2002 Isuzu Trooper engine fuel filter

I changed the engine fuel filter on my 3.0td trooper and now it will not run the engine fuel filter is mounted on the engine close to the sump and contains oil even though it is not the main oil filter for the engine the main fuel filter on the bulkhead is ok the engine fuel filter is also known as the 2nd(sub)filter any advice would be a great help Regards ERichard