Diesel losing power- help

[kemess]

Thanks for reading. I am new to this forum. I have a problem that I hope one of you forum experts can help me figure out. I own a HINO FA1517 cabover diesel. It is a 4 cylinder/turbo. I lent it to a friend and while driving it, the truck lost power and started to make a slight ticking sound. I took the truck to a "professional" after $500 they proceeded to tell me that the truck needed a new motor and turbo to the tune of $14k. Immediatley they said they would be happy to "take" it off my hands and dispose of it for $100. Then they tried to sell me a new truck. The engine on this vehicle has 102,000 miles on it. When I pushed them on what they did to diagnose the problem it turns out they did nothing more than start it and listen. The $500 bill was for basically nothing. I had no choice but to pay the bill and pay a tow truck another $250 to tow it home. Since then I removed the valve cover to check valves/springs etc. All seem to be functioning properly. I have had a few people make suggestions and am looking for opinions before I stick more money into this truck.
Here are a few thoughts
1)change all the fuel filters etc
2)Could be a sensor on the cab over design that went bad
3)Throttle cable
4)Governor
5)Exhaust brake
6)mapping computer etc.

Do any of these things seem to make sense? Any other thoughts? Things to check? Any resources on how to test compression?

Thanks for any help. I am obviously not mechanic, just a guy making sure I was not being taken advantage of.
Thanks
Kevin

[sdan27]

With low power, the first things to check are always fuel filters and air filters. I don't have much experience with Hino engines but with diesels I've worked with in the past, you either have to remove the injectors or the glow plugs ( if equipped ) and adapt a compression gauge to and crank over to get a reading. Just like taking out the spark plugs and adapting a compression gauge to a gas engine. If the engine has a throttle cable, it is most likely a mechanically controlled engine and I doubt it would be an issue with a sensor. Might be worth trying to locate a Hino dealership and talking to some of the service guys there to see if they can help you. Sounds like the place you originally took it to didn't really know what they were doing. A few things you can check out anyway.