2005 C200 CDI not starting issue

[Benstanley86]

Hey everyone a friend of mine has a 2005 C200 CDI on 140k and it won’t start, turns over but won’t start (well very occasionally will start) it went into the garage and they said it was a faulty glow plug relay but wanted £400+ to fix. I’ve said I’ll do it for her but am having issues locating it to get the correct part number. I think it’s an OM646 engine and that is on the inlet manifold accessed from underneath but I can’t seem to locate it anywhere.

many help welcomed!

thanks

Ben

 

[mersum1es]

I don't think it is glow plug relay. At these temps it will start without them. Longer crank yes, but eventully starts. See fuel pressure at live data. If its low, it is leak somewhere. If pressure is enough, crank/cam sensor sync should be checked.