2003 sliverado 4.3 does not start after rain

[John Peleponuk]

I have a 2003 silverado wt 2wd that runs well in dry weather but will not start in the rain.  

 

After it has been outside in the rain for a few days the truck will crank but will not start.  After a dry day or so the truck will start up.  The last time it rained I left it outside to confirm.  The truck did not start after a day of moderate and consistent rain.  The hood is secure and nothing seems to be wet in the engine compartment. Plugs, wires, cap are all new.  the air filter is clean.  The truck has evap codes but this is typical for my truck and this problem seems separate.  I get no codes regarding starting / misfire / sensor issue.  After the weather turned drier and a day of sun the truck did start, but very roughly / sputtering.  That was only on startup the first time and after just a few seconds it was running smoothly and started again during all dry weather starts.

 

Any advice would be appreciated.

[Jsdirt]

When it won't start, you'll need to find what you're missing and go from there. Spark, fuel, or both. Once you find out what is missing, you can troubleshoot from there.

 

More than likely there's either a failing cube relay in the underhood fuse box, a corroded fuse or one that has bad pin contact / continuity, a failing module, or damaged wiring. 

[Brian R.]

Did you ever figure it out? Because I am having this exact issue. Everything you described. Same year same engine. I would love to know what you found.