Fuel Control System
An electric fuel pump (located inside fuel tank) supplies fuel under pressure to TBI unit. A fuel pressure regulator inside TBI unit keeps fuel available to injectors (inside TBI) at a constant pressure. Unused fuel is returned to tank.
The fuel pump is controlled by the ECM through the fuel pump relay. As a back-up system to the fuel pump relay, the fuel pump can also be turned on by an oil pressure switch. If fuel pump relay fails, engine can still be started after oil pressure reaches 4 psi (.3kg/-cm2 ). A defective fuel pump relay can result in long cranking times, particularly in cold weather.