Happy to hear about the fuse, but don't jump the gun on the fuel pump. Too many are replaced when they aren't needed. I understand about the multiple mechanics and it is understood the camshaft sensor was not related to the current problem. I needed to state my case because that is another thing I read about a lot. People understand they might have to go to a doctor multiple times to figure out a diagnosis, but they hold their mechanic to a higher standard. He's considered incompetent when he doesn't find the answer right away.
Back to your fuel pump, each time you turn the ignition switch to "run" you should hear the hum of the fuel pump for one second. That's the proof the pump is starting up. It won't turn on again until the engine is cranking or running. If you become accustomed to listening for that you should notice you're not hearing it when the engine doesn't start. Banging on the bottom of the gas tank while a helper cranks the engine will often get it started. It is real common for GM fuel pumps to die while you're driving, but Chrysler pumps almost never do that. Once they start up they will continue running as long as the engine is running.
If you hear the pump running but the engine still doesn't start, first turn the ignition switch all the way back to "off", wait a few seconds, then try again. If that works every time after a no-start condition, fuel pressure might just be bleeding off while the car was sitting. That is not serious except for the inconvenience. During engine cranking the battery voltage is drawn down which makes the fuel pump run slower than normal. It can't build up pressure fast enough for fuel to squirt from the injectors. Cycling the ignition switch multiple times lets the pump run for a total of a few seconds before you crank the engine. That gives it time to build up enough pressure.
Normally that pressure in the system will stay there for many weeks, but it can bleed down due to a leaky injector, fuel pressure regulator, or check valve in the pump.
If you DO hear the fuel pump run yet the engine doesn't start, there are two things you can do to start the diagnostic procedure. One is to have someone show you how to check for spark. It's easiest with a helper to turn the ignition switch while you watch under the hood but there are ways to do it yourself. The second thing is to measure the voltage on the dark green / orange wire at any one of the injectors or the ignition coil. You should see 12 volts there for that same one second after you turn on the ignition switch, then again when you're cranking the engine. If it doesn't come back during cranking, the camshaft and crankshaft position sensors would be the first suspects. I don't think that's what's wrong now because it's more common for those sensors to fail after they warm up.
Saturday, February 12th, 2011 AT 11:27 PM