Heavy throttle on 202 C240

[stevesey]

The throttle on my C240 is bugging me a bit. It's the remote fly by wire type with the throttle sender unit located remotely in the engine compartment, in front of the passenger.

The throttle pedal has a return spring then the unit itself has 2 very chunky springs that are mounted in line with the spindle and are twisted as the throttle is pressed. Spings are part no 99 here - the top one is shown the other is below the lever (part 84).

My gripes are
a) too much pressure needed
b) springs bind - so fit you attempt to gently apply a liitle more throttle nothing happens until you apply enough extra force to overcome the binding friction - then the throttle moves a couple of mm suddendly. Have tried some lubrication - no help (don't want to go too wild and contaminate the sender unit itself.

I'm considering modifying this assembly - to either remove one spring, or to hook the springs onto a different part of the assemly so start with lower tension (this lloks easy on the top one as there is a suitable point about 90 degrees from the current attachment point. Obviously I need to ensure there is enough force to close the thtorrle in the event of a cable failure, so need to be cautious.

Anyone else tackled anything like this? Drove a pre-facelift direct cable car today and the throttle felt so much better - decided I have to do something.

 

[jberks]

Don't modify anything. Aside from anything else, get it wrong and the throttle sticks open (with the possibly disasterous results) and you're in seriously deep doo doo with the authorities.
It was ok, now it isn't - therefore what you need to do is get it back to factory spec rather than make modifications to compensate for the actual fault.
You mention the springs and the actuator but the fault you describe would normally be caused by a sticking cable. Have you checked/replaced the cable?

 

[stevesey]

I did say I'd need to be cautious!

Only had the car 4 weeks (so no idea what factory spec felt like - may have been the same). Fault is clearly with the sender/springs as I've disconnected it from the cable and turned by hand - feels just like it does using your foot/pedal, and you can see the springs binding against each other. Did check/grease cable/pedal as first move.

I think the next step will be to strip the unit (sufficiently) so I can inspect all of the springs and rub down/polish the touching surfaces of the coils (then lubricate lightly). Once it moves freely the tension might not feel like so much of an issue.

 

[jberks]

ah ok.
Well, MB throttles used to be heavy in the old days but since the introduction of the electronic pick up, they should be smooth and light. I've not heard anyone reconning the throttle switch. If you can, it would be heplful to take some photos as you go and post it in the DIY section. Could be useful to others having the same issue.
Before you start though, I'd ring the local MB parts desk and get a price on a new switch. I suspect it will be silly, but MB do have a habit of surprising you with sensibly priced spares from time to time so you never know your luck. AFter all, chances are that the fault is due to wear on the plastic components so maintenance may be tricky.
In any case, good luck with it and let us know how you go on.

 

[BlackC55]

I did say I'd need to be cautious!

Only had the car 4 weeks (so no idea what factory spec felt like - may have been the same). Fault is clearly with the sender/springs as I've disconnected it from the cable and turned by hand - feels just like it does using your foot/pedal, and you can see the springs binding against each other. Did check/grease cable/pedal as first move.

I think the next step will be to strip the unit (sufficiently) so I can inspect all of the springs and rub down/polish the touching surfaces of the coils (then lubricate lightly). Once it moves freely the tension might not feel like so much of an issue.

They do tend to be a bit heavy on the 202. Mine was for sure. Most people live with it. Some people do not even realise they are heavy.

 

[stevesey]

Just to report back - manged to lubricate the springs with some light grease, after allowing a couple of weeks for this to work its way around all the touching coils, this seems to have solved the stickiness. If I now gently apply a little more pressure to the throttle, it moves straight away, rather than waiting until you have applied enough force to overcome the initial friction.

Throttle is bugging me less as a result, I'll probably leave it at that as I'm slowly adapting to the feel/weight (although when I switch to the wife's Astra I'm consious of being a bit heavy footed - but it does have a lovely exhaust note)