Accelerator jams open!
#1
08-26-2008, 03:32 PM
Accelerator jams open!
I recently deposited my UK spec ’97 SLK with my local garage for a service and MOT (annual statutory test). The car passed but when I drove it home I was braking hard to turn into my road end when there was a rather loud ‘ping’ from underneath the car. This was accompanied by a pinging noise while driving it around town. A further inspection revealed that the rear discs need to be replaced. I supposethere may bea rusty bit on the discs which is catching although since then the problem is far less pronounced.
I can easily deal with this but since then the car has developed a more worrying problem. As you accelerate the throttle jams open, which is more than a little disconcerting! This only happens when the car gets to around 55mph and the pace of acceleration beyond this point is dictated by the pace beforehand. The car accelerates steadily and is accompanied by vibration through the steering wheel (the car has been sitting on the driveway some time – tyres perhaps?). When the car has accelerated as far as I dare allow it I slowly stop by braking hard – the pedal is fairly stiff to a point, whereupon it goes light and the problem frees itself. If you do not brake sufficiently hard or indeed take your foot off altogether the car will continue to accelerate, even when under the 55mph mark. Depending on how hard you brake this causes the warning lights for both ABS and ASR to come on. The curious thing is that when these lights are on the problem appears to be totally cured, and this is true if you start the car from cold with these on. When the lights go out the problem returns.
Incidentally I have noticed that my cruise control does not work but Ive never been in the habit of using this so I don’t know if this is related. Furthermore Ive noticed that the car is sometimes sluggish to accelerate and refuses to downshift, a problem cured by stopping and restarting the car. Even then the car seems very slow and always has done; I cant seem to get close to the factory acceleration figures!
Any advice gratefully received.
I can easily deal with this but since then the car has developed a more worrying problem. As you accelerate the throttle jams open, which is more than a little disconcerting! This only happens when the car gets to around 55mph and the pace of acceleration beyond this point is dictated by the pace beforehand. The car accelerates steadily and is accompanied by vibration through the steering wheel (the car has been sitting on the driveway some time – tyres perhaps?). When the car has accelerated as far as I dare allow it I slowly stop by braking hard – the pedal is fairly stiff to a point, whereupon it goes light and the problem frees itself. If you do not brake sufficiently hard or indeed take your foot off altogether the car will continue to accelerate, even when under the 55mph mark. Depending on how hard you brake this causes the warning lights for both ABS and ASR to come on. The curious thing is that when these lights are on the problem appears to be totally cured, and this is true if you start the car from cold with these on. When the lights go out the problem returns.
Incidentally I have noticed that my cruise control does not work but Ive never been in the habit of using this so I don’t know if this is related. Furthermore Ive noticed that the car is sometimes sluggish to accelerate and refuses to downshift, a problem cured by stopping and restarting the car. Even then the car seems very slow and always has done; I cant seem to get close to the factory acceleration figures!
Any advice gratefully received.
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dgrover
Mercedes SLK Class
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09-03-2008 08:47 AM
