Please help! Need "Dr. House" to diagnose this one.
09-28-2012, 10:01 AM
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c240 ml320 c280
Please help! Need "Dr. House" to diagnose this one.
I have a 1996 C280 with approximately 120k miles which I purchased for my son a couple of years ago. The car is great, and runs like a charm out on the highway, however there is a recurring problem with acceleration at low speeds. I have spent a lot of $$ trying to remedy this recurring problem.
In short the car is throwing a number of CEL codes, and conssistantly throws a camshaft sensor code. The cam shaft sensor has been replaced at least three times (by myself and by my local German car indy shop). The indy shop has also spent time with the vehicle and removed the valve cover, inspected the cam shaft clearance levels, and cam gear and tells me they are all within tolerances. At one point they replaced the throttle body actuator as well, but this problem has arose since.
The drivability issues are as follows: Car struggles to accelerate off the mark but only after it is hot. Hot humid weather seems to contribute to it, but the MAF sensor has been swapped out with no improvement. Seems the car runs borderline hot (110 to just below 120 degrees c on average). Auxiliary fans operate ok, I have replaced the aux fan relay and also the coolant temp sensor for good measure. Fans seem to cycle on and off ok. Running the A/C might be making the car run hotter and contribute to the drivability issue but I cannot be 100% sure. A/C has slow Freon leak. After car is hot and turned off, it always seems to have a very noticeable issue with the initial acceleration one restarted and placed in reverse or drive. The ignition at that point is being retarded or restrained by the CPU. When this happens, the gas pedal can be pressed all the way to the floor and the car will barely move. The car also seems to use an excessive amount of gas and sometimes smells “rich”. Once on the road, it struggles at lower speeds and the shifting from 1st to 2nd feels restrained and prolonged with very noticiable rough shifting in low gear.
Codes are as follows:
P1340 CMP Sensor
P0341 CMP Sensor circuit range problem (cam sensor replaced, cam magnet replace)
P0325 knock sensor
067 CMP signal implausible
081 maximum ignition retard on at least one cyl
Items replaced/troubleshot:
Replaced spark plugs, all sp wires, all coils
Replaced cam shaft sensor and camshaft balancer/magnet, physically checked tolerances and lifters, etc.
Sent out CPU for testing rebuild – came back tested good
Wiring harness in good shape
Replaced overload protection relay, aux fan relay, fuelpump relay
Replaced engine coolant temp sensor
Replace throttle body actuator
New battery (voltage a little low so replaced)
Replaced fuel filter
Tested different MAF
Bottom line, I can’t afford to throw parts at this any longer but I know it can be fixed if properly diagnosed.
Any insight into this or anyone with similar issues which they can share would be greatky appreciated!
I have a 1996 C280 with approximately 120k miles which I purchased for my son a couple of years ago. The car is great, and runs like a charm out on the highway, however there is a recurring problem with acceleration at low speeds. I have spent a lot of $$ trying to remedy this recurring problem.
In short the car is throwing a number of CEL codes, and conssistantly throws a camshaft sensor code. The cam shaft sensor has been replaced at least three times (by myself and by my local German car indy shop). The indy shop has also spent time with the vehicle and removed the valve cover, inspected the cam shaft clearance levels, and cam gear and tells me they are all within tolerances. At one point they replaced the throttle body actuator as well, but this problem has arose since.
The drivability issues are as follows: Car struggles to accelerate off the mark but only after it is hot. Hot humid weather seems to contribute to it, but the MAF sensor has been swapped out with no improvement. Seems the car runs borderline hot (110 to just below 120 degrees c on average). Auxiliary fans operate ok, I have replaced the aux fan relay and also the coolant temp sensor for good measure. Fans seem to cycle on and off ok. Running the A/C might be making the car run hotter and contribute to the drivability issue but I cannot be 100% sure. A/C has slow Freon leak. After car is hot and turned off, it always seems to have a very noticeable issue with the initial acceleration one restarted and placed in reverse or drive. The ignition at that point is being retarded or restrained by the CPU. When this happens, the gas pedal can be pressed all the way to the floor and the car will barely move. The car also seems to use an excessive amount of gas and sometimes smells “rich”. Once on the road, it struggles at lower speeds and the shifting from 1st to 2nd feels restrained and prolonged with very noticiable rough shifting in low gear.
