You replaced the Engine Computer. That means the 12 volt memory circuit was bad. That is why there are no fault codes. Removing the computer or disconnecting the battery erases the codes, then that valuable information is lost. Resetting fault codes has nothing to do with a drive cycle, although some defects are only detected under certain driving conditions. That can include codes related to the crankshaft position sensor and camshaft position sensor. Often the missing signal from one of those is only detected while the stalling engine is coasting to a stop. Those codes may not set by simply cranking the engine. You need a scanner to view live data to see if those signals are arriving at the Engine Computer. I have a Chrysler DRB3 scanner for all of my vehicles. That lists each sensor with a "No" or "Present" during cranking. Codes for electrical problems, like cut or grounded wires, and some sensor failures, will be detected the instant you turn on the ignition switch, and the fault codes will set at that time. Do you know how to read the codes yourself without a scanner?
You can verify if one of those sensor signals is missing without a scanner. Use a test light to check for the 12 volts. Most digital voltmeters do not respond fast enough for this test. Back-probe through the electrical connector for either coil pack, any injector, or either of the two smaller terminals on the back of the alternator. The correct wire is the one that is the same color at the coils and every injector. Typically that is the dark green/orange wire. You will see the test light turn on for one second when you turn on the ignition switch. What is important is if it turns on again during cranking.
If you do not get 12 volts during cranking, you will not have spark, injector pulses, or fuel pump.
Thursday, October 4th, 2018 AT 10:32 AM