The pump is a PFR type injection pump.. its timed with steel shims under the pump to raise or lower the point of injection..
UNLESS the block, cam or crank has been replaced.. no need to change it.. or check it for that matter..
If your experiencing heavy smoke or hard start.. check the fuel supply first.. then the injectors and do a compression check while the injectors are being checked..
and finally, get the pump looked at..
OH, forgot to mention.. check the valve setting BEFORE getting into the fuel system..