2003 b2500 5.2L no start when wet/damp
 

hey there. i have a beater of a van that has trouble starting if i leave it sitting in rain or damp/wet conditions. if i am running it consistently throughout the wet period, it starts and runs fine. if i leave it sitting until the engine gets cold, it will start rather hard but will always start. i can smell fuel as its trying to start and it cranks and cranks and sputters, just on the verge of running. i have put all new plugs wires cap rotor coil and battery in it. im leaning towards the idea that it may be something to do with the intake sensors or something related to air. assuming that it gets fuel, and certain that there is spark, i can only conclude that it is not getting enough air or something is preventing it. once i crank it to the point of almost killing the battery and then waiting for 10-20mins and cranking again it will start only due to the brand new battery. once i get it running it runs strong and without any issue.

the van has 211k kilometers on it (i am in canada and the van was built in canada)

any insight would be so appreciated. i love my piece of **** van it is a beast and i love to keep it running. this thing owes me nothing!

take care.

Cleaning the throttle body would be a good start if it hasn't been done anytime recently that you can recall. Best to take it completely off and remove the other sensors before cleaning ( throttle position sensor is on driverside of TB and MAP sensor attached to front) pay special attention to the IAC located on the rear side of the throttle body, take it off and carefully clean it, (avoiding twisting or moving the plunger) as well as the orifice it mounts in. You'll be looking for carbon build up and an over all dirty looking iac and throttle body (inside under and topside) . Old tooth brush, rags, maybe q-tips with TB or brake cleaner should help.
Disconnect the battery before hand, then when reinstalled with new TB gasket, reconnect battery, turn key to on but don't start, wait 10-20 seconds, then fire it up

Check em out... There are some good threads you can find regarding cleaning the throttle body and IAC worth reading if you use the search box up top, good luck and check back in here

Is the ignition coil original?

your vans hood is probably leaking water onto the dist cap and coil wires

Had a 2000 ram van 2500 that had the same issue. My issue was the coil was weak. It showed spark with a test light but wasn't enough to fire.