Akroyd-Stuart
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- Jul 30, 2008
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New member, first post - with problems...
I've owned a Mercedes 207D van from new (1981) - purchased from a long gone Mercedes commercial dealer in Birmingham (Colmore Depot). It was fitted out as a camper van in 1985 and used seasonally since then - averaging 2000 miles per annum. All told, it’s so far done 52,000 miles - not exactly stretched to the same extent as your average commercial beast of burden, and has never been thrashed or abused.
Anyhow, the problem now lies with an intermittent juddering, pulsing, jerking sensation, when the engine is put under load when accelerating up through each gear, particularly in second, and worst of all in third gear, on a more or less level road. The juddering is related to the lower engine revs that occur after engaging a progressively higher gear. As engine revs build up to the higher end of the range for each gear ratio so the juddering stage fades away. The vehicle has been driven 300 miles in this condition and shows no change in mpg and pulls well up hills at the most favourable engine revs.
This new tendency to develop juddery motion in 1st 2nd and 3rd gear seems to be related to a trait the vehicle has always had, and therefore may not be an entirely new phenomenon but a sudden worsening of an existing fault. This odd trait first presented itself years ago, when the vehicle was still in near new condition and was taken to the Lake District. Once bottom gear was engaged for the purpose of climbing its first very steep hill, I first discovered what for me has always been an odd but bearable ‘characteristic’.
Keeping the accelerator in a constant position, on very steep hills the vehicle quickly assumes a jerky progression up the gradient. With each jerk the severity gets worse until after 8 or so increases in severity driver intervention becomes a dire necessity. Easing off the gas, slowing down and then accelerating back up to original climbing speed does the trick, but only for a short while. Instead of being able to chug up a steep hill at a steady pace in bottom gear I have always had to adopt a fast-slow-fast-slow technique. Once into 2nd gear the vehicle would return to normal running and behave in a conventional way.
For years, I wrote this behaviour off as ‘the nature of the beast’, and was able to cope with it OK, insofar as it was predictable, and hills were avoidable. However, it is this same pulsing sensation that suddenly seems to be developing throughout all the gears, even when the engine is under light/moderate load, on a level road.
I’ve taken the vehicle to my local commercial vehicle specialist for an MOT and a general investigation. There first suspicion was the injector pump diaphragm - which was OK. Injectors serviced. Compression good. All filters replaced. Changed everything that needs changing. The injector pump was sent to a specialist company in Birmingham for performance bench testing, where they found nothing fundamentally wrong. Put it all back together, and it’s still juddering. Complete mystery.
The local expert reckons the vehicle is perfectly drivable in its current condition - it won’t break down or anything - but this constant juddering under acceleration is what you might expect from a Trabant two stoke - not a Mercedes 616 engine!
It’s main diet is usually courtesy of Messrs Tesco and Sainsbury. I had heard recent rumours of some dirty supermarket petrol playing up the electrickery of modern engines. However this old dowager drinks derv, and is pre-EMS or anything like that - its tastes are simple...
If anyone out there recognises any of these completely odd symptoms and can shed light on what my next course of action might be, their advice will be much appreciated.
I've owned a Mercedes 207D van from new (1981) - purchased from a long gone Mercedes commercial dealer in Birmingham (Colmore Depot). It was fitted out as a camper van in 1985 and used seasonally since then - averaging 2000 miles per annum. All told, it’s so far done 52,000 miles - not exactly stretched to the same extent as your average commercial beast of burden, and has never been thrashed or abused.
Anyhow, the problem now lies with an intermittent juddering, pulsing, jerking sensation, when the engine is put under load when accelerating up through each gear, particularly in second, and worst of all in third gear, on a more or less level road. The juddering is related to the lower engine revs that occur after engaging a progressively higher gear. As engine revs build up to the higher end of the range for each gear ratio so the juddering stage fades away. The vehicle has been driven 300 miles in this condition and shows no change in mpg and pulls well up hills at the most favourable engine revs.
This new tendency to develop juddery motion in 1st 2nd and 3rd gear seems to be related to a trait the vehicle has always had, and therefore may not be an entirely new phenomenon but a sudden worsening of an existing fault. This odd trait first presented itself years ago, when the vehicle was still in near new condition and was taken to the Lake District. Once bottom gear was engaged for the purpose of climbing its first very steep hill, I first discovered what for me has always been an odd but bearable ‘characteristic’.
Keeping the accelerator in a constant position, on very steep hills the vehicle quickly assumes a jerky progression up the gradient. With each jerk the severity gets worse until after 8 or so increases in severity driver intervention becomes a dire necessity. Easing off the gas, slowing down and then accelerating back up to original climbing speed does the trick, but only for a short while. Instead of being able to chug up a steep hill at a steady pace in bottom gear I have always had to adopt a fast-slow-fast-slow technique. Once into 2nd gear the vehicle would return to normal running and behave in a conventional way.
For years, I wrote this behaviour off as ‘the nature of the beast’, and was able to cope with it OK, insofar as it was predictable, and hills were avoidable. However, it is this same pulsing sensation that suddenly seems to be developing throughout all the gears, even when the engine is under light/moderate load, on a level road.
I’ve taken the vehicle to my local commercial vehicle specialist for an MOT and a general investigation. There first suspicion was the injector pump diaphragm - which was OK. Injectors serviced. Compression good. All filters replaced. Changed everything that needs changing. The injector pump was sent to a specialist company in Birmingham for performance bench testing, where they found nothing fundamentally wrong. Put it all back together, and it’s still juddering. Complete mystery.
The local expert reckons the vehicle is perfectly drivable in its current condition - it won’t break down or anything - but this constant juddering under acceleration is what you might expect from a Trabant two stoke - not a Mercedes 616 engine!
It’s main diet is usually courtesy of Messrs Tesco and Sainsbury. I had heard recent rumours of some dirty supermarket petrol playing up the electrickery of modern engines. However this old dowager drinks derv, and is pre-EMS or anything like that - its tastes are simple...
If anyone out there recognises any of these completely odd symptoms and can shed light on what my next course of action might be, their advice will be much appreciated.
