wont run when it rains on 2000 GMC Safari

I got a rebult engine in my van and Every time it rains it won't run so i had the distribiter cap changed and new sparkplug and wires now my battery is dead. I have been told that it could be a fuil pump but I here it go on and off

Asked by for the 2000 GMC Safari
First you have to determine what the issue is when the car won't run. You need to check for fuel and spark. Once it's determined which one is the issue then you need to diagnose that system to find out why it's not working.
1 more answer
Trin the intake spraying some starting ether into the intake, if it starts the problem is ignition.