefully someone has some input or has had a similar experience.
Thanks in advance!
Newbie
Joined: Nov 2018
Posts: 12
Likes: 2
2007 Mercedes R320
I have the same car and i have had problems with the car going into limp mode because of high backpressure in the exaust system.
1. You can try pulling out the EGR valve to see if it is clogged, if it is, just clean it and see if the problem goes away.
2. If the EGR is not clogged get the stealer to check the exhaust flow to uncover any issues with backpressure. If you have issues with backpressure it might bee problems with the DPF, clogged or severely restricted flow and a forced regeneration might be what it needs.
3. Try cleaning the MAF sensor or buy a used one, instal it and delete the codes to see if the problem goes away.
1. You can try pulling out the EGR valve to see if it is clogged, if it is, just clean it and see if the problem goes away.
2. If the EGR is not clogged get the stealer to check the exhaust flow to uncover any issues with backpressure. If you have issues with backpressure it might bee problems with the DPF, clogged or severely restricted flow and a forced regeneration might be what it needs.
3. Try cleaning the MAF sensor or buy a used one, instal it and delete the codes to see if the problem goes away.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 35
Likes: 3
2007 r320
I have the same car and i have had problems with the car going into limp mode because of high backpressure in the exaust system.
1. You can try pulling out the EGR valve to see if it is clogged, if it is, just clean it and see if the problem goes away.
2. If the EGR is not clogged get the stealer to check the exhaust flow to uncover any issues with backpressure. If you have issues with backpressure it might bee problems with the DPF, clogged or severely restricted flow and a forced regeneration might be what it needs.
3. Try cleaning the MAF sensor or buy a used one, instal it and delete the codes to see if the problem goes away.
1. You can try pulling out the EGR valve to see if it is clogged, if it is, just clean it and see if the problem goes away.
2. If the EGR is not clogged get the stealer to check the exhaust flow to uncover any issues with backpressure. If you have issues with backpressure it might bee problems with the DPF, clogged or severely restricted flow and a forced regeneration might be what it needs.
3. Try cleaning the MAF sensor or buy a used one, instal it and delete the codes to see if the problem goes away.
thank you for the reply, I will look into this
Newbie
Joined: Nov 2018
Posts: 12
Likes: 2
2007 Mercedes R320
No problem. If you pull out the EGR make sure you get a new seal from the dealer so you can replace it before putting the EGR back. Note that there are only 2 screws on the EGR and that it can be hard to get it off once the screws are out. Spray some penetrating stuff to make the job of twisting it off a bit easier. Also, problems with the DPF can throw codes for the EGR.
Please come back with the solution when you get it solved.
Please come back with the solution when you get it solved.
