Exhaust Gas RECIRCULATION: Description

On 1974-78 models, two basic EGR systems are used. Federal models use an EGR system without a vacuum amplifier, while California models use a vacuum amplifier controlled EGR system. The EGR system consists of EGR valve, a coolant temperature thermostatic vacuum switch, vacuum solenoid valve (if equipped), throttle valve micro switch (if equipped), vacuum amplifier (if equipped), and various connecting hoses and pipes.

In addition, all models also have an EGR maintenance reminder system which will turn on a light on instrument panel every 15, 000 miles.

All 1979 Federal 240 models, are equipped with an Exhaust Gas Recirculation (EGR) system. This system is designed to reduce the formation of oxides of nitrogen (NOx). This is accomplished by recirculating a small amount of exhaust gases back into the intake system where it mixes with the air/fuel mixture. By adding these gases to the air/fuel mixture, the combustion temperatures are lowered, thereby reducing NOx emissions. The system consists of an EGR valve, a thermal control valve, a vacuum amplifier, and the various connecting hoses and pipes.