[ADDvanced]

Just got back from a 4000 mile road trip from Wisconsin to Arizona and back, van worked flawlessly. Got back to Wisconsin, it started slushing/snowing/raining, SUPER high humidity..... day later, cranks, won't start. And like the previous times, I'll probably have to either:

1. Wait a few days for it to be less humid and it will suddenly work again without any issues
2. Pull the whole fucking doghouse off, and replace the cap and rotor.

I have replaced the cap and rotor TWICE in the past 3 years, due to corrosion. What the hell is with this? I get MAYBE 5000 miles out of a cap and rotor, and I only use AC Delco parts. This is driving me effing crazy. I am fully prepared to purchase a billet expensive *** distributor to avoid having to do this again, but I'm not sure that's what the problem is.

My van has 116k miles btw, so if you're thinking the distributor gear is extremely worn, kind of doubt that given that it's low mileage. Plus, that doesn't explain why a new cap/rotor fix this shit. Ideas?

Edit: removed swears. I am angry.

 

[AstroWill]

My van has 116k miles btw, so if you're thinking the distributor gear is extremely worn, kind of doubt that given that it's low mileage.

So right around the mileage where they start to have issues? Have you read this and the distributor page? Astro-Safari-Info - Pancake Distributor Disease

 

[ADDvanced]

Thanks Will! I read something about this over a year ago but could not find it. Going to be reading up now. So sick of this.

Edit: Okay, last time I did this, I did check for play in the rotor, and it seemed like the second (good) video on your page. That said, I did notice some hesitation on partial throttle, occasionally. Honestly I'm fed up with this distributor in general and want to replace the whole thing with a higher quality unit. Going to start hunting.

 

[MechBob]

Well, usually I have found it is moisture in a low voltage circuit(pcm) causing no start, BUT-
if you are pretty sure it is moisture inside the cap, as you see the moisture, then you should do what has been done for many years, remove the screens in the vents in the distributor. This allows the moisture to escape much faster. Some say to just clean the screens, but, many years ago, we had a GM bulletin that said to just remove them, which we did.Happened only once to me,years ago, in a V8,that crusty buildup on the contacts collects and blocks the screen(s), and the old V8's had a big vent. Also, some aftermarket aluminum distrib's for the 4.3 have usually, no screens, just holes, but are tiny, they should be drilled out, if you live in a area, or your driving conditions give you this repeated "moisture" in the cap issue. For those that never seen these, here is a vid, I didn't really listen to what he says(clean or remove) just wanted to find something to post and show people. May foreign cars, for many years, had/have vents built in the top of the cap, many hi-po people drill holes in the caps, although for them, this is more to remove ionized gasses. Anyway, remove those screens, a quick easy test. People swear caps last way longer,also, way less corrosion.

 

[ADDvanced]

Anyone have a part # for a cap and rotor that have brass terminals? Going to replace the whole distributor and put brass cap/rotor on it....

 

[ADDvanced]

New distributor ordered, and brass cap/rotor as well. Should be here monday. can't wait! Thanks again for the link, Will!

 

[WoodButcher]

I did this dance for years w/ my '97. Replaced the dizzy w/ Skip White twice. Started buying buying the lifetime parts, cap and rotor from autozone or advance auto. I'd keep a spare in the van and at the first hint of trouble swap it out and get another.

 

[ADDvanced]

Should I be drilling a hole in the cap as well, to help moisture vent out the top? Making the holes bigger in the bottom makes sense, I'm just thinking of water vapor going upwrads, then collecting inside the cap.

 

[AstroWill]

Should I be drilling a hole in the cap as well, to help moisture vent out the top? Making the holes bigger in the bottom makes sense, I'm just thinking of water vapor going upwrads, then collecting inside the cap.

No, definitely don't drill a hole in the cap. Pretty sure they had fixed the holes in the distributor a while back so any new parts should be fine to install as is.
Also, as stated on the distributor page, check your PCV system/etc to make sure everything is working properly.

 

[ADDvanced]

PCV valve is maybe 7k miles old, replaced it when I did the plugs a few months ago.

 

[AstroWill]

Good to hear!

 

[ADDvanced]

Update: Pulled the doghouse, and replaced the distributor, new cap/rotor (brass), had to twist the oil pump key a bit with a huge screwdriver but other than that went in without a hitch.

Two things tho: My distributor had no vents, and no clogs, I could see through the little passages. Secondly, the cap I had on there was brass, and the corrosion was white, then green, then thick black mold looking on the thickest buildup.

Given that the screens were not clogged, I am at a loss as to why this happens. Again, COPPER electrodes in the old cap! Still corroded like crazy! Why does this keep happening?

 

[Rod's Trucks]

An electrical ARC creates ozone, which is probably what is causing the corrosion.
I have no idea why yours is apparently much worse, but I think is is the main contributor causing the corrosion. All distributor ignition systems have to generate enough voltage to bridge that gap, and the one at the spark plug, so I have wondered why are the GM ones seemingly more prone to this problem?

Rod J
Issaquah, ,WA

 

[Mmusicman]

(Thinking out loud)
The spark is triggered by the CPS (crankshaft position sensor).. not the distributor.
If the distributor indexing was off (lets say by a tooth).. it might cause the spark to jump a gap.
I have no idea if it can run being "off by one tooth" or not.. but I'd look into it.

 

[kenk]

years ago there was a spray you could buy that would seal the cap and wires

 

[WoodButcher]

You can wipe on silicone spray, same stuff I use on my door rubbers but it will not stop the issue in the cap. It was mentioned prior, "ozone"? the big problem for the cap and rotor in my case was the corrosion caused by the spark.
New cap n' rotor would last a year, clean it I would get another 6 months. I just kept a spare and change it with the oil every spring. Done.

 

[ADDvanced]

There has to be a solution. I put a bead of dialectric grease on the distributor itself, where the cap meets it. My thought it maybe moisture runs down the cap, and gets pulled into the distributor cap via capillary action? The grease should prevent it.

 

[ADDvanced]

One other thought: Adjustable rotor? Maybe set the engine at TDC and see where the rotor is at?

 

[CopperFiremist]

Are you getting spark out of the coil? I just remember awhile back I had one where the white wire on the module connector had broken under the insulation.

 

[ADDvanced]

Yes. It runs fine til it doesn't. Every time it is corrosion under the cap.