Me too Kerry, I ll open that beer and wish ya luck..

Well, another long afternoon and no success.....changed out the ICM and Coil with new GM Delco..... but still have the same "Crank no start" problem.  From the look of the old coil and ICM, they were original and needed replacing.  The coil was rusted and the ICM heat sink silicon gel was all dried up to a powder.

Anyways....following the SM diagnostics, the ICM connector has 12 volts in on two wires, solid ground on the third and the fourth wire has good continuity to the PCM. 
Did the same checks on the Opti connector and everything is what the SM indicates. 
Also pulled the ignition coil wire and inspected -- it was new last year and still looks new....also tests out with 5300 ohms. 
Also did the SM test to jump the two "B" wires for the coil and test the "A" with the test light while cranking the engine.....this is suppose to cause the test light to flash, but NO FLASH....so guess what, the SM says either the ICM is bad or the ICM connector is bad -- no way all their tests said everything was good......HMMMMMMMMMMMM

Also cranked the engine and did Stingray Jims wire jiggle dance......no start.

Also rechecked every fuse with the DVM (just in case I had a sneaky non-visible break)....they all tested good

Here is the last thought.......the ONLY thing I did after the last start (Yah, I know, I just remembered it today as I was thinking through all the possible causes) was I got a keyless entry fob from Corvettes of Dallas.  (it was free as they did not have a working one when my son bought the car).  anyways, we tested it at the dealer and it programmed their 95.  When I tried to program my 95, I could not get the computer to enter into programming mode (light on the diagnostic center never came on).  I tried it several times but gave up thinking it needed the power door lock connectors plugged in (have all the door panels off to redo the weather stripping).

So my question is, could I have somehow disabled the start programming because I could not get into the keyless entry program???? I am grasping for anything now.

Tux, tomorrow I plan to connect the power door locks (power windows and rear hatch were always connected because I needed those) JUST TO SEE WHAT HAPPENS......NO WAY it should matter because I was driving it before with the door panels and power locks disconnectd.....but hey...its a vette with an attitude.

TUX....GET BUBBA OUT OF HERE.....I found his after market security under my dash also a few months ago.   A key in a cylinder with two wires going somewhere.  anyways, the car worked with it but who knows now.

Thanks everyone for your continued suggestions  (and no, I am not frustrated enough to pull the Opti or replace the PCM .... yet)
Reds82CE2008-08-31 16:57:16

Uh oh....you may have a CCM that took a doo-doo.
I just thought of that, since you mentioned the key thing. The Central Control Module, if bad, WILL give you a no start, AND, it will not let you program the key/fob for the security system. But then...it would also keep it from cranking, too...
You may have disabled the starting thingy when you attempted the re-program for the key...might as well go ahead and plug all that crap back in, and give it another shot.
I had a '96 at the shop that had pretty much the same issue, and testing on it showed the CCM was shot. We got a new CCM and installed it, but STILL had to send it to the dealer to get the danged key programed.
Hopefully yours is not like that...

Would a bad battery in the key fob do this??

Kerry, your skeerin me... I had tried to put this C4 episode outta me lil pea brain an now it's s-l-o-w-l-y coming back (OUCH).

Okay did your car every so often happen to lock itself? That is the one thing I fergot to mention. All of your symptoms are the same as whut mine were (cept that one).

I also borrowed a friend keyfob to program the car to see if it was gonna werk prior to buying a keyfob. Primarily because I I was struggling with the "other" electrical issues simultaneously. Like yours it wouldn't work. That is how I found the severed harness. I couldn't figure out why is wasn't working until I removed the door panel and said " Oh my God..... ain't that just grand!"

I can tell you that in 94 they made the harness specific for that car. Finding a used one was impossible so I painstakingly repaired the old one 1st rather than donating $150.00 to the stealership to see if it worked. Fortunite for me it worked fine afterwards.

I believe that you will be able to locate a used harness coil for your car with success if you find that yours happens to be damaged as well. I might note here that I had no window problems (up / down) to indicate something had gone wrong. It did appear though that the root cause of the harness coil having been severed was it had came loose and manage to slide over into the tract.

Candle still burning Bro......

If I remember right, when programing the key/fob, it will cycle the door locks, so ya might need all the stuff connected.
Does your key have the little resistor pellet in it?

Yes, the key has the pellet, but both sets of keys give the same "Crank-no-start".

Reconnected all the door electrical connections....still no change.

So, I checked all the codes in the computers again, CCM 1.2, 1.3, 1.4.  all these settings are normal and indicate the CCM is communicating to all the sensors correctly.  In 1.3 mode, I could see the CCM turning on/off sensors/lights.  So this tells me the CCM GROUNDS ARE GOOD.  Also verified again there are no stored DTC codes in the PCM/ECM/ABS/TCS/DERM. 

Back to looking for bad connectors by doing a continuity test on all the wires....someone tell me there is an easier way
Reds82CE2008-09-01 14:18:04

All my grounds from the PCM are good.  Pulled the PCM connectors off, connected the test light to each ground pin and light came on.

Also did a continuity test on the Opti 4 wire connector back to the PCM:
B2 - Low Resolution Signal Input was 3.4 ohms
B3 - Distributor Reference Low Signal was 2.0 ohms
B14 - Distributor Ignition Feed was 0.6 ohms
B20 - High Resolution Signal Input was 0.8 ohms

I can't find anywhere in the SM that tells me if B2 and B3 should be that high....ANYONE KNOW????

According to the SM, I still need to test the following which causes a crank no start:
B2 - Low Resolution Signal (but this should set DTC 16)
B3 - Distributor Reference low signal (No DTC set)
B5 - Ignition Control (should set DTC 41 or 42 and I installed a new coil an d ICM so can rule this one out)
B14 - Distributor Feed (No DTC set)
B15 - PCM Battery Feed (No DTC set and has something to do with the Oil pressure switch)
B30 - PCM Ignition Feed (No DTC set)

The  test for B2 is "TEST CONNECTOR 'A' DISTRIBUTOR 'A' " and B3 uses "D"..............IS THIS JUST A CONTINUITY TEST??? Same as I did above?

B2 & B3 appear to have high resistance. As far as I know, they should read the same as the other two wires, UNLESS there is a "filter" in-line on them. I don't have diagrams here for the '95, but I can get what I have at the shop tomorrow...

 As the owner of an Lt4 with 50k and starting ton leave a small Puddle of Antifreeze I have been fowwoling this one with great Interest. The big Waterpump-Optispark-Plugwire Replacement is just around the corner. All the advice given above is way above my Head so all I can do is agree as it all makes sence to me. The only thing I can add is to give Gordon Killebrew a Call I assume If you guys know as much as you do you know who He is. For those here that don't He Teach's Troubleshooting Class for C4's. He is the Guy who rewrote the Shop Manuels for GM. If a 95 won't fire cause the left Rear Tire is low and the passenger Seatbelt is undone wile the Hood is open He is the Guy who will know. www.gordonkillebrew.com