My vehicle suddenly quit, then ran again after sitting a few hours. It has become unreliable, and will starve and die. This usually occurs on startup, usually after running. I am convinced it is starving for fuel. It does have spark. The fuel pump (NAPA) has about 20,000 miles on it, pump relay has been replaced, all fuses are intact, contacts are clean. Fuel pressure test shows no pressure. Pump does not run when ignition is turned on. I will pursue by checking all connections, but, assuming good connections, I am uncertain how to follow this up. Is there a common problem to look at first? If an oil pressure sender can prevent operation, can a jumper be used to bypass, therefore, verify this failure? Having asked this, shouldn't the oil pressure sender shutoff be bypassed on start, therefore, the vehicle would start, then die? In addition, does the oil sender shutoff the injectors versus the fuel pump? It seems unlikely that a dirty filter would prevent pump operation. Can a fuel pressure regulator prevent all operation of the pump, given no fuel pressure? Can a jumper safely be used to operate the pump for testing purposes? If so, where to connect, starting at the relay (for tracing purposes)? Relay connector legs are 85, 87, 87A, 30, and 86. Replies appreciated.
Sunday, September 23rd, 2007 AT 12:32 AM