my sprinter (03)311cdi had the same problem,tried changing fuel filter,put on a hand primer,changed glow plugs and battery but still the same!!!that just left the injectors,found somewhere though that on the fuel rail there is a pressure control valve,that has three washers inside,if these are worn,the engine wont build up enough pressure to start.these costed a £5 from merc.im told this dsolves a lot of these problems,but unfortunately not mine.it was the dreaded injectors,which in itself is not a big job until you discover merc have problem with them sticking in the head!!!!these babies were welded in,we tried everything to get them out,in the end we had to break off the rocker cover and take off the head,then hope that when we knocked them out we didnt crack the head!!!we got lucky, a local engine specialist says this is a major problem now and they bought a deep freeze to help but it is still touch and go.we got two out ok and they were recon'd,but we had to buy two new injectors at £150 each.then there was gaskets rethreading all the holes,a new rocker cover £100,and just general hassle with timing etc.lucky enough my friend is a mechanic so the labour was cheap,but it was still very costly.this however WAS the problem and the van is now fine.don't know if this will help you or not,could be something different,seems a lot can go wrong with them!!!
mercboy1978, December 2007