Got an engine miss devoloping...

[89Suburban]

Last night on a cruise I started getting a miss, feels like a spark miss, and is very random and mostly under a load or sitting stopped at a light in gear. Not really a pattern to it like it is the same cylinder. Everything in the ignition just about has been replaced just about. Just popped up out of nowhere. I am going to check the coil screws that hold that steel thing together, and check the cap and rotor. If I see nothing I will start checking plugs I guess, just wondered on your thoughts of where I should look.

Plugs, coil, module, cap and rotor, wires are all under 6 months old.

Not too bad of a miss like shaking the truck, just very annoying and enough of one to notice something is not right.

 

[bucket]

I remember you put cheap wires on it that were junk right from the start, then put better wires on it, right? Is it still a cheap cap/rotor on it?

 

[89Suburban]

I got the copper terminal cap and rotor. I am opening her up now.

 

[89Suburban]

The terminals had some green **** on them again. Like sulfur or something. I cleaned them off and it seems fine now. This happens every couple a months and I cannot for the life of me figure out why.

 

[RetroC10Sport]

Copper turns green when it oxidizes....Look at the statue of Liberty.

 

[crazy4offroad]

Get a tube of dielectric grease and put on all the terminals that are turning green. I would put it on both ends of all the plug wires too if I were you.
http://www.autozone.com/autozone/ac...electric-grease/_/N-255s?itemIdentifier=34495

 

[bucket]

The terminals had some green **** on them again. Like sulfur or something. I cleaned them off and it seems fine now. This happens every couple a months and I cannot for the life of me figure out why.

Maybe from all the time spent sitting at the boat dock?

 

[crazy4offroad]

Maybe from all the time spent sitting at the boat dock?

Hmmm, you think he might have had a couple too many and backed in too deep to get the boat one night??

 

[bucket]

Hmmm, you think he might have had a couple too many and backed in too deep to get the boat one night??

Haha, yep, that's probably what it is

 

[dhamp]

Man, my TBI has liked nothing but ACD caps since day one. The last time one was put on it, the ACDs were out and it's had a slight random miss every since. It's really bad on very damp/wet days. In hard rain, it'll even die at red lights, but cranks back up. They're not expensive, and you have to pull it off anyway to grease the contacts. When/if it starts again, might as well get a new ACD one and grease the contacts before putting it on.

 

[89Suburban]

Upon hooking the boat up and towing last might problem is still there, I will have to check the plugs next.

 

[Jims86]

I am wondering about that free coil and ignition module. If it was a more even miss, like a certain cylinder, i could tell you how to find it, but this sounds like the coil or the module. you can hook a timing light to the coil wire to see if there is a skip, that way you you know if its ignition, and not fuel droplets from dirty injectors....oh yeah, while the timing light is hooked up to the coil, point it at the injector spray...they should kinda look like they are alternating, or "breathing" back and forth.

 

[89Suburban]

I am wondering about that free coil and ignition module. If it was a more even miss, like a certain cylinder, i could tell you how to find it, but this sounds like the coil or the module. you can hook a timing light to the coil wire to see if there is a skip, that way you you know if its ignition, and not fuel droplets from dirty injectors....oh yeah, while the timing light is hooked up to the coil, point it at the injector spray...they should kinda look like they are alternating, or "breathing" back and forth.

Good advice. Another thing I just thought of is I remember my mechanic said he put a cooler range spark plug in, they are AC plus, but the next cooler range down, I wonder if that is the problem and a plug is caked up with chit. I don't know why he did that. It is a stock motor.

As far as that dielectric grease, that is what caused my problems with the last set of wires, it came with it pre installed in the plug boots and it was shorting out my spark and shocking the chit out of me so I stay away from that crap. I have not ever heard of it being used inside the cap though. How many of you do that?

 

[dhamp]

Those sound like faulty wires. I've run it on spark plug tips as long as I can remember and never had that happen.

 

[Jims86]

Yeah, never had a problem with the grease. As far as plugs go, stick with the Delco RS45's.

And while your at it, there are some screened vent holes in the bottom of your distributor, make sure those are clean, maybe use some electrical cleaner...might be locking moisture inside the cap and causing your issues.