won't start when it rains

[rdburnssr]

1998 Blazer(4.6) tuned up about 30,000 miles ago. Runs fine but won't start when it rains. Cranks right up on a dry day even when it cold. Just turns over when it's wet

[MT-2500]

Originally Posted by rdburnssr

1998 Blazer(4.6) tuned up about 30,000 miles ago. Runs fine but won't start when it rains. Cranks right up on a dry day even when it cold. Just turns over when it's wet

4.3 v6?
Does engine crank over good?
Have you checked dist cap and rotor for moisture /cracks and plug wires and side of coil for shorting out?

Good wires and AC delco plugs?

[Rick Norwood]

Originally Posted by MT-2500

4.3 v6?
Does engine crank over good?
Have you checked dist cap and rotor for moisture /cracks and plug wires and side of coil for shorting out?

Good wires and AC delco plugs?

Right on as always MT. This sounds like a wet distributor (cap) and possibly bad wires. When was your last full tune up? What did you replace 30,000 miles ago?

Try starting at night with no lights and look under the hood for blue arcing on the plug and coil wires. Remove your distributor cap and look for moisture, cracks, holes etc. If you find anything bad, replace with AC-Delco parts only. Anything else is wasting money.

[mixin]

I had a similar prob with my 1997 blazer where it would start fine, but would have a random misfire when accelerating when the roads were wet. This misfire would clear up after driving for about 20 min. There is a common problem with these distributors with getting moisture inside - possibly due to plugged vents in the base. The moisture would cook itself out if I drove long enough though.

So, I pulled the cap and rotor, soaked the distributor with carb cleaner for about five min and then blasted it (especially all the nooks and crannies in the base) with compressed air until dry. I replaced the cap and rotor with new and gave them a lite coat of WD-40 before reassembly. I have not had this problem since and I do this cleaning and reassembly procedure every time I do a tune up - usually every 30-40K is my personal preference.

Hope this helps!

[Schrade]

Originally Posted by rdburnssr

Runs fine but won't start when it rains.