I have a 98 Ram Van with a 5.9 L and any time it rains over night or thick fog in the morning the van won't start. If runinng in the day and it starts raining it's ok and continues drive well. It has somthing to do with the van being cold and damp. I change out the Dist. Cap and Rotor yesterday and it ran fine. It had rain overnight and now it won't start today. Do they have probelms with the coils? I had changed it a couple of years ago I shouldn't have to do it again do I? It seems to me like a secondary grounding problem, No I did not pull a plug to see, (a little hard for me to get to), just need to know if its the coil again or something else, I can see that the coil wire to the cap and that is ok and not grounding out. any help , ideas?

 

Cap and rotor are a good start, but the S.P. wires are most likely your culprit IMO.

Try removing each wire one at a time spraying it with wd 40 and cleaning it off good and re attach making sure no wires touch each other or the valve covers or other grounded metal.

I'd just replace the wires.
Or if you've got a strong heart, ground yourself and grab a couple wires while cranking the engine. That should narrow it downhttps://dodgeforum.com/forum/images/icons/icon10.gif

 

I installed new wires today, and it still wont start. I get spark to the plugs, but the spark comming off the coil is yellow, (I always thought it should be blue-green).
Re-cap;
I have new cap, rotor, plugs and wires-
I get spark to the plugs-
It runs fine when dry-
I double check and made sure the firing order was right,
I put a new fuel pump on 6 mo. ago and I hear it come on when the key is turned.
still it wont start.

 

Yes it should be blue, yellow is a sign of weak spark. You're probably looking at needing a new coil. It's not unusual to have to replace them every couple of years in these vans. Personally, I think their quick failure is a result of their location on the engine. It's very susceptible to getting wet down there.

 

In the mean time someone told me to Check/change out the PCM,
is that something I neeed to check into?
does anyone know where it's located on this van?
some have it in the distributor below the rotor plate,
I'm not sure where it's at on this van.

 

That's the camshaft position sensor (pickup coil) below the rotor. The PCM is under the hood mounted to the firewall right above the engine. It has 3 large plugs going to it. Since you are getting spark, it's likely that the PCM is still good.

Coil $30, PCM $300, take your pick.

 

The new coil and wires did the trick, now just have to wait till it rains to see if it still works.
Thanks to everyone.

 

If you don't want to wait, you could lightly spray the engine with a hose.