Absolutely. If your left head light doesn't turn on do you replace it or do you check to see if ALL the lights are not turning on? You got stuck on the first thing you suspected, the fuel pump, but you never bothered to look further at other things in common with it. If a crankshaft position sensor quits intermittently, the Engine Computer will think the engine stopped rotating so it will turn off the fuel pump. Without the crank sensor's signal the computer doesn't know when to fire the ignition coil so you have no spark. The fuel pump and the lack of spark are the symptoms. They aren't the cause of the problem.
In this case there's actually four circuits; the fuel pump, the ignition system, the injectors, and what triggers them. You're spending your time in the fuel supply system, (which could be the one with the problem), but first you need to see if other systems are shutting down. That would tell you to look at what they have in common.
If you still have spark when the engine quits, then you know anything in common is not the problem and to diagnose the fuel supply system. One potential clue is if only the pump quits while driving the engine will typically surge and sputter for a few seconds before stalling completely. With an intermittently failing sensor the engine will usually stall abruptly. It may fire again for a few seconds as you're coasting to a stop, then stall again multiple times but loss of spark causes instant changes. Loss of only fuel pressure causes gradual loss of power over a few seconds. That can be hard for car owners to distinguish but it is one of the things experienced mechanics look for.
Sunday, September 23rd, 2012 AT 8:53 PM