Codes are as follows:
P1340 CMP Sensor
P0341 CMP Sensor circuit range problem (cam sensor replaced, cam magnet replace)
P0325 knock sensor
067 CMP signal implausible
081 maximum ignition retard on at least one cyl
Items replaced/troubleshot:
Replaced spark plugs, all sp wires, all coils
Replaced cam shaft sensor and camshaft balancer/magnet, physically checked tolerances and lifters, etc.
Sent out CPU for testing rebuild – came back tested good
Wiring harness in good shape
Replaced overload protection relay, aux fan relay, fuel pump relay
Replaced engine coolant temp sensor
Replace throttle body actuator
New battery (voltage a little low so replaced)
Replaced fuel filter
Tested different MAF
Bottom line, I can’t afford to throw parts at this any longer but I know it can be fixed if properly diagnosed.
Any insight into this or anyone with similar issues which they can share would be greatky appreciated!
In short the car is throwing a number of CEL codes, and conssistantly throws a camshaft sensor code. The cam shaft sensor has been replaced at least three times (by myself and by my local German car indy shop). The indy shop has also spent time with the vehicle and removed the valve cover, inspected the cam shaft clearance levels, and cam gear and tells me they are all within tolerances. At one point they replaced the throttle body actuator as well, but this problem has arose since.
The drivability issues are as follows: Car struggles to accelerate off the mark but only after it is hot. Hot humid weather seems to contribute to it, but the MAF sensor has been swapped out with no improvement. Seems the car runs borderline hot (110 to just below 120 degrees c on average). Auxiliary fans operate ok, I have replaced the aux fan relay and also the coolant temp sensor for good measure. Fans seem to cycle on and off ok. Running the A/C might be making the car run hotter and contribute to the drivability issue but I cannot be 100% sure. A/C has slow Freon leak. After car is hot and turned off, it always seems to have a very noticeable issue with the initial acceleration one restarted and placed in reverse or drive. The ignition at that point is being retarded or restrained by the CPU. When this happens, the gas pedal can be pressed all the way to the floor and the car will barely move. The car also seems to use an excessive amount of gas and sometimes smells “rich”. Once on the road, it struggles at lower speeds and the shifting from 1st to 2nd feels restrained and prolonged with very noticiable rough shifting in low gear.
Codes are as follows:
P1340 CMP Sensor
P0341 CMP Sensor circuit range problem (cam sensor replaced, cam magnet replace)
P0325 knock sensor
067 CMP signal implausible
081 maximum ignition retard on at least one cyl
Items replaced/troubleshot:
Replaced spark plugs, all sp wires, all coils
Replaced cam shaft sensor and camshaft balancer/magnet, physically checked tolerances and lifters, etc.
Sent out CPU for testing rebuild – came back tested good
Wiring harness in good shape
Replaced overload protection relay, aux fan relay, fuelpump relay
Replaced engine coolant temp sensor
Replace throttle body actuator
New battery (voltage a little low so replaced)
Replaced fuel filter
Tested different MAF
Bottom line, I can’t afford to throw parts at this any longer but I know it can be fixed if properly diagnosed.
Any insight into this or anyone with similar issues which they can share would be greatky appreciated!
I have a 1996 C280 with approximately 120k miles which I purchased for my son a couple of years ago. The car is great, and runs like a charm out on the highway, however there is a recurring problem with acceleration at low speeds. I have spent a lot of $$ trying to remedy this recurring problem. In short the car is throwing a number of CEL codes, and conssistantly throws a camshaft sensor code. The cam shaft sensor has been replaced at least three times (by myself and by my local German car indy shop). The indy shop has also spent time with the vehicle and removed the valve cover, inspected the cam shaft clearance levels, and cam gear and tells me they are all within tolerances. At one point they replaced the throttle body actuator as well, but this problem has arose since.
