Increased power outputs in high performance diesel engines are being obtained by the use of increased boost pressures obtained from the engine's turbochargers. Reduced compression ratio because of high boost tends to cause cold starting problems and white smoke at idle and light load, especially with a cold engine. One method of alleviating these problems is to make use of glow plugs in the engine cylinders. Applications of glow plugs include a glow plug ignited natural gas engine, methanol DI engine, and IDI and DI diesel engines.This paper describes a glow plug control system that actually controls the glow plug temperature directly. This new control system is better than the systems currently fitted to IDI diesel vehicles. The glow plug controller maintains a constant temperature at the glow plug without the use of any sensor external to the glow plug. The glow plug temperature controller was used with great success to control the glow plug temperature at the required point without burnout in a glow plug ignited natural gas engine.