W124 idling problem

tim124

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Your Mercedes
W124 E280 Estate/1995/2.8
Vehicle is a W124 220E estate, auto, '93 K-reg, 208K miles. Problem seems to occur when the engine is warm: on slowing down and moving without use of the accelerator pedal (eg when edging forward in traffic) the engine sometimes revs up and down (as if it's hunting for the correct idle speed) and this causes the car to 'stutter' as it moves. This happens in forward (D) and reverse. Any suggestions as to what this might be? Thanks.
 

47p2

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Slk
Maybe the stepper motor throttle body requiring a clean
 

The Crooner

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2006 R320 cdi
A search of the forums using the words poor idle will bring up loads of posts, a few from me, about your issue.

There is no one answer, but first thing to say ids that if it occurs when hot then a the temperature sensor might be at fault.

They are cheap enough to buy from MB, and worth a try.

If that doesn't cure it you have some reading and diagnosing to do.

All the info you need is here.

Tony
 

jibcl500

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CL500,ML55,SLK280
On a 220 check the condition of the engine wiring loom they break up and start to cause running issues.
One test with the engine running is massage the loom from the MAF if the engine starts to stutter or stall then the loom needs replacing.
I had the same issues and managed to rewire all areas affected but it can cause damage if not sorted.

jib
 

television

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2002 SL500, 216 CL500, all fully loaded
With the idle,,if the revs go up and down above that of the normal idle speed, then a vacuum pipe could be off or leaking

If the idle is falling up and down below the normal idling, then a mixture or other fault
 

jibcl500

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I'd put £100 on the engine loom seen it too many times before, if the MAF loom is faulty and shorting it will damage the MAF.


jib
 

grober

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W204 C200cdi estate
First clean the throttle body throat (where the flap is) with carburettor cleaner or a similar solvent. Remove the top of the air cleaner box( held on with clips--disconnect the maff circular connector (turn anti clockwise) remove the inlet air temperature sensor (at rear of rectangular cross engine inlet pipe- squeeze the retaining clips inwards to clear and pullout gently towards rear of car---disconnect 1/2"diam cam cover breather pipe---slacken large jubilee clip holding the flexible rubber connection to the large metal throttle body ----pull and wiggle the entire assembly towards the offside of the car ( where the driver sits) and you will have good access. You will see the 2 hooks on the cam cover that the cross pipe attaches to when you do this-catch the two rubber mounts also.

p.s. may not be the cause but costs virtually nothing to do as a first attempt to cure your problem.
 
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S80

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None at the monent, but there's an OM642 in the Jeep Grand Cherokee!
I'd put £100 on the engine loom seen it too many times before, if the MAF loom is faulty and shorting it will damage the MAF.


jib

And I'll put a £25 side bet on the 'evaporative loss' purge valve sticking open :D

Sits on the LH front inner wheel arch and has 'MOT' written on one of the ports (towards the motor). Try blocking off (sealing) the pipe end connected to the 'MOT' port (I used a bit of rubber glove!).
 

television

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Any more bets, only £25 a time,,I will hold the money :D
 

S80

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None at the monent, but there's an OM642 in the Jeep Grand Cherokee!
"'Oh why don't we play cards for her', he sneerily replied,
'And just to make it interesting, we'll have a shilling on the side'" :p
 
OP
T

tim124

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W124 E280 Estate/1995/2.8
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Further developments: engine actually 'stalled' (ie it just died on me) at a traffic junction, after running OK for about 15 minutes on the road (thus fulloy warmed up). No problem starting the engine, but something is obviously wrong, because it happened again later the same day when the engine was not fully warmed up. Still want to bet that £100 on the wiring loom?
 
OP
T

tim124

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W124 E280 Estate/1995/2.8
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Thanks everyone. Have taken out second mortgage to purchase a new loom and AMM, to be fitted by Indie next week. Will let you know if this deals with the problem (and you can then collect on the bets!).
 

coker

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Only just logged on and saw your problem - It sounds very similar to my E320 a while back - answer was regeneration valve!
 

jibcl500

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CL500,ML55,SLK280
Thanks everyone. Have taken out second mortgage to purchase a new loom and AMM, to be fitted by Indie next week. Will let you know if this deals with the problem (and you can then collect on the bets!).

I assume you identified the loom as being the problem prior to buying a new loom?

jib
 

kth286

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E320 Coupe 95
I assume you identified the loom as being the problem prior to buying a new loom?

jib



I was also thinking that - spooky eh !

A code reading would have been good as a first step.
 

S80

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None at the monent, but there's an OM642 in the Jeep Grand Cherokee!
I must say that if the loom on my 280E ever packs up, I won't be shelling out the £500-odd pounds on a bunch of wires and connectors :mad:

It'll be either a DIY repair or Grim Reaper time....

Of all the many cars I've owned during the last 30 years or so, I can't recall ever having to replace a wiring harness in this way - not even on Citroëns :)

Shame on you, M-B.
 
H

howellc

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Hi, interested to know if you have got it sorted. I have a similar problem and the diagnostic garage approach is getting expensive. Any help appreciated ??
 


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