Sorry for the delay in replying.
Sounds like it's working properly. The injector(s), coil(s), alternator field, O2 sensor heater, and fuel pump or pump relay receive 12 volts through the Automatic Shutdown (ASD) relay. The ASD relay is turned two times by the engine computer. First, it turns on for two seconds when the ignition switch is turned on to insure fuel pressure is up, then it turns off until the computer sees engine rotation, either cranking or running.
This is Chrysler's very effective and reliable system to prevent fires in the event of a crash. If the fuel line is ruptured, there will be no fuel pressure. Without pressure, the injectors won't spray fuel and the engine will stall. The computer will no longer receive pulses from the crankshaft position sensor so it knows the engine stopped, and it turns off the ASD relay. 12 volts is turned off to the fuel pump so no raw fuel is pumped onto the ground.
The most common mistake people make when diagnosing a no-start condition is looking for missing fuel pressure OR missing spark, then troubleshooting that one system. Each of these systems gives very little trouble. You must check for both spark AND fuel. When both are missing, suspect a defective crankshaft position sensor on the rear of the transmission bell housing (3.3L) or in the distributor (3.0L). When replacing it in the 3.3L, the air gap is critical. New ones come with a cardboard spacer glued on to set the gap. It will be sheared off harmlessly when the flywheel turns.
Depending on which engine you have, the firing order is printed on the top of the distributor cap for the 3.0L engine or is controlled by the engine computer on the 3.3L engine. That one fires the three coils in the proper order. Each coil fires two spark plugs at the same time.
Thursday, November 26th, 2009 AT 11:31 PM