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I've had intermittent hard starting problems with my wife's Mercedes over the past year.
It doesn't seem to matter if its summer or winter. But she claims if its parked overnight in the garage it starts more often on the first try.
I have been on and off trying to fix the issue and have replaced following parts this year so far:
new glow plugs (NGK9970 CZ303), glow plug controller module, fuel filter, the 2 fuel hoses connecting to the fuel filter, main battery, air filters
I also replaced/ inspected following items more as a preventative measure for the future since the ML already has 265K on it:
crankcase ventilation cover, pcv valve, camshaft position sensor, crankshaft position sensor, inspected timing chain tensioner, cleaned MAF sensors
I own the Youcanic UCAN-II-B Pro Scanner and have had a bunch of old codes stored that I cleared and none came back after a week of daily driving.
There is no fault codes present right now.
Do the camshaft and crankcase sensors need to be relearned and how?
Is there a way to troubleshoot the low pressure fuel pump with a scanner?
(I can hear the pump running when I turn the ignition on without starting the car)
Any recommendations on what I could check, that might get me closer to fixing the intermittent hard starts?
I have a 2009 ML350 4matic W164 and for over a year I had increasingly hard starts as well. Eventually the car 1 day would not crank at all. Thought it might be the key ignition module in the dash as I had read a lot of stuff about that going bad and ways to fix it cheaply. In the end, it was the starter. New starter 8 months ago and car now cranks so friggin fast I still can't believe it. I always thought a starter either worked great or didn't work at all and my Autel Scanner did not pick up anything about the starter. I was wrong on that!
Thanks for your suggestion.
I was thinking of ways on how to check the starter to rule it out being the culprit.
Changing it seems to be quite the job if you are doing it in your driveway on ramps.
Will have to get a YouTube education first and check it first before diving into fuel pump, low pressure, rail pressure and so on.
Heiko - sweet ride! There is a way to test the starter. Has to do with using a stout wire and arcing a particular fuse. I can't remember exactly how it was done but when I remember watching a youtube video but feeling uncomfortable doing it myself. When I had the vehicle towed to the dealership up the street, the mechanic came out and performed his tests with a multimeter and then announced it was the starter and it was.
11-08-2023, 02:35 AM
