Rats. That's an interference engine. The valves will be bent if they're hit by the pistons. Try looking through the oil fill cap to see if the camshaft is turning when a helper cranks the engine. If it's not, the timing belt is broken. If it is, the belt may have just jumped a tooth or two and no valves are damaged yet.
Check for diagnostic fault codes too. Chrysler makes doing that yourself real easy. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers show up in the odometer display. If we get a code for no signal from the camshaft position sensor, suspect the broken timing belt. If the belt has just jumped one or two teeth, the code will be "cam and crank sync" meaning the two signals are arriving at different times. When the belt jumps one tooth while you're driving, that is the code that will set. At two teeth, the Engine Computer will shut the engine down to protect the valves. At three teeth, (or when the belt breaks), is when the valves get bent.
When signals arrive from the cam and crank sensors, the Engine Computer turns on the automatic shutdown (ASD) relay which sends power to the ignition coils, injectors, and fuel pump relay. If the timing belt broke just as you started the engine, the camshaft position sensor's signals would stop arriving and the computer would turn off the ASD relay. That would remove power to the ignition coils just as if the computer were switching them off like normal. All six coils would produce one last spark, and you know for sure five of them would be at the wrong time. That could explain the backfire.
Saturday, September 21st, 2013 AT 2:33 AM