W203 C220 coupe, just won't start

[Dogfish]

W203 C220 coupe, just won't start. She ran well until Thursday night and come Sunday, and cold weather, she refuses to start. She has no under tray at the present though.
I'm going to spray easy start tomorrow morning and see if that tempts her into life.

If not, I guess it's going to be a case of check the glow plugs for open circuit. Where is the control box situated? I could test the wires back to the box and check the current draw with my multi tester. Looks relativly easy after seeing this link by Dave Pemberton. http://forums.mercedesclub.org.uk/showthread.php?t=29073&highlight=w203+start

I don't think its a fuel problem as I had the fuel tank senders and pumps done last year. Unless the high pressure pump is dead.
I also thought that the crankshaft sensor is a probable culprit, my son says he will test it on the osciliscope if I get the operating parameters? I was just going to connect a multi tester up to it and pop the sensor end in a small puddle of hot water to see if the resistance changes! Worked on my Triumph Trophy years ago.

Son also bought a bluetooth elm327 box (?) to interrogate the car. I think star may actually be required here.

Nice change driving my daughters 105 while she is away at Uni, I wonder if it handbrake turns as well as my old mini?

Kind Regards

Si...

 

[Steve@Avantgarde]

Si

I would say you have a fuel pressure problem!! You need to check the fuel pressure before you do anything else!

 

[Dogfish]

Thanks Steve.
I was reading this thread about the HPPump. http://forums.mercedesclub.org.uk/showthread.php?t=70320&highlight=w203+start

Is there a way of determining fuel pressure without tools? How would you do this please.

Kind regards.

Si...

 

[mercedes13156]

Hi. I agree with Steve. However, before you start taking things to bits, my own experience of a similar problem on a W203 coupe was that one of the electrical connectors on the the injectors wasn't fully home and wasn't allowing the engine to start. It started first time after clicking it fully home. Another time, it was the electrical connector on the left of injector Nr 4 that had come loose because I had leaned on it accidentally.

 

[Dogfish]

Thanks mercedes13156.
Ive wiggled all the connectors inc crank position sensor, still no joy but thanks anyway. It was worth a try!
There is diesel in the pipes and I don't see bubbles lurking anywhere. The pump is not leaking externally however it could be knackered and need a repair kit as Steve suggests. Need to find a way to test the pressure without tools...

I found the Glow plug control box, has anyone got the pinouts for the plugs so I can test in situ to start with.

Thanks

Si...

 

[mercedes13156]

It's almost certainly not the glowplugs. Even if you have no working glowplugs at all, it might just take a couple of seconds more to catch.

 

[Steve@Avantgarde]

Easy Start!!

If it runs after a squirt you have fuel pressure and you know its an issue with an injector or something like that.

If it wont run on easy start, then its likely you have no fuel pressure.

 

[mercedes13156]

Did it start?