First, welcome. Dont sweat it, tons of guys here that know these engines amazingly well. We can walk you through any issue.
Stick around after this problem is solved to learn from our mistakes, and know that most diesel shops do not understand this engine and will do things the way newer diesels are designed and that will cost you big money to learn their mistakes.
Originally On top of the engine is a plastic cover that says hides the middle of the engine. Get that out there- most never reinstall it.
in the rear center of the engine you will find the FFM (fuel filter manager) it has a cartridge fuel filter, in it and a few fuel hoses going through it. Take a look if fuel is leaking from it, or the hoses coming off of it.
Fuel leak obviously danger for fire, but also can keep the engine from running properly. Something different about diesels is if a hoseclamp or something is loose and that line has suction rather than pressure, it can suck in air and not let the engine run right even if it isn’t dripping fuel. So consider the easier to fund fuel leak a good thing because they are easier to find
A recently replaced fuel filter is a common source of fuel leaking when the large nut on top didn’t get screwed in staight.
There is a valve by the thermostat for draining out water from the fuel filter that could be slightly open. Follow the hose from FFM to it and check valve closed fully and hose condition to it.
If you get to replacing fuel line because you find defective hose- a couple things to consider.
Only buy sae30r9 hose to handle the modern fuel. The old hose doesn’t stand up long term to the new fuel - so deteriorating hose could be your issue.
It is 3/8 line feeding to the ffm, and 5/16 line coming out going to the drain and another 5/16 line coming out going to the ip (injection pump). -however many people upgrade that ip line to a 3/8 for better flow helping with longer parts life & drive ability.
then there is a 1/4” line that comes out the ip to return to tank. There are 1/8” lines on each injector thatconnect to each other then to the same return line as the ip return. If the 1/8 lines leak, they usually leak down the side of the engine. If the 1/4” part is leaking, or any of the 5/16 line, the ffm, or it’s connections - They leak into the center of the engine which has a valley. The fuel goes to the back of the valley where a hole is drilled that lets it leak down onto the flywheel and clutch or flexplate and torque converter if auto trans. Then it gets to the flywheel inspection cover on the bottom and comes out that hole.
Take pictures and post here by using the button below this box when typing that says “attach files” and choose “full image”. Or a video to YouTube, bitchute, etc and post the link here for us to watch. Ask tons of questions- we all had to start learning some where.
Depending where you live- a few guys here can meet up to help. I am in the Las Vegas Nv area.