R129 Jerky Acceleration/Rough idle

skolt1

New Member
Joined
Apr 10, 2017
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3
Car
R129 SL500
Hello,

I've just bought my first SL, and it's fantastic!


I've a 1994 R129 SL500, it drives smooth as silk under normal driving conditions...

However, under heavy acceleration the engine jerks quite severely. When the car is idling it's fairly erratic and occasionally cuts out.

From my limited knowledge, I would guess that the Air Mass meter could be a possible cause.

My question is; are these units easily serviced? And if not could anyone recommend a good replacement?

Thanks in advance
 

Pontoneer

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Aug 19, 2002
Messages
15,663
Location
Central Scotland
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'99 S320 W140
While I can't answer your question , I'd suggest that as a good starting point ensure that all the basics are right - that the car has been serviced with clean filters , good distributor caps/plugs , all of which can affect the running , check for vacuum leaks under the bonnet as these can affect idling in particular .

Chances are it will be something fairly minor . If it hasn't been already done , a service by a decent Indy who knows his way round the cars would be the first thing to do , IMHO . If it does turn out there's something wrong , the Indy would be the best person to advise you .

If you let us know which part of the country you are in , someone will recommend a decent place to take it .
 

RichardF

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Joined
Aug 24, 2013
Messages
561
Car
Sl 320
Read the codes before you chuck any money at it. A blink code reader is all you should need on a 94.
 
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skolt1

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Joined
Apr 10, 2017
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3
Car
R129 SL500
Thank for the info. I'm up in Northern Scotland, so Aberdeen/Inverness are the closest places to me.

The car was serviced by Gem-Tech in Romford Essex. It had the works done just a few hundred miles ago (filters plugs gearbox etc.) I've only heard good things about the guys down there, and sure that this problem is a new one.

I'll certainly invest in a code reader prior to chucking money at the problem.

Thanks
 

Pontoneer

MB Club Veteran
Joined
Aug 19, 2002
Messages
15,663
Location
Central Scotland
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'99 S320 W140
Sorry I can't recommend anyone nearer .

However I can recommend Merparts in Port Glasgow , who are about as close as you will likely find a top notch specialist . I'm in North Ayrshire and they are the only guys I'd trust implicitly to work on my cars . Both Paul and Stef there are Mercedes-Benz master technicians and they work on lots of R129s ( they also have one breaking just now ) .

Their details in the link

Merparts Ltd Independent Mercedes Benz Specialist
 

Pontoneer

MB Club Veteran
Joined
Aug 19, 2002
Messages
15,663
Location
Central Scotland
Car
'99 S320 W140
Oh , I do have an acquaintance who lives up in Fortrose and who breaks Mercs , not sure of his current stock though .
 
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skolt1

New Member
Joined
Apr 10, 2017
Messages
3
Car
R129 SL500
Pontoneer, Thanks.
Ill give them a shout.

I've had the MAF out, cleaned it thoroughly with CRC contact cleaner - and all seems to be good!
 

d w124

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Dec 30, 2008
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12,380
Location
london
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w124 3.6AMG styling E320 S124 Lorinser styling
Still on original wiring loom??
 

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