Hello, I have a Nexen FD25 (D22062) I have been working on and it kicks out loads of black smoke when at 3/4 throttle? She starts first time every time and runs smoothly UNTILL I hit three quaters throttle then I hear a knocking and excessive amounts of black smoke. I have adjusted the valve gap to 0.4mm as stated for the 4JG2 engine I have also had the injectors serviced by an injector specialist. I have tried to rotate the mechanical fuel pump but did this while the truck was not running. This didnt seem to help at all? is it safe to rotate whilst engine running? The truck has only done 3665 hrs. Any help would be very much appreciated.
Thanks in advance ;-)