Anybody know how to troubleshoot a diesel?

[b3lha]

I'm babysitting my friend's Vectra 1.7td POS while he is away on holiday. He told me that it's hard to start in the mornings because air gets into the fuel system. He said if it gives trouble just to spray some quickstart in the intake or just keep cranking it until it starts.

Anyway, I made the mistake of parking it at the end of the drive, blocking my other cars in. And nothing I can do will make it start. I spent two hours messing about spraying quickstart and cranking it but no luck. It fires momentarily on the quickstart and then dies immediately.

When the battery went flat from all the cranking, I got upset with it. I put my legacy battery on it and used the starter motor to inch it out of the driveway into the road. I've just left it by the side of the road for now. But if I leave it there too long it will get towed or burnt. Which I can't help thinking would be the best thing for it, although my friend might disagree.

I need to get it started so I can move it to the back of my driveway where it's not blocking anything. I know almost nothing about diesel engines, but it seems to me that there isn't much to go wrong. Provided the fuel gets into the cylinder, the compression should ignite it. So what is the most likely problem with the fuel system? There are lots of pipes in the engine bay that may or may not be fuel pipes. I really don't know where to start. (no pun intended)

Each cylinder seems to have a metal pipe and a thin braided pipe running to it. I pulled off the braided pipes and there was no fuel in them. Does a diesel have separate piping for fuel and air perhaps?

I'm going to give it another go after work tomorrow and if I can't get it going I'll have to call out the AA. Any suggestions welcomed.

Enduring a 10 year old Vauxhall reminds me to be thankfull for my 16 year old Subaru.