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OK gurus,
I posted this in the w251 forum, but there are not that many seasoned troubleshooters there, so I am hoping you all can shed some light...

Wife drove to the grocery store. She came back to the R and upon turning the key, the ignition sequence just cranked the engine for about 10 sec then stopped.
No check engine light or any abnormal signs leading up to failure. I had a brand new crankshaft position sensor available to me so I brought the jack, stand and tools to the parking lot and replaced the CPS to no avail, same behavior. Next, I went to the local Advance Auto to borrow an OBDII scanner. Again, no avail, since there were either no fault codes, or this reader is not capable of reading them...
Having already performed the above troubleshooting, please tell me if my logic is correct...
Since the engine is cranking but not starting, is it safe to assume it's not getting fuel? Temp today was around 70˚F, so if there was a pre-glow failure, the engine should still start after cranking for 10+ secs. If fuel is the problem, are there any other suspects other than fuel filter or fuel pump?
Finally, is it possible that the OBDII is not cutting it and I need the STAR Diagnostics machine to read any possible codes?
Thanks for reading this far and providing your input!
-Robert
 

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We don't have designated section for diesels on this forum, so proper section is the General.
You are right that the only reason diesel doesn't start in such conditions is lack of fuel, but than fuel injection is controlled by the computer. The computer might not open injectors for several reasons and CPS is just one of them. Per my experience with E320cdi faulty fuel pump would trigger warning light.
Bottom line, the engine management is pretty complicated and if OBD doesn't show any codes, you need Star computer.
Good luck
 
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