Won't start after rain or moisture

Since the forum has linked both the s 10 and the blazer together and suggests posting here for better results, I' repost my s-10 problem here. I have a 88 s10 with 92000 miles. It is a very basic pickup with no frills. It has 2.5 and a distributor and EFI. I live in Utah, a very dry state with very dry air.
The day after it rains, it wont start. I don't even have to drive it the day it rains. If fact, it only has to be a moist night with a lot of dew and cool temps. and I can't start it the next morning. I about run the battery down trying. Usually after 10 minutes of trying I get a few puts from the engine and then after a few more tries, it will start. I have had to pull it a few times to get it started because it just wouldn't start. Once running, it runs great and will start right up every time there after until it sits all night and it is a moist cool night. If it is parked in the garage, it starts every time. Too bad the garage doesn't hold all the vehicles!
What I mean by won't start is the engine turns over just fine but the cylinders won't fire.
I checked the firing of one of the spark plugs and it has no spark or very weak spark at best. I'm thinking that moister is getting into the distributor some how. The oil looks good so I don't think it is coming from the crank case.
Any one shed some light on this problem?

Replace your cap and rotor.


You are getting moisture in the cap, probably cracked. After repeatedly trying to start the truck, you dry it out enough to start.


You could try some dialectical grease in the cap on the contacts. Change the plugs and wires while you are at it.

Right on Laxman21! Replace the Cap and Rotor. Be Doubly damn sure to use an AC Delco Cap and Rotor, Even if you have to wait a day to get one. Other Caps will not last more than a few months in these Trucks, accept nothing else or you'll be sorry. Inspect the old cap when you get it off and you'll find the cracks and/or holes.

I pulled the cap off tonight. It was dirty on the outside but the inside was pristine. The rotor looked good also. it did show a slight discolor on the very end, but nothing that looked like it was burnt or arcing. One thing I did notice is that it seemed to be a slight bit lose. nothing you could tell unless you pushed it from side to side with quite a bit of force, then you could feel the slightest bit of movement. well put a new cap on tommore and see what happens. thanks for any advice.

Thanks for your post Laxman /rick. The Pickup was having a hard time starting today and I stopped trying to start it so I could check for moisture as you indicated. I wanted to find out just what the problem is, so I have decided to change one component at a time. Realizing that just moving the other components might correct a problem inadvertently.
I set out to change out the distributor cap first. In so doing, I rubbed the heater water line directly above it were it comes out of the water jacket of the engine. I felt a little drop of water. Looked at it with a mirror and could tell that a very very very small leak was making it moist in that area, the bottom side of the threads going into the water jacket. It just happens to be directly above the coil wire on the distributor cap. Looking into the coil wire I could see it was corroded and had the slightest bit of moisture on it. A drop must have formed and dripped on it earlier in the night because it defiantly wasn't wet now.
The cap was in great shape. Almost no deposits but a little dirty on the outside. The rotor looked almost new. No sign of wear at all, no deposits, and no sign of arcing.
I have cleaned up the coil wire connection, added boot sealant/lubricant and will work on the heater water hose leak today.
If I still have trouble, I will start replacing all the items you mentioned. (it's going to rain this weekend)!
Thanks for taking the time to point me in the right direction.
RCWeston

If your hard starting problem comes and goes with the rain as you indicated, I don't think you're out of the woods yet. The outside of your cap will be dirty and the inside should be clean. Cracks in the cap can be hard to see. Did you notice any moisture inside of the distributor itself? A water drip from the heater hoses can certainly be a problem, but it should be all the time if the coil wire etc. are corroded, not just when it rains.

I have also had caps that don't seal around the bottom edge that seats on the distributor body. A light coat of grease around the base of the cap will help.

It has been three days now since I worked on the drip and the coil wire. It has been moist every night, but it hasn't rained as the weatherman predicted. It usually doesn't rain here very often.The truck has started right up every morning. I'll have to wait for rain to be satisfied with the results.
I like your idea about sealing the bottom of the cap. I was wondering if it was supposed to have some type of a seal or not.
As soon as it does rains, and I have a chance to get to test it with the same conditions it failed in previously, I will seal the bottom of the cap as you mentioned. If after all this, it seems like the problem is resolved, I think its a good idea to also replace the other old parts.(wires plugs,etc.). sooner or later they will fail also.
thanks for all your help
Rex

I'd say you've solved the issue. I had an idea as to what the issue would be after reading the initial post which turned out to be what you did. Of course I wouldn't be satisfied either until it rains and the humidity gets high enough.

