dr76,

After looking through what you've written, can you provide some background info regarding the timing belt change? What, if any, symptoms were you having before the belt change? Did you have any codes/check engine light before the belt change? After you changed the belt and had it running (with the original ICM), exactly what was happening? Ran fine cold, rough hot starts? Codes?

As for checking the crank sensor, let me do some digging, as I believe there's some simple checks you can do to get about 90% certainty of a good/bad crank sensor. I believe it's as simple as disconnecting the wiring to the sensor, applying +12V (via alligator clips) to one terminal of the sensor, and reading the other terminal with a voltmeter. Then, you rotate the crank with a breaker bar, looking for movement of the voltmeter reading. (After all, this is what's essentially happening when your truck's running, just at a high rate of speed.) I just need to verify the type of sensor you have and the electrical connections to it. (I believe your sensor may have three wires, due to the information below (crank sensor is both PIP and CID).

In any event, here's some info for the 94 2.3L Rangers. I don't think there is a difference between 93 and 94, but I'm not positive.

"The crankshaft position sensor (CKP sensor) is a dual Hall effect magnetic switch, which is actuated by the dual vane armature on the crankshaft pulley hub. The crankshaft position sensor generates two separate signals, PIP (profile ignition pick-up) and CID (cylinder identification). The PIP signal provides base timing and rpm information, while the CID signal is used to synchronize the ignition coils . Initial timing (base timing) is set at 10 ± 2 degrees BTDC and is not adjustable.

The main function of the ignition control module is to switch between ignition coils and trigger the ignition coils to spark. The ignition control module receives the PIP and CID signals from the crankshaft position sensor, and the SPOUT (spark output) signal from the powertrain control module . During normal operation, PIP is passed on to the powertrain control module and provides base timing and rpm information. The CID signal provides the ignition control module (ICM) with the information required to switch between the ignition coils for cylinders 1 and 4 and the ignition coils for cylinders 2 and 3. The SPOUT (spark output) signal (from the powertrain control module) contains the optimum spark timing and dwell time information. The spark angle is determined by the rising edge of the SPOUT signal because that is when coil current "turns off" and spark occurs. The dwell time is controlled or varied by varying the duty cycle (duration) of the SPOUT signal. Current flows in an ignition coil (dwell) when SPOUT is "low". This feature is called CCD (computer controlled dwell). Therefore, with the proper inputs of PIP, CID and SPOUT the ignition control module turns the ignition coils on and off in the proper sequence for spark control.

During some faults of the ignition control module, the Failure Mode Effects Management (FMEM) portion of the ignition control module will maintain vehicle operation. If the ignition control module does not receive the SPOUT input, it will automatically turn the ignition coils on and off using the PIP signal. However, this will result in fixed spark timing (ten degrees BTDC) and a fixed dwell time (no CCD). If the ignition control module does not receive the CID input, random coil synchronization will be attempted by the ignition control module. Therefore, several start attempts may be required to start the engine.

The Ignition Diagnostic Monitor (IDM) is a function of the ignition control module. The ignition control module sends information on system failures to the powertrain control module which stores the information for diagnostic self test. The IDM signal also is used to drive the test tachometer for system diagnosis."

As an aside... I believe the IDM and SPOUT are supposed to be virtually mirror images of one another. They're square-wave signals between the ICM and PCM.