Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: lowpad on May 30, 2020, 18:30:06

Title: 230SL low-speed "bucking" on deceleration
Post by: lowpad on May 30, 2020, 18:30:06

My 230SL (and even my much newer 993) has always had a little bit of part throttle "bucking" on slow-speed deceleration.  A typical situation would be coming up to a stop sign at low speeds, in 1st or 2nd gear, wherein the car starts to buck, requiring either a full lift off of the accelerator or putting the car in neutral and just coasting.  This situation just got worse following a bunch of fuel system work to address a high idle and improve warm starting.  I've looked through past posts on this and related topics, but can't find any other similar situations.  I know that later cars had a fuel shutoff solenoid added to the FI pump, but the 230SL does not have this.  I can live with a bit of this, but the situation is now much worse than before.  Many thanks in advance for any suggestions.  Lowell

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: mistertj on June 06, 2020, 22:26:13

I occasionally got that but I was the cause...not able to keep my foot perfectly still. The gas pedal is very touchy, so I just lift my foot off of it when coming to a stop...and rest it on the brake.

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: lowpad on June 07, 2020, 17:41:52

Thanks.  That's my currently what I do, but I somehow doubted that the esteemed Mercedes development team would have accepted that as a solution!  I've noticed that my car doesn't have a throttle dashpot.  Going to see if that might help somewhat.

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: Melburnian on June 10, 2020, 07:42:40

An amateur here but have you checked the functioning of the dashpot? Mine was wrongly fitted with one to suit a 280slwhich is a different size  and wasnt engaging. Now I have replaced it the gear changes are much smoother requiring less skill  on the pedals.

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: lowpad on June 10, 2020, 23:56:55

Thanks.  I actually don’t have a dashpot and plan to install one. 

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: Melburnian on June 12, 2020, 01:11:55

yes sorry I just read your post again. Installing one will definitely improve the ease of driving. It prevents the revs dropping off quickly so gear changes are smoother. Whether it totally solves the issue? you never know your luck!

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: rumb on June 24, 2020, 17:23:43

Is your differential worn out? That will cause bucking when soft decelerating.

Title: Re: 230SL low-speed "bucking" on deceleration
Post by: Benz Dr. on June 24, 2020, 22:42:59

Check to see if your idle mixture is rich or lean at hot idle. Your engine could be hunting for fuel as it comes off of higher engine speeds.