When driving my 560SL down a gentle grade, it feels as though the car wants to subtly surge/brake repeatedly, when I have the accelerator pedal somewhere between accelerating and all the way off.
The garage here recently went through the linkage, cleaning and lubricating. The cruise also surges and backs on downslopes, and I even think I feel a little of that when it's on the level. But that's maybe a separate matter (maybe not). What puzzles me is the seeming "all on, all off" nature of the engine when on these downslopes.
Is it natural for the 560 to feel like it's in 2nd gear (meaning: a slight engine-braking when you take your foot off the gas?) when in normal driving mode?

Thanks in advance for your thoughts.

Tom

P.S....sold the MG!!


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Tom

'87 560 SL
'74 MGB

Sounds like you might have an out of adjustment throttle switch. During decel the actual degree that the engine brakes the car has a lot to do with wether it gets fuel or not. Above about 20-25mph the fuel is interupted by reverse current being applied to the EHA, whenever the throttle switch goes closed. If you had the ability to turn this off and on at will it would feel like the transmission shifting it is so distinct. During normal decl at 60 say, the first effect is slight and then the decel cut-off takes place and it is distintly noticable. It sounds to me that you are going in and out of this at subcruise throttle.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

Thanks Steve,
Is this something that I could do myself, or should I swing into the garage? I'm semi-handy, but know nothing about Mercedes-Benz cars. If it's not an expensive adjustment, I'd be delighted to have an expert make it right.
A follow-up: would this be the cause of my car surging/braking fairly dramatically when the cruise control is on (same problem, most noticeable on down-slopes)??

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Tom

'87 560 SL
'74 MGB

I'm especially curious about how this might affect the cruise control...most people talk about the amp...but I wonder if this would produce the same result.

Anyone have any thoughts?

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Tom

'87 560 SL
'74 MGB

Tom,
It's been 11 months. Did you get the throttle switch checked and re-adjusted? I am having the same trouble with my 560 which is subtle but I wonder if it will get worse.

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VR
1967 250SL