1993 Plymouth Colt 4 cyl All Wheel Drive Automatic
Sudden complete failure to start after sitting overnight. First time symptom. Engine cranks fine. Ignition strobe shows no spark. Replacement distributor on order. (2.4 L engine). Coil looked OK with meter, but a test of the power transistor in the distributor may indicate failure. I have downloaded electrical schematics for the ignition system, and the base of this power transistor is fed from the engine control module. A shunt transistor in the engine control module can disable this power transistor.
My question is: If sensor inputs to the engine control module are not correct or have failed, will the ECM actively disable the distributor? Or does the ECM just allow the distributor to fire when the ignition key is turned on? Also, is it possible to bypass the ECM and enable the distributor directly? We are concerned that the the actual problem may be upstream of the distributor, and we may need to do additional troubleshooting.