Theory and Operation: Theory/Operation: Introduction

This article covers the basic description and operation of engine performance related systems and components. Prior to diagnosing vehicles or systems with which you are not completely familiar, read through this article.

Bosch CIS-E fuel injection system uses Continuous Injection System (CIS) for fuel delivery and electronic controls for mixture adjustment. Mechanical portion of CIS-E system consists of Mixture Control Unit (MCU) which is also known as the fuel distributor, airflow sensor plate, diaphragm pressure regulator, fuel injectors, fuel pumps and filter.

Electronic controls consist of airflow sensor position indicator (potentiometer), Differential Pressure Regulator (DPR), thermo time switch, coolant temperature sensor, Electronic Control Unit (ECU), oxygen sensor, auxiliary air regulator, idle speed stabilizer control unit, cold start valve, idle speed boost valve.