Truck Repair: 1996 4.3 wont start in damp weather, mass airflow sensor, chevy 1500


Question
I have a '96 chevy 1500 4x4. 5 speed 4.3 vortec. Everytime we have a heavy rain or damp conditions it will not start. The next day when it's dry it fires right up. Have changed the distributor cap and fuel filter. Runs pretty good on normal days. Can be running fine when I turn it off and it rains all night and it will not start.  

Answer
Hello David,
I would be pulling some wire harness connectors apart, looking for any sign of moisture, and hosing them down with WD-40, trying the starter after each one to isolate where it is.
Do the conditions need to be damp enough for water to trickle, like flow down the firewall, or just a heavy fog do it?

I might be checking the ignition control module in the distributor.
The mass airflow sensor in the air snorkle is a possibility, although I wouldn't think it would keep it from starting. Read this link. Ford, I know, but some good reading, even if it isn't your problem.
http://www.fordscorpio.co.uk/cleanmaf.htm

Van

Van