Central Sequential Fuel Injection (CSFI) Assembly

WARNING: This page does not describe the selected car, but rather 33 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.

CSFI assembly is a non-repairable injector unit consisting of a fuel meter body, fuel pressure regulator, fuel injector and poppet nozzles with fuel tubes. CSFI assembly is housed in the lower manifold assembly. Fuel pump and pressure regulator maintain fuel pressure at 60-66 psi (413.7-455.1 kPa) under all operating conditions.

When injector is energized, pressurized fuel passes down fuel distribution tubes to poppet nozzles located at rear of intake valves. Fuel pressure forces poppet valves open, spraying fuel into cylinders when intake valves are open. As fuel pressure drops (due to all poppets opening or injector de-energizing), poppet nozzle spring pressure closes poppet nozzle until pressure again builds high enough to overcome poppet nozzle spring pressure. Excess fuel is returned to the fuel tank via the fuel return line.