Hello all,
I have a 1998 V6 SL320, which suddenly drops to firing on what feels like three cylinders only. Cutting the engine off, then restarting immediately, always cures the problem. The problem usually, but not always, occurs after a run of 200 km or more, but after the first occurrence, it gets more frequent.
I recently managed to reach a Mercedes garage while the engine was still running in this sad manner, and after about an hour of electronic analysis, the garage changed coils N°s 3 and 5. (plus attendant plug leads )
I thought the possibility of two coils breaking down and then curing themselves simmultaneously was unlikely, but agreed to change them for want of another solution.
After 240 km, the problem occurred again, so I stopped the car for the night. The next day it occurred once after 200 km, then again 40 km later.
Oil & water temperatures are perfectly normal & everything else works fine on the car. The next-to-last occurrence happened after I had been stuck for nearly three minutes at roadworks traffic lights, so I thought it might be under-bonnet heat build-up, but 40 km later it happened after a 6-kilometer downhill run, foot almost completely off the accelerator !
Clearly I can't drive 200 kilometers every day just to provoke the incident, and the garages can't analyse the incident data on the inboard electronics because this model does not retain memory of incidents.
Does anybody have any idea which component or phenomenon could cause coils 3 & 5 to shut down in this manner ?
Any help or advice appreciated
Many thanks
Langlois
I have a 1998 V6 SL320, which suddenly drops to firing on what feels like three cylinders only. Cutting the engine off, then restarting immediately, always cures the problem. The problem usually, but not always, occurs after a run of 200 km or more, but after the first occurrence, it gets more frequent.
I recently managed to reach a Mercedes garage while the engine was still running in this sad manner, and after about an hour of electronic analysis, the garage changed coils N°s 3 and 5. (plus attendant plug leads )
I thought the possibility of two coils breaking down and then curing themselves simmultaneously was unlikely, but agreed to change them for want of another solution.
After 240 km, the problem occurred again, so I stopped the car for the night. The next day it occurred once after 200 km, then again 40 km later.
Oil & water temperatures are perfectly normal & everything else works fine on the car. The next-to-last occurrence happened after I had been stuck for nearly three minutes at roadworks traffic lights, so I thought it might be under-bonnet heat build-up, but 40 km later it happened after a 6-kilometer downhill run, foot almost completely off the accelerator !
Clearly I can't drive 200 kilometers every day just to provoke the incident, and the garages can't analyse the incident data on the inboard electronics because this model does not retain memory of incidents.
Does anybody have any idea which component or phenomenon could cause coils 3 & 5 to shut down in this manner ?
Any help or advice appreciated
Many thanks
Langlois