Turning over but not starting
Thread Starter
Newbie
Joined: Feb 2019
Posts: 2
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E280
Turning over but not starting
So I know there are a million possible reasons for this but perhaps with a little background someone might have an idea where to start.
I'm going to take it to my local Mercedes mechanic (not a dealership) but I've only just found him so I'd like some ideas before I take it to him.
2007 E280 with 304,000 km
Just bought it in October.
Been a daily driver since with no issues.
Had the speed detector rings (ABS etc) replaced in December. (at the same place I am going to take it to)
He told me I would need a new thermostat but that it was not crucial but expensive so I decided to wait.
Cabin does not heat as fast as it should in the winter but it is nothing uncomfortable so I have been fine.
Suddenly the other day it would not start.
I had driven it just the previous evening home from work with no issue.
It turns over but the motor will not start.
we have had a couple of cycles of freezing, above freezing and then below freezing again. The above freezing periods were very wet with lots of water on roads.
It had turned cold again overnight the night before it would not start and it has remained cold since so I have not had the chance to see if it might start in "warmer" (+5C) temps.
No idea if any of this is relevent but just in case there it is.
I'd love to know if anyone has any ideas...
Thanks
Dan
I'm going to take it to my local Mercedes mechanic (not a dealership) but I've only just found him so I'd like some ideas before I take it to him.
2007 E280 with 304,000 km
Just bought it in October.
Been a daily driver since with no issues.
Had the speed detector rings (ABS etc) replaced in December. (at the same place I am going to take it to)
He told me I would need a new thermostat but that it was not crucial but expensive so I decided to wait.
Cabin does not heat as fast as it should in the winter but it is nothing uncomfortable so I have been fine.
Suddenly the other day it would not start.
I had driven it just the previous evening home from work with no issue.
It turns over but the motor will not start.
we have had a couple of cycles of freezing, above freezing and then below freezing again. The above freezing periods were very wet with lots of water on roads.
It had turned cold again overnight the night before it would not start and it has remained cold since so I have not had the chance to see if it might start in "warmer" (+5C) temps.
No idea if any of this is relevent but just in case there it is.
I'd love to know if anyone has any ideas...
Thanks
Dan
Super Member
Joined: Jul 2015
Posts: 795
Likes: 189
From: San Diego, CA
2016 E350 Sport; Mom Wrecked the 2008 E350; sold the 2002 C320
You are correct - if the battery was dead, it would not turn over. As others suggested, the crankshaft position sensor is the most likely culprit. However, if that does not fix it, you are better off having a diagnostic done because like you said, it could be one of a myriad of things. In my case when this happened to me it turned out to be a very rare failure - the throttle body.
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,224
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
I am not familiar with the engine, but in each situation of non-starting the easiest way to start troubleshooting is read the fuel pressure.
Some cars will show it on scanner, for older you need $19 gauge.
Bad CPS usually start acting on hot engine, while still working on cold one.
I never could get solid confirmation, but working CPS in no start situation should move tachometer a little?
Some cars will show it on scanner, for older you need $19 gauge.
Bad CPS usually start acting on hot engine, while still working on cold one.
I never could get solid confirmation, but working CPS in no start situation should move tachometer a little?
