A170 will not run

[fireski]

I have a problem with my wife's 33,000ml 2007 A class petrol. Whilst driving, at the same time as I switched the air conditioning off the car lost speed and came to a halt. (Just a coincidence?) The engine turns over and starts momentarily but then stops. (Starter motor disengages, exhaust vapours being momentarily visible but then engine just dies). There are no dashboard error messages or fault codes showing with diagnostics, all fuses are okay. I've disconnected the petrol feed pipe and petrol comes out when the engine is cranked.

Any suggestions as to what might be the problem will be gratefully received!

 

[grober]

A170 Starting problems can sometimes be causes by FUEL PUMP RELAY PROBLEMS may operate during cranking but not during run?? location here dont think they are too expensive to change
Bert Rowe, Lofty's homepage. A-class info, photo gallery, History
If you know what you are doing shorting out the terminals temporarily should answer the question

 

[fireski]

A170 fuel supply problem

Graeme, thanks for your speedy reply. I've now checked the relay and it is okay.

I've sprayed easystart into the air intake and the engine will continue to run and rev. At the same time, with the disconnected fuel pipe is delivering a satisfactory amount of fuel to the injector rail. When reconnected, diagnostics indicate that there is 2+bars of pressure in the injector rail which I have been told is okay.

Any further ideas as to what the problem is likely to be please?!