I have 2000 Bx1800 with 1850hrs. The tractor will turn over (strong new battery) but will not fire up.I am getting a good amount of black smoke. I checked the glowplugs they are 1.0 ohms and working. Sometimes it would start normal other times it would smoke a lot then fire up.Now it will not fire up and run.When it would run it would run fine, no smoke. I cleaned the fuel injectors less than a year ago have ran tractor since. I have adjusted valves and have ran trator since. Could it be fuel injector pump? Can the fuel pressure be checked? Thanks for help!