A gaseous fuel-enriching subsystem for an internal combustion engine includes a supplemental intake conduit to a an intake manifold internal combustion engine. Such supplemental input is provided with numerus apertures therein. An exhaust gas conduit from the internal combustion engine annularly surrounds the intake conduit permitting fuel values from exhaust in the exhaust conduit to enter the supplemental intake conduit through such apertures. A water supply input to the supplemental intake conduit, at a end opposite to the location of the manifold, provides a further fuel input to the supplemental intake conduit in that water from the water supply is evaporated and then hydrolyzed, separating the water into its chemical constituents of hydrogen and oxygen, thusly producing an enriched gaseous fuel mixture with the recycled exhaust gas which is fed to the manifold.