It has been three days now since I worked on the drip and the coil wire. It has been moist every night, but it hasn't rained as the weatherman predicted. It usually doesn't rain here very often.The truck has started right up every morning. I'll have to wait for rain to be satisfied with the results.
I like your idea about sealing the bottom of the cap. I was wondering if it was supposed to have some type of a seal or not.
As soon as it does rains, and I have a chance to get to test it with the same conditions it failed in previously, I will seal the bottom of the cap as you mentioned. If after all this, it seems like the problem is resolved, I think its a good idea to also replace the other old parts.(wires plugs,etc.). sooner or later they will fail also.
thanks for all your help
Rex
No, there is no seal on the cap. Traditionally the cap seats on the base of the distributor, but I've seen old warped caps that will actually rock on the base that not only give you moisture problems, but play hell with your timing.

Has it rained yet?

I still recommend a new AC-Delco Cap and Rotor when you're ready for it. Nothing else will last.

It's has been a couple week now since the repair and it finally rained, three days straight, time to put the repair to a test. It stared right off the bat within 1 or 2 seconds, the first morning after the rain, the next morning it had a 4 or 5 second hesitation, and today it started again with about the same 4 or 5 second hesitation. That's much better than cranking it for up to 10 min as it was before! Time to replace all the old items mentioned with new ones. Your idea to seal the distributor cap sounds good. That is to seal the bottom of the distributor cap with a little grease to keep out any moister if something doesn't fit tightly.
Thanks again everyone. I'm sure an other problem will pop up again with a truck this old. Until then, thanks
Rex

Thanks everyone for you hints and helps. I'm Happy with the starting problem. It seems to start within about 1-2 seconds every morning now. What a difference such a little problem can be!
Rex

Right on Laxman21! Replace the Cap and Rotor. Be Doubly damn sure to use an AC Delco Cap and Rotor, Even if you have to wait a day to get one. Other Caps will not last more than a few months in these Trucks, accept nothing else or you'll be sorry. Inspect the old cap when you get it off and you'll find the cracks and/or holes.
I can't remember which thread here I read but it said don't get an ac delco because for some reason, the way it's designed, sparks can jump to the other plug. Sure enough, that's what it was doing in my truck. You can see the paths on the cap which ones are connected???:screwy: It said to get a napa brand instead. It lasted over 2 years & still no problem. But maybe for an 88 might be different. Just my 2 cents.

Wow you guys are great. I was reading the forum. I have a ford f-250 pickup and it will not start either. If it is moist outside or raining out side or it is a real hot humid day it just would not start. It would not start today and it was damp outside. I took the distributor cap off and the inside of the cap was wet. I wiped it down and it started right up. I will put a litle high temp grease around the bottom of the cap to see if it works for here on out. The garage changed out the distibutor, cap,rotor and they could not even figure it out. Here 500.00 dollars later i figured it out by your post. This thing has been giving me a fit for over a year. This was very frustrating.

Wow you guys are great. I was reading the forum. I have a ford f-250 pickup and it will not start either. If it is moist outside or raining out side or it is a real hot humid day it just would not start. It would not start today and it was damp outside. I took the distributor cap off and the inside of the cap was wet. I wiped it down and it started right up. I will put a litle high temp grease around the bottom of the cap to see if it works for here on out. The garage changed out the distibutor, cap,rotor and they could not even figure it out. Here 500.00 dollars later i figured it out by your post. This thing has been giving me a fit for over a year. This was very frustrating.
Thanks for the reply and remember, even a blind squirrel finds an acorn in the forest once in a while. LOL:smokin: Sometimes we get lucky. Glad to hear your up and running.

I can't remember which thread here I read but it said don't get an ac delco because for some reason, the way it's designed, sparks can jump to the other plug. Sure enough, that's what it was doing in my truck. You can see the paths on the cap which ones are connected???:screwy: It said to get a napa brand instead. It lasted over 2 years & still no problem. But maybe for an 88 might be different. Just my 2 cents.Jalopyjoe, you are the exception rather than the rule for sure. Napa may have a good cap, I don't know, but I can tell you for sure that the Autozone Duralast Gold Cap is pure garbage in these trucks. Mine lasted 6 whole months. Believe it or not, Airtex even makes Distributors and caps. My 2001 Blazer's complete Distributor went bad and was replaced with an Airtex Aftermarket Distributor that came with its own cap. That piece of garbage cap lasted 9 months. My OEM Distributor Cap in my 2000 Jimmy lasted 9 YEARS, while the AC Delco cap that is in it now is like 3 years old. Trust Me when I say to stick with AC Delco Caps, Rotors and Plugs.

^ I agree.

Had a NAPA cap & rotor on my '93 Bravada. It failed in less than a month. Replaced under warranty, it failed in 3 weeks. Bit the bullet, spent the money and bought AC Delco. Lasted 2 years.

Only put AC Delco on my '99 Safari and '02 Astro and never a hint of trouble.

Here is my sad story:

http://www.automotiveforums.com/vbulletin/showthread.php?t=975186

Thanks for the information

It worked