The drivability issues are as follows: Car struggles to accelerate off the mark but only after it is hot. Hot humid weather seems to contribute to it, but the MAF sensor has been swapped out with no improvement. Seems the car runs borderline hot (110 to just below 120 degrees c on average). Auxiliary fans operate ok, I have replaced the aux fan relay and also the coolant temp sensor for good measure. Fans seem to cycle on and off ok. Running the A/C might be making the car run hotter and contribute to the drivability issue but I cannot be 100% sure. A/C has slow Freon leak. After car is hot and turned off, it always seems to have a very noticeable issue with the initial acceleration one restarted and placed in reverse or drive. The ignition at that point is being retarded or restrained by the CPU. When this happens, the gas pedal can be pressed all the way to the floor and the car will barely move. The car also seems to use an excessive amount of gas and sometimes smells “rich”. Once on the road, it struggles at lower speeds and the shifting from 1st to 2nd feels restrained and prolonged with very noticiable rough shifting in low gear.
Codes are as follows:
P1340 CMP Sensor
P0341 CMP Sensor circuit range problem (cam sensor replaced, cam magnet replace)
P0325 knock sensor
067 CMP signal implausible
081 maximum ignition retard on at least one cyl
Items replaced/troubleshot:
Replaced spark plugs, all sp wires, all coils
Replaced cam shaft sensor and camshaft balancer/magnet, physically checked tolerances and lifters, etc.
Sent out CPU for testing rebuild – came back tested good
Wiring harness in good shape
Replaced overload protection relay, aux fan relay, fuel pump relay
Replaced engine coolant temp sensor
Replace throttle body actuator
New battery (voltage a little low so replaced)
Replaced fuel filter
Tested different MAF
Bottom line, I can’t afford to throw parts at this any longer but I know it can be fixed if properly diagnosed.
Any insight into this or anyone with similar issues which they can share would be greatky appreciated!
09-30-2012, 02:38 AM
#2
SPONSOR
Answer
I have a 1996 C280 with approximately 120k miles which I purchased for my son a couple of years ago. The car is great, and runs like a charm out on the highway, however there is a recurring problem with acceleration at low speeds. I have spent a lot of $$ trying to remedy this recurring problem.
In short the car is throwing a number of CEL codes, and consistently throws a camshaft sensor code. The cam shaft sensor has been replaced at least three times (by myself and by my local German car indy shop). The indy shop has also spent time with the vehicle and removed the valve cover, inspected the cam shaft clearance levels, and cam gear and tells me they are all within tolerances. At one point they replaced the throttle body actuator as well, but this problem has arose since.
The drivability issues are as follows: Car struggles to accelerate off the mark but only after it is hot. Hot humid weather seems to contribute to it, but the MAF sensor has been swapped out with no improvement. Seems the car runs borderline hot (110 to just below 120 degrees c on average). Auxiliary fans operate OK, I have replaced the aux fan relay and also the coolant temp sensor for good measure. Fans seem to cycle on and off ok. Running the A/C might be making the car run hotter and contribute to the drivability issue but I cannot be 100% sure. A/C has slow Freon leak. After car is hot and turned off, it always seems to have a very noticeable issue with the initial acceleration one restarted and placed in reverse or drive. The ignition at that point is being retarded or restrained by the CPU. When this happens, the gas pedal can be pressed all the way to the floor and the car will barely move. The car also seems to use an excessive amount of gas and sometimes smells “rich”. Once on the road, it struggles at lower speeds and the shifting from 1st to 2nd feels restrained and prolonged with very noticeable rough shifting in low gear.
Codes are as follows:
P1340 CMP Sensor
P0341 CMP Sensor circuit range problem (cam sensor replaced, cam magnet replace)
P0325 knock sensor
067 CMP signal implausible
081 maximum ignition retard on at least one cyl
Items replaced/troubleshot:
Replaced spark plugs, all sp wires, all coils
Replaced cam shaft sensor and camshaft balancer/magnet, physically checked tolerances and lifters, etc.
