This repair manual covers 1991-2002 Saturn automobiles, including SL, SL1, SL2, SC, SC1, SC2, SW1, and SW2 (Station Wagon) models.
Book Excerpt: 1991-2002 Saturn SL, SC, SW (Station Wagon) Repair and Service Manual
The fuel system consists of the fuel tank, an electric fuel pump (located in the fuel tank), an air cleaner assembly, the fuel injection system and the hoses and lines connecting the components. 1994 and earlier Single Overhead Camshaft (SOHC) engines are equipped with a Throttle Body Injection (TBI) system. 1995 and later SOHC and all Double Overhead Camshaft (DOHC) engines are equipped with a Multi Point Fuel Injection system.
THROTTLE BODY INJECTION (TBI)
The throttle body system utilizes a single injector, centrally mounted in a carburetor-like housing. The injector is an electrical solenoid, with fuel delivered to the injector at a constant pressure level. To maintain the fuel pressure at a constant level, excess fuel is returned to the fuel tank.
MULTI POINT FUEL INJECTION (MPFI) SYSTEM
A signal from the Powertrain Control Module (PCM) opens the solenoid, allowing fuel to spray from the injector into the throttle body. The amount of time the injector is held open by the PCM determines the fuel/air mixture ratio.
Multi Point Fuel Injection uses timed impulses to inject the fuel directly into the intake port of each cylinder. The injectors are controlled by the Powertrain Control Module (PCM). The PCM monitors various engine parameters and delivers the exact amount of fuel required into the intake ports. The throttle body serves only to control the amount of air passing into the system. Because each cylinder is equipped with its own injector, much better control of the fuel/air mixture ratio is possible.
FUEL PUMP AND LINES
Fuel is circulated from the fuel tank to the fuel injection system, and back to the fuel tank, through a pair of metal lines running along the underside of the vehicle. An electric fuel pump is located inside the fuel tank. A vapor return system routes all vapors back to the fuel tank through a separate return line.
The fuel pump will operate as long as the engine is cranking or running and the PCM is receiving ignition reference pulses from the electronic ignition system. If there are no reference pulses, the fuel pump will shut off after two or three seconds.
The exhaust system includes an exhaust manifold fitted with an exhaust oxygen sensor, a catalytic converter, an exhaust pipe and a muffler.
The catalytic converter is an emission control device added to the exhaust system to reduce pollutants. A single-bed converter is used in conjunction with a three-way (reduction) catalyst. Refer to Chapter 6 for more information regarding the catalytic converter.
Subject: 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Saturn SL, SL1, SL2, SC, SC1, SC2, SW1, and SW2 (Station Wagon) service, maintenance, repair. ISBN-10: 1563925125 | ISBN-13: 9781563925122 | Haynes 87010