Jinxie,
not sure where to buy a manual at, google can reveal alot of places that might but theres no guarantee you'll actually get the right one. Personally i don't trust those sources and tend to look at the dealer for things like that.
Now as far as your starting problem some of the most common problems if the engine is turning over good is to check fuel delivery and engine cylinder compression and glow plug operation. (the best way to check compression is to use an adapter on the glow plug hole and attach the guage in that position).
compression should be: 469psi (minimum 412psi).
i would also check the glow plugs and make sure they are operating correctly. To check those you'll need a multimeter and check the voltage supply and plug operation.
supply voltage should be no less than 10.5v. You can remove the glow plug and apply 10.5v to it and ground and if it glows red then it passes as normal operation. Also check the connection plate (the long connecting bar across all glow plugs) and make sure it is not corroded.
One way to check if the engine will even run is to use starting fluid, spray a little bit in the air cleaner element (element still installed), crank the engine, if it starts and runs then the problem of no starting is most likely in the fuel delivery. If it does not start and run then you have bigger issues with fuel delivery like injection pump or injectors, or engine timing or compression which in this case your looking at major work that needs to be done.

Hi Swoop
Do you know where I can buy an online manual? Looking for the engine portion. Got a new starter.....forklift wont start. It has the Mitsubishi diesel. Cranks good.....smokes but wont catch or fire.
Serial number of the forklift is AT12B00094
Looking for fuel system info and valve set info.
The engine does have blowby.....14000 hrs.....so maybe it is completely worn out.?
Thank you

having a serial number from the dataplate would be helpful
but with that said they only show one diesel engine for this truck which is an S6S Series.
The CAT part number for the starter for this engine is: 32B6610301 starter assy.
There is also a bracket that goes with this starter so in case the one on your truck may be missing or broken here is the part number for the bracket also: M642X34071

You may can get the starter through TVH as a reman but the bracket is probably only available through caterpillar.
Note: TVH reman starters are a 50/50 chance you'll get one that is dependable. If you want to be sure just go OEM and get everything from caterpillar. You may be able to google those part numbers and find one from an independent seller.