Plymouth Repair: cranks but wont start, crankshaft position sensor, crank sensor

Question
QUESTION: 1997 plymouth voyager standard van, 2.4L eng., 237000 miles. Cranks but won't start. Was starting and running fine just before this. Fuel flow is good, pump working and plenty of gas at the rail. Battery check is good. Air flow and all vac lines appear okay. Plug wires are fine, about 25k on them. Plugs are new. I've determined that there's no spark at the plugs. Handheld OBD II shows "pass" with no error codes displayed. An ohm check of coilpac is right where the numbers should be on both primary and secondary tests. Cam position sensor is new (had displayed an error code on OBD) and was working fine for about 200 miles prior to this. Out of ideas, driving me nuts. Any help would be greatly appreciated.

ANSWER: Usually when we have a no start/no spark one of the first suspects is a failed crankshaft position sensor. When these fail they tend not to leave any codes, the reason being that the PCM uses the sensors RPM to know if the car is running. If it does not see a valid RPM signal it assumes the engine is not running and takes no action as far as generating a code for the crank sensor. What it may do is throw a code for cam/crank out of sync or something similar which are generic codes depending on the scanner used. Your best course of action at this point would be to replace the crank position sensor.

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QUESTION: First, thanks so much for taking the time to respond promptly and so thoroughly. I have been out of town (work) shortly after you answered and so have been delayed getting back to you. Crank sensor has been replaced and I installed a new coilpack just to be sure even though the original tested good. The problem persists, no spark. I'm wondering if PCM/ECM could be bad even though there's no dash service light on and OBD does not show an error code. More frustrated then ever. Thanks again. I will be giving you an excellent rating regardless of this problem's outcome.

Answer
The only reliable way to diagnose your problem would be to take your car to a reputable repair shop for a proper diagnostic. OBD readers are OK for reading codes but can't display the data needed to see what's going on with the controller. I could forward the test procedures for testing the cam and crank sensors. But since it's only an assumption that the problem is with those sensors, I would hesitate to do so. The reason being that the engine control system is fairly complex and needs an experienced technician to identify and correct any problems. Jumping to any conclusions that it may be this part or that part that has failed can lead to a lot of wasted time and money. Use both to have the car properly diagnosed.