Thomas with Mercedes won't start.

[bridg73988]

Hello, let me start by apologizing for the limited info I have thus far. I am in the process of purchasing a bus from somebody and they also have a 2005 Thomas with a Mercedes engine that suddenly decided not to start. The man is willing to give me a nice discount off my bus if I can help him with this problem. The bus is about an hour from me and I have not seen the problem first hand. What I have been told is it was running fine, the bus was parked for a couple months and now it cranks but won't start. He replaced the fuel filter which didn't help. They have it sold if it will start. Does anyone have any suggestions of anything to try or where to start? I am an auto mechanic but don't know much of anything about diesels. Thanks for any help!!!

[brokedown]

THere are only a few things that will stop a diesel from starting.. At least, only 2 that aren't completely obvious (someone took the head off!) It's either not spitting furl into the cylinder, or compression alone isn't enough to start it from cold.

#2 would suggest it isn't heating the glow plugs.

#1 could be more things. Injection pump not functioning properly (broken, or not getting the control signals), fuel literally not making it to the pump for reasons (leak, bad fuel pump, etc).

If it "was running" and after sitting for a few months "won't start", my instinct would be that there was a pressure leak in the fuel line and all that sweet sweet diesel ran back down to the tank. I'm not familar with that powerplant but if its using a "pull" type pump rather than a "push" type pump, it might never actually pull fuel all the way up if there's even a little bit of air leaking in.

BTW - replacing the fuel filter implies that the fuel system got filled with air, if the guy isn't knowledgeable about getting it full of fuel again he'll likely never get it to start. Lots of ways to push fuel up if its a pull system.