I suspect you are expecting to have twelve volts to the fuel pump when you should not have it. That will only be there for one second when you turn on the ignition switch, then again when the engine is rotating, meaning cranking or running. If there was twelve volts there all the time, that would pose a serious fire hazard if a fuel line got ruptured in a crash.
For a crank/no-start, you have to check for spark too. About 95 percent of these no-starts are caused by a loss of injector pulses, fuel pump, and spark. All of these systems get their twelve volts through the automatic shutdown, (ASD) relay, and that is turned on by the engine computer. If you have a scanner, you can view the state that relay has been commanded to by the computer. If you do not have a scanner, the fastest way to know if the ASD relay is turning on is to back-probe the dark green/orange wire at the ignition coil pack, any injector, or either smaller terminal on the back of the alternator. A test light works best for this because most digital meters do not respond fast enough. If you see that twelve volts show up for one second when you turn on the ignition switch, the relay is working and the computer has control over it. What is important is if it comes back during cranking. If it does, you have an ignition system problem or a fuel problem, but not both. More commonly, if the twelve volts does not come back during cranking, it is because the engine computer is not seeing a signal from the crankshaft position sensor or the camshaft position sensor.
Aug 3, 2017 at 7:27 PM
