majablaze8
Mercedes ML rough cold start issue
4 comment(s)
majablaze8 (Author)
The check engine light is on. I haven't checked the codes yet, and I haven't touched the fuel filter. What kind of injector test are we talking about? Can I do it myself?
julian_lehmann1
Get the diagnostic trouble codes (DTCs) with an OBD II scanner. Many auto parts stores will do this for free. For the injector test, you can listen to each injector with a mechanic's stethoscope while the engine is running to see if they are clicking. This confirms electrical operation, not fuel delivery. A more comprehensive test needs equipment to measure fuel injector flow rates and spray patterns. I advise taking your vehicle to a qualified workshop for diagnosis and repair. A defective injection valve/injector is a likely cause.
majablaze8 (Author)
I took it to a shop, and they confirmed it was a faulty injector. They replaced it, and the cold start issue is gone. Cost me about 515€.
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julian_lehmann1
Poor engine running during cold starts in your Mercedes ML could be caused by a defective cold start injector. This provides extra fuel during start-up. If it's not working right, it can cause a lean fuel mixture.