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Engine idling rough

11432 Views 16 Replies 7 Participants Last post by  Aristophanes
Anyone's 453 run a bit rough at idle? I bought the car brand new and it wasn't this rough for the first 5k miles. I have tried different gas, etc asll the same. I took it to Mercedes of Sacramento and they said 2 things. 1 they have never even had a newer smart in there and 2 it was normal. If I rev it to like 1200 RPM's it is fine and smooth but just sitting at a light its definitely rumbling.
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There is a known issue with a solenoid guys I have the same car (0.9 tce Renault engine) and rough idle too ,you can take the part out and clean it, personally i ordered the part : smart : A2811530159 / Renault : 237964892R

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And here is the solenoid in question, installed today really easy as per the evilution guide.

personally it DID fix my idle issue and engine is running stable @900 rpm(just below 1K)

went with Renault as I found it discounted from a Renault parts shop (£60) as opposed to the Renault / Smart dealerships (£200+) also mounting was really easy,it is hold only by a 8mm bolt.
it took me less then 15minutes in total.

would reccomend to anyone who has symptoms of missfire/rough idle,and likes to fix stuff By himself like I do 😁


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i bought mine off eBay mate, and actually it came from UAE lol there was a shop with a huge discount there,actually was about £29 + £28 the shipping,as I couldnt find that part anywhere in the UK for less than £100+

type the part code on eBay or google ,eiher Renault or Smart and have a look the market there is huge you will find plenty of options 😁
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If you want I can give you the shop name on eBay and you can check if they ship in the US.
Guys by the way this is covered by Smart/mercedes dealers or from wherever you bought the car from.
even with the warranty expired there are cases that they replace them, it is a very well known manufacture issue.

mine is a ‘17 and bought second hand hence no warranty.
Had same on my secondhand 453. I bought solenoid from Smart / Mercedes £94. But the lower part that goes into the engine block was well siezed in. I couldnt get it out. Took to dealer, took them two & a half hours to do what they said takes half an hour. Cost £211.
mate that’s extremely cheap from a dealer £94,from which Mercedes was it?

Yes there is build oxidation like white salts builded around it, it is a chemical reaction resulting from aluminum and steel contact.
all I did was remove the 8mm bolt that holds the solenoid, and spray little bit of WD40 around the solenoid(there is a tight rubber gasket in the solenoid so no fear from dropping inside the engine ) let it soften those white salts for a minute and then wipe it with a clean microfibre and kindly rotate the solenoid before pulling it up,then wipe again making sure nothing can drop in the engine while you re pulling it off.
by rotating the solenoid the little ear (the one that the bolt goes in to hold it in place)is breaking loose all those white oxidation salts and they even become like a white cream (because of the wd40) easy to whipe.
that way it rotates freely and you can gently pull it up.
total time :15 minutes
Of course any Dealer can claim x hours,as they are charging labour by the hour.
Fair enough, mine came out relatevily easy and in one piece.
if it splits then I guess it will be a bit harder to remove, mainly becacuse of the snug fit of the rubber gasket that isolates the solenoid in the engine.
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