However , since a diesel engine has no spark plug to act as an ignition source , operation on natural gas alone is technically impossible .
Natural gas is a very clean - burning fuel , which consists almost entirely of methane with sulfur content near zero .
Since a diesel engine has no spark plug to act as an ignition source , operation on natural gas alone is technically impossible .
Natural gas is a very clean - burning fuel , which consists almost entirely of methane with sulfur content near zero .