97 Astrovan won't start after rainy spell

I’ve had this problem intermittently for 7 years of owning this vehicle. Just did it again this weekend, after 5 days of continuous rain. The van was parked in the carport the whole time. When I tried to start it, the engine tried to catch and chugged a bit after releasing the key. Wouldn’t start. I opened the hood and let it sit for a day, whereupon it started right up, with the “servive engine soon” light on. Drove to town, the light went out when I started it to come home.

The question is what makes it misfire under damp conditions? Any thoughts?


Old, dried-out spark plug wires often cause starting difficulties in damp weather.

If the insulation on the wires is cracked the electricity will short directly to the engine block. You can see it at night. It looks like tiny bolts of lightning.

Something comes to mind when you say this has been a on going problem. I remember a GM “campaign” to simply relocate the coil wire on the distributor cap (if you had long arms it took about 30 seconds,otherwise you had to pull the engine cover).

Get that cover off and see if anything looks out of place.

It sounds like you are dealing with what mechanics call a “crank no-start” rather than a misfire. I would take a look at crankshaft position sensor and perhaps a oil pressure sender that inhibits spark. None of my ideas really fit a problem with a “raining but not in the rain” situation.

I’ll try the plug wires, pretty sure they’ve never been replaced. I have seen that “lightning” before (on my 95 Buick Century)- it caused rough running rather than not starting. Of course, you can’t even see the plug wires on the van without pulling the cover.

Some history:

All the electrical components, sensors etc were replaced right after I bought this vehicle. That was the first time it wouldn’t start, and that was in dry West Tx. I had another mysterious episode later where the ECM-B fuse kept blowing, dealership found a wire shorting to the engine and taped it up. This summer I got another new coil and ignition module after it quit while driving on the Interstate at night. I’m on the third fuel pump, of course it doesn’t start when they go out, lol. Other repairs done that have nothing to do with this- water pump and radiator replaced, air conditioning system fixed, bearings and seal in the rear end, both window switches, wiper motor, catalytic converter.

I change the oil and filters regularly, and use fuel system cleaner.

Back to what shorts out after being subjected to 100% humidity for several days- are there any other likely suspects?

That AC repair could be related as componets like compressor and AC plumbing are close to distributor,perhaps something got knocked sideways.

Well, I haven’t done anything you suggested, and today (2 months later) it won’t start again. Has been damp and cold here for a couple of weeks, and the van’s been parked. I did talk with a dealership mechanic, and he said it’s likely the cap and rotor causing the problem.

The sun just came out, so I guess it will start again in a couple of hours. If not, I’ll go buy some parts and pull the doghouse off.