Partial Lean Burn System

This system, used on models equipped with 4K-E engines and 5 speed manual transmissions, includes an engine load sensor which allows the EFI computer to provide leaner than theoretically ideal air/fuel mixtures when the engine is running at steady speeds under light loads. In addition, a Mechatro spark control (MS) igniter is used which allows the EFI computer to control spark timing when the system is operating in the lean burn mode. For diagnosis and testing of the MS igniter, refer to "Electronic Ignition Section."