tomknight1

Mercedes R Klasse starting and stalling problems

My 2016 Mercedes R Klasse with a gasoline engine is giving me fits. It's got almost 200000 km on it now. Sometimes it just won't start. Then other times the engine will randomly shut off while I'm driving. And when it does run it's rough. I'm thinking maybe something with the ignition switch or the car ignition system. Could a bad fuse cause these starting issue problems? I haven't checked the ignition coil yet but I guess that's next. Starter motor seems fine. I'm using the same ignition key I've always used.

4 comment(s)

I am not a mechanic, but I had a similar starting issue with my R Klasse. Have you considered it might be related to the fuel pump relay? That was the cause of my car ignition problems. Are there any warning lights on the dashboard when this happens? Also, is it more likely to occur when the engine is cold or warm?

Fuel pump relay, huh? I hadn't thought of that. No warning lights come on when it stalls. I guess it happens more when the engine is warm, now that you mention it. So what exactly did you do to fix yours? Was it a difficult thing to get to?

The fuel pump relay was indeed the culprit for me. Given that your problem seems to occur more often when the engine is warm, it does seem similar. Replacing it resolved the starting issue. I recommend you visit a workshop to make sure. They will be able to diagnose it correctly.

Thanks for the tip about the fuel pump relay. I checked and the fuse was defective. Changed it and now the Mercedes runs fine again. Cost me like 50€ for the fuse. Appreciate the help!

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