c43 ticking noise on idle and engine hunting

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zaen1

Active Member
Joined
Apr 10, 2015
Messages
91
Location
Birmingham
Car
c200 sport/c43 amg
Hi all.

Started up my c43 today and noticed a ticking sound coming from the engine bay,had a look under the hood and it seems to be coming from the front left side around the ABS pump assembly. The sound is not like ticking you get from noisy tappets more like when you testing a spark plug to see if its firing or not. Anyone had any experience of this or know what it could possibly be, also the car is slightly hunting at idle,this has been going on for a couple of months,its not much but its noticeable,probably a fluctuation of 50-100rpm. Have only serviced it in November,oil,air filters,spark plugs. Could it possibly be the coil packs or leads for the fluctuation. any help would be much appreciated. Thanks in advance.
 
Could be the purge valve. They can tick and cause a vacuum leak. (see if you can suck through it)
Easy to check, un-plug it and blank off the pipe to the inlet manifold. That's what I've done with mine while I wait for a new one.
 
Hi Richard,could you tell me where the purge valve is located and would you know the price for a new one. thanks
 
Left side inner wing maybe under a cover if you have one on the strut tower.

A smallish valve with an electrical connector and two pipes, one going to the inlet manifold, the other disappearing under the scuttle, on-route to the charcoal canister behind the wheel arch liner.

I think you'll pay circa £100, they'll be a part number on it.

Photo attached so you get the general idea.
 

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Ticking will be the unit pointed out above, it is not faulty as the noise is standard and will stop after a while.

As for hunting/slight misfire leads would be my guess.
 

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