sounds like it'll turnover but no start after 3 cranks and white smoke wkly on 2008 Ford F-350 Super Duty

truck sounds like it's going to start but will not after 3 cranks ... battery is anywhere between 12.9-14.2 ... may turnover after trying 2-3xs but not always ... will start when it is jumped w/no problems ... also lost of white smoke eventhough it's run for over 100 miles in a weekend at speed over 60mph on country roads ... fuel injector pump or oil pump or can it be tank delamanation? HELP

by in Oswego, IL on November 19, 2012
2 answers 2 comments
ANSWER by on November 19, 2012
what motor could be alot of things. diesel o boy and if diesel do you have any codes?
COMMENT by on November 19, 2012
no codes r coming up .... it's a diesel 6.4 ... did system check and all good
ANSWER by on November 19, 2012
what codes are there?
COMMENT by on November 19, 2012
no codes ... did system check and everything ok