Pull off a wire from a spark plug, stick a screwdriver in it and lay it on the engine with a small gap. Have someone crank the engine while you watch for steady sparks from the screwdriver.
You must check for both fuel pressure and spark. If only one is missing, troubleshoot that system. More likely, if both are missing, suspect a defective crankshaft position sensor on the transmission bell housing next to the back of the engine (for 3.3L engines), or inside the distributor on the 3.0L V-6. The 3.0L distributors give very little trouble. Before getting carried away, crank the engine with the distributor cap removed and watch to see if the rotor turns. If it doesn't, suspect a broken timing belt or stripped teeth on the belt.
When no pulses appear from the sensor, the engine computer thinks the engine stopped running so it turns off the Automatic Shutdown (ASD) relay. That relay sends current to the injectors, coil(s), alternator field, and fuel pump or pump relay. Much like Ford's miserable inertia switch, this is Chrysler very effective way of stopping the fuel pump if a fuel line is ruptured in a crash.
The engine computer turns the ASD relay on for two seconds when you turn on the ignition switch, then again when it sees engine rotation, (cranking or running). It knows the engine is rotating by the presence of pulses from the crankshaft position sensor.
Saturday, August 8th, 2009 AT 3:31 AM