Chevy & GMC Vans

hello again everyone;
I have been having a starting problem. When I drive the van on warm to cool days (30 degrees to sub-zero temps) and park it in the driveway, it sits all night then will crank but not start.
I take it into the garage (push it in) warm it up with torpedo heater, and dry the front out and it starts again beautifully.
I have found that if the van gets wet and I park it in an unheated garage it starts great every time, just NOT when I leave it outside overnight.
I have checked all the wiring behind the battery under the hood, and can find NO wires showing and nothing to indicate what might be getting too cold, or wet to cause this to happen.
Also, there are still no codes showing up to point to a specific problem.
Any ideas would help alot.
thanks

what year van?

I has a similar problem but wasn't tempature related . Mine just every once in a while would roll over but not start and do it just when you didn't want it too. ( getting gas at a busy station etc.) Anyhow , FINALLY I found the problem maybe you should look at. Right behind the battery , wires go threw the firewall to inside the van. I'm sure one of those wires powered the computer or something as when I fixed to burned one it never did it again. That van was a 94 Safari. I hope this helps as it was a really "out there" problem that took me some time to diagnos.

I see now that you checked those wires but something else I noticed on mine was that when it happened , when you left the key switch to run the DRL's didn't work and also the radio if I remember correctl.

Could be condensation causing moisture in the distributor cap, preventing you from getting a good spark.

I just had the same problem. Turned out to be a failing ignition coil.

I've also seen a coil cause this.

Even an unheated garage can make a difference in how a vehicle acts. I'm not sure why, but I bet heat retention has something to do with it. Just a guess, though.

I agree with the Squidster. Sounds like the coil may be in the fail mode.

I say ditto on the coil. It might not be that, but you have not given us much to go on. What year van? When was the last time the cap, rotor, wires and plugs were done? Does it crank well?

had both issues, condensation in the distributor cap and a failing coil...at different times.

Sorry for the lack of info gentlemen; the van is a 98', I have a code reader that comes up clean for everything except a slipping tranny once in a while. I removed the coil and tested it, good to go; Also removed the distributor and had ALL within tested, came back golden.
There was water running down the outer firewall behind the battery and I put a piece of rubber between the lower windsheild cover and across the battery and it seemed to help, have only left it outside a few days so far and it hasn't been too cold yet, so I'll wait and see.
Just trying to find out if onyone else had the same problem and what caused it, so I can nip it quick.

I have had a similar problem. One time it was the plugs/cap/rotor. The other time was the coil and wires (should have changed them when I did the cap/rotor/plugs but they looked good)

Check your fuel pressure as it could be a flaky fuel pump on its way out, although I doubt it.

How long has it been since the last tune-up?

Was the coil tested at the same temp as when there was a problem? My point being that bench testing wont always give you good results.