Why Do Diesel Fuel Injectors Fail? There are two major causes of diesel fuel injector failure associated with the properties of the fuel itself: excess wear and deposits. Excessive Wear One mode of injector failure is excess wear. Prior to 2006, diesel fuels in the United States contained relatively high amounts of sulfur. This sulfur comes from the crude oil refined … [Read more...] about 2 Common Reasons Diesel Fuel Injectors Fail (And How To Prevent It)