JG26_Irish
10-21-2005, 07:18 AM
Greetings,
I have a 1997 MB C36 AMG. USA car. Awesome car! unbelieveable bottom end for a little straight six. Recently, got a yellow check engine light and a slight loss of bottom end engine performance at partial throttle (1-25%). Called dealer and took car in that day for analysis. ECU codes said that oxygen (OE) sensor was at fault. Dealer reset codes and we decided to drive it a few days and see if we had a repeat.
About three days later, the same code repeated and was again reset at MB dealer and two new Bosch OE sensors ordered. On the way home, I remembered the advice of my Porsche mechanic to periodically run a bottle of techron thru the car to keep oxygen sensor clean and injectors working right. Before, that the engine performance was mostly normal but occasionally repeated the loss of lowend response. Ran a bottle of Techron thru one tank of gas over about a 1-week period with liberal full throttle use whenever possible. After about 2-3 days full engine performance was restored and car ran normal for the next three weeks. Smoked one new Mustang on top end and got smoked by one bad V8 SS Camero with substantial engine mods (yeah, I know dumb to pick on a tiger , lol). Overall, I was pleased with how the car was running.
Dealer called to let me know the sensors were in and we had then installed two days ago. Car was normal going in. When returned to me the lowend throttle response was poor, just as it had been when the first code was experienced??? What's up with that? We went back to the dealer who rechecked and verified that the codes had been cleared and the the sensors calibrated and that all was installed correctly, the part numbers were right, etc. I still have the old sensors. Car was test driven and still seems sluggish at partial throttle (<25%) and instead of accellerating smartly, it pulls weakly and eventually downshifts to accellerate (less than normal). Needless to say, I am not pleased at the moment.
MB Dealer is checking with his technical rep and asking them to check with AMG for trouble shooting advice. I am checking with the rest of the world. Questions:
1.) Is it possible for a new OE sensor to harm engine performance?
2.) Does a Bosch OE Sensor (these appear to be two different heated type units) require a few heat cycles to perform correctly?
3.) What should we be looking for to trouble shoot the loss of engine performance? I have not driven it long enough to check fuel mileage.
4.) Full throttle peformance seem more or less normal. Still that is harder to judge since it is hard to find clear places to really turn it loose and even when I do, there are not good references to judge by. If I had the Mustang owner handy that might help
5.) Have others had this problem? or what sort of symptoms appeared when OE sensors failed?
My symptoms again, sluggish engine response to initial throttle from 1-25%. Cruising at moderate pace of about 40-45mph, in 5th gear, normal response to parial throttle was a very responsive, very torquey rapid accelleration usually without downshift unless throttle was applied very rapidly. Now I get a weaker response, less accelleration and more often than not a downshift to 4th or even 3rd gear as the engine fails to accellerate and the ECU tries to compensate with a downshift. That is not normal and only reappeared after OE sensor replacement.
Help?
Irish
I have a 1997 MB C36 AMG. USA car. Awesome car! unbelieveable bottom end for a little straight six. Recently, got a yellow check engine light and a slight loss of bottom end engine performance at partial throttle (1-25%). Called dealer and took car in that day for analysis. ECU codes said that oxygen (OE) sensor was at fault. Dealer reset codes and we decided to drive it a few days and see if we had a repeat.
About three days later, the same code repeated and was again reset at MB dealer and two new Bosch OE sensors ordered. On the way home, I remembered the advice of my Porsche mechanic to periodically run a bottle of techron thru the car to keep oxygen sensor clean and injectors working right. Before, that the engine performance was mostly normal but occasionally repeated the loss of lowend response. Ran a bottle of Techron thru one tank of gas over about a 1-week period with liberal full throttle use whenever possible. After about 2-3 days full engine performance was restored and car ran normal for the next three weeks. Smoked one new Mustang on top end and got smoked by one bad V8 SS Camero with substantial engine mods (yeah, I know dumb to pick on a tiger , lol). Overall, I was pleased with how the car was running.
Dealer called to let me know the sensors were in and we had then installed two days ago. Car was normal going in. When returned to me the lowend throttle response was poor, just as it had been when the first code was experienced??? What's up with that? We went back to the dealer who rechecked and verified that the codes had been cleared and the the sensors calibrated and that all was installed correctly, the part numbers were right, etc. I still have the old sensors. Car was test driven and still seems sluggish at partial throttle (<25%) and instead of accellerating smartly, it pulls weakly and eventually downshifts to accellerate (less than normal). Needless to say, I am not pleased at the moment.
MB Dealer is checking with his technical rep and asking them to check with AMG for trouble shooting advice. I am checking with the rest of the world. Questions:
1.) Is it possible for a new OE sensor to harm engine performance?
2.) Does a Bosch OE Sensor (these appear to be two different heated type units) require a few heat cycles to perform correctly?
3.) What should we be looking for to trouble shoot the loss of engine performance? I have not driven it long enough to check fuel mileage.
4.) Full throttle peformance seem more or less normal. Still that is harder to judge since it is hard to find clear places to really turn it loose and even when I do, there are not good references to judge by. If I had the Mustang owner handy that might help
5.) Have others had this problem? or what sort of symptoms appeared when OE sensors failed?
My symptoms again, sluggish engine response to initial throttle from 1-25%. Cruising at moderate pace of about 40-45mph, in 5th gear, normal response to parial throttle was a very responsive, very torquey rapid accelleration usually without downshift unless throttle was applied very rapidly. Now I get a weaker response, less accelleration and more often than not a downshift to 4th or even 3rd gear as the engine fails to accellerate and the ECU tries to compensate with a downshift. That is not normal and only reappeared after OE sensor replacement.
Help?
Irish