Sent out CPU for testing rebuild – came back tested good
Wiring harness in good shape
Replaced overload protection relay, aux fan relay, fuel pump relay
Replaced engine coolant temp sensor
Replace throttle body actuator
New battery (voltage a little low so replaced)
Replaced fuel filter
Tested different MAF
Bottom line, I can’t afford to throw parts at this any longer but I know it can be fixed if properly diagnosed.
Any insight into this or anyone with similar issues which they can share would be greatly appreciated!
In short the car is throwing a number of CEL codes, and consistently throws a camshaft sensor code. The cam shaft sensor has been replaced at least three times (by myself and by my local German car indy shop). The indy shop has also spent time with the vehicle and removed the valve cover, inspected the cam shaft clearance levels, and cam gear and tells me they are all within tolerances. At one point they replaced the throttle body actuator as well, but this problem has arose since.
The drivability issues are as follows: Car struggles to accelerate off the mark but only after it is hot. Hot humid weather seems to contribute to it, but the MAF sensor has been swapped out with no improvement. Seems the car runs borderline hot (110 to just below 120 degrees c on average). Auxiliary fans operate OK, I have replaced the aux fan relay and also the coolant temp sensor for good measure. Fans seem to cycle on and off ok. Running the A/C might be making the car run hotter and contribute to the drivability issue but I cannot be 100% sure. A/C has slow Freon leak. After car is hot and turned off, it always seems to have a very noticeable issue with the initial acceleration one restarted and placed in reverse or drive. The ignition at that point is being retarded or restrained by the CPU. When this happens, the gas pedal can be pressed all the way to the floor and the car will barely move. The car also seems to use an excessive amount of gas and sometimes smells “rich”. Once on the road, it struggles at lower speeds and the shifting from 1st to 2nd feels restrained and prolonged with very noticeable rough shifting in low gear.
Codes are as follows:
P1340 CMP Sensor
P0341 CMP Sensor circuit range problem (cam sensor replaced, cam magnet replace)
P0325 knock sensor
067 CMP signal implausible
081 maximum ignition retard on at least one cyl
Items replaced/troubleshot:
Replaced spark plugs, all sp wires, all coils
Replaced cam shaft sensor and camshaft balancer/magnet, physically checked tolerances and lifters, etc.
Sent out CPU for testing rebuild – came back tested good
Wiring harness in good shape
Replaced overload protection relay, aux fan relay, fuel pump relay
Replaced engine coolant temp sensor
Replace throttle body actuator
New battery (voltage a little low so replaced)
Replaced fuel filter
Tested different MAF
Bottom line, I can’t afford to throw parts at this any longer but I know it can be fixed if properly diagnosed.
Any insight into this or anyone with similar issues which they can share would be greatly appreciated!
My best advice is take it to the MB dealer for a diagnostic scan with the factory tool.
North America residents can subscribe to the Mercedes Benz Electronic Parts Catalog FREE...
http://epc.startekinfo.com/epc/subscribe.jsp
Here are some possible answers:
Has the camshaft ARMATURE been replaced, it has been superseded five times, the current part is MB# 110510043.
I suggest you remove and inspect the Flap resonance valve MB# 0001400431 for damage, if it is OK, re-install it.
There is a small air hose going from the upper to lower intake manifold, when it is damaged performance is horrible.
It sounds almost as if the catalytic converters or exhaust might be crushed/plugged.
Visual inspection + disconnect the exhaust from the manifold, run it to verify if some of the issues are suddenly gone.
I have dealt with the MB Wiring Harness Failure issue to many times.
Here is a link with extreme detailed data and pictures.
http://www.peachparts.com/shopforum/...s-failure.html
FYI:
* The engine control module has been superseded up to six times, depending on your VIN#.
* There are two fuel strainers in the tank, picture attached.
* The fuel rail pressure regulator has been superseded.
roy@pelicanparts.com
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