Chrysler Repair: 95 LHS wont start, crank shaft position sensor, chrysler lhs

Question
Hi Roland,
It's me again (95 Chrysler LHS won't start, partial spark only) I have verified that I have 8 volts to the cam and crank position sensors. Actually, it measures 8.97 volts. I
also checked continuity in the returning signal wires and they checked okay. I cranked the engine over by hand and measured 4.97 volt pulses at pins #24 and #44 at the PCM. I
rechecked the pulses at the coil pack and it was the same result. The black wire would become grounded (no pulses), the white wire would pulse three times with a short pause and then repeat the sequence, and the red wire was dead.

Just a little history on this vehicle, before my daughter bought this car, a year ago the PCM failed and was replaced. It ran fine for a year until this fall. It started running just a little rough and then a few days later on a rainy, cold morning, it wouldn't start. I
replaced the spark plugs (they weren't bad, normal wear) and the crank shaft position sensor. I did a quick check on the cam position sensor and it tested okay. I checked the pulses at the coil pack and saw that there was a problem. After checking the wiring and connections, I bought a PCM from a junk yard and it reacted the same way. I replaced the coil pack thinking that just maybe there was something wrong with it causing the PCM to react this way. Nope, it
was good. Then out of desperation, I replaced the cam position sensor. Nope, no change. Since I wasn't sure if the junk yard PCM was good when I bought it, I bought a remanufactured one from a parts store and now it is doing the same thing. Being stumped, I wrote to you. I have
now rechecked everything and the problem still seems to be the PCM. Am I missing something? Is it possible to have a feedback voltage from another source causing the PCM to react this way? Or maybe a failed sensor somewhere creating a weird internal condition in the PCM? I have solved many severe vehicle problems before, but this one really has me stumped. I have a complete wiring diagram of the car, but I sure could use a PCM schematic.

Also, I am performing most of these checks with the fuel pump relay removed. My daughter already had the engine flooded from trying to start it and as I started checking things out, the flooding worsened. I checked the wiring diagram to make sure that disconnecting the relay would not disable the PCM.

Answer
Hi Bill,
Without a code this is a conundrum.
I have the '93/4 troubleshooting manual for the 3.3/3.5 and about the only non-sensor test is a check of the PCM grounds and power supply.
Specifically: remove the plug at the PCM and verify:
cavity 5, 11, and 12 should all be grounded. Then check cavity 9 with the ignition switch on and make sure you get over 10 volts.
Because you get no codes on a self-readout, and if we assume that you might get a "no response" indication if you tried with a diagnostic readout box, there are 18 pages of tests that are comprehensive for that situation. It would cost me about $2 to xerox copy and mail you those pages. So let me know if you want them and I'll get them to you. You can send me back 5-39 cent stamps in return.
Roland