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isabellarichter1

Mercedes M Klasse Cold Start Nightmare

My 2010 Mercedes M Klasse with a gasoline engine runs rough on cold starts and takes a few tries to get going with only 38955 km on the clock Once warmed up, it's fine I've tried injector cleaning additives, but no dice Any ideas about these cold start problems or rough idle issues I'm not sure about fuel injection system diagnostics

Summary of the thread

A 2010 Mercedes M Klasse experiences rough running and difficulty starting when cold, despite having low mileage. The issue resolves once the engine warms up. Initial attempts to fix the problem with injector cleaning additives were unsuccessful. The problem was identified as a faulty cold start injector, and a repair was quoted at 515€.

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4 comment(s)

walterschubert8

Sounds familiar I had similar hard starting and rough idle issues with my Mercedes a while back Check your fuel trims, especially short term during the cold start Could be a leaky injector causing flooding I'd also compression test it What are the LTFTs looking like

isabellarichter1 (community.author)

Fuel trims, huh I'm not really equipped to read those Is that something a regular OBD2 reader would show, or do I need something more specialized Compression test I don't even have the tools for that So you really think its fuel injection related

walterschubert8

Yeah, you'd need a decent scan tool to pull those fuel trims The cheapo readers usually won't cut it Seeing as you don't have the tools for compression check, the injectors are probably the culprit, better take it to a shop But hey, injector cleaning is worth a shot if you're feeling lucky It may solve the hard starting problem, but my experience says, better change the part

isabellarichter1 (community.author)

Cheers for the insight Took it to the shop, and you nailed it – faulty cold start injector They quoted me 515€ for the repair, so I'm getting it sorted Glad to be rid of these cold start problems at last

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MERCEDES

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MKLASSE