Extensive tests all check out. Still won't start reliably.

I have a 350 in a '78 chevy 1Ton.
- New Coil (tests good)
- New Cap (test good from ground to center button)
- New Rotor
- Ignition Modual (test good / ran 15 tests in 3 days, poor AutoZone guys)
- New Plug Wires (good ones)
- New Botch Platinum Plugs
- Pickup Coil in Distributor (tests good)
- Power to Coil - key on - 14v
- Power to Coil - key in start possition - 12v

Everything tests awsome! Here's the deal. I will go outside to start it for work and sometimes it fires like a champ, and sometimes no spark. It runs great, sounds great, and has plenty of power. I have checked, checked, and rechecked every. I went outside last night to go out. No spark. So I removed the cap and sprays everything evectrical to evaporate any moisture, waited for it to dry a few mins, and still woul'nt start. I had decided to start it this morning and if it did not start I would remove the ignition modual from inside the distributor and then warm it up inside the house with a space heater, then reinstall it and try that. Only prob is it fired right up this morning! Hahahaha!! The rason I was gunna try this trick was that I thought about how it was cold when I tried to start it every time and when I brought the module in to be tested it was in the van on floor under the heater... That does not help my cause I know this. But this morning the temp was 40f outside and it still fired.. also moisture in air and slight rainny/mist. Last night I am not too sure what the temp was.

If anyone has anything to comment that may help, I would appreciate it very much. Thanks all!

-Joe

The first thing is to dump the Bosh plugs and go with AC/Delco
It sounds like you are loosing the dist ground. Check all the grounds on the engine block. Make sure they are clean and tight.
Also check the wiring for the dist for any nicks or cracks or breaks in the wiring. I would also get a complete new dist and see if that helps and if it does not help then you know the problem is in the wiring going to the dist.

Thanx.. I actually broke down on the side of the raod just before your reply.. I got a bit angry and took out the distributor on the side of the road, got a new one, and replaced it.. No probs since.. Weird thing is I can't think of what the prob was? the plugs, plug wires, coil, cap/rotor, ignition modual were all replaced and tested fine before hand.. and I tested the pickup coil in the dist and all was fine... so why would a new distributor work fer me? hahaha... anyways the new distributor came with a new coil and ignition modual so now I have the new ones I bought prior to the dist sitting in my glove box.. thanx fer your reply and help!

-Goce

Well if it does happen again, I would check your grounds and all wiring to the distributor like fireplug suggested. Not bad advise considering its a '78 and all.

From my experience recently a picpup coil can test good but still not be good. That was my problem.

I do not trust any of those tests for the module or pick up coils because they do not reporduce real world condictions with heat and vibrations. I have see both modules and pick up coils pass these type of tests when I know that they are bad.

interesting, and I can kinda understand why this is so. Learn somethin' everyday...