Not sure what’s wrong c320
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 34
Likes: 1
2001 w203
Not sure what’s wrong c320
My 2001 c320 has recently been acting very weird but I don’t want to misdiagnose it. There are no engine codes that are popping up except one misfire but I cleared it and it hasn’t returned. The car feels like it’s incredibly underpowered , I could full throttle and it will take 10 seconds to reach redline. I originally thought it was one of the cats that was bad because when I put it up on the rack one sounds louder than the other .
Things I replaced alreasy
-maf
-precat 02 sensors
i have a video of both the cats and me driving it
video of me driving is me full throttle acceleration
https://www.dropbox.com/s/fbpo9jdq1b...%20AM.mov?dl=0
https://www.dropbox.com/s/n9elakgpzk...%20PM.mov?dl=0
Things I replaced alreasy
-maf
-precat 02 sensors
i have a video of both the cats and me driving it
video of me driving is me full throttle acceleration
https://www.dropbox.com/s/fbpo9jdq1b...%20AM.mov?dl=0
https://www.dropbox.com/s/n9elakgpzk...%20PM.mov?dl=0
Newbie
Joined: Nov 2018
Posts: 8
Likes: 0
C230 K
Do you have access to live data? It can take a while for codes to come up. But if you go under (check engine smooth running) under the data stream, you'll see an active misfire counter.. As you've already thrown a maf and two upstream o2s at it, I think some misdiagnosis is already done.. You need data to show what's happening. You can try pulling the front o2s again and test drive with them out. If the car has a lot of power, then you have plugged cat(s).
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 34
Likes: 1
2001 w203
Update : removed one side o2 sensor at a time and took for a drive, did not effect anything , after driving I put it on the rack and used my temp gun and got these measurements right below on the pipe where the o2 sensor goes
front o2 left side :415
rear o2 left side 335
front o2 right side 420
rear o2 left side 350
,
front o2 left side :415
rear o2 left side 335
front o2 right side 420
rear o2 left side 350
,
Newbie
Joined: Nov 2018
Posts: 8
Likes: 0
C230 K
How was the car acting before you needed to replace the MAF? Because the symptoms you are describing sound like a bad MAF. Iv'e had new MAFs fail within a week on several occasions. You may need to try another one.
Thread Starter
Junior Member
Joined: Dec 2013
Posts: 34
Likes: 1
2001 w203
If it was under a lot of load or you punched the throttle it would make everything misfire , replaces it over a year ago with an aftermarket one , failed again , just put an open one about 3 months ago in, and I’m not having those symptoms anymore
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Member
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From: Kansas
1999 SLK 5.5L 6-speed, 1993 300 SE
Check the vacuum lines to the vacuum actuator that controls your intake flaps (front of intake manifold). If it's stuck or not working you lose A LOT of top end power.
