Your question is a bit unclear as to exactly what changes were made to the setup, but the tutorial runs quite quickly as it is, so I am curious about the purpose of the changes? Most of the tutorials were created with older versions of Chemkin and so may not work optimally in newer versions where some of the numerics have changed.
Below are the current default settings for DI engine. If a project has been updated to a current version of Chemkin, these sometimes may work better than the original settings. The solver absolute tolerance can occasionally be increased to 1.0e-08 to allow convergence; this is still adequate to capture species concentrations.