Spark Plug Problem?

[habitatguy187]

Ok here's the story, today on my way back from my lunch break I decided to open it up on the highway, as i'm accelerating I look in my rearview for cops and see a big puff of black smoke come out of my exhaust. So I'm like, "man that sucks...." and when I pull off the highway my car's running like a beater. (actually, it is a beater)

So anyway it's just missing out real bad so I think that maybe I have a valve cover leak and all the oil pressure from the boosting on the highway pushed some oil into my spark plug wells (plugs and wires are 6 days old, gapped properly) So after work I go some places and then come back and take out my plugs and look at them, find a LITTLE oil, clean them off with a wire brush, and try to clean the wells with a paper towel.

Put everything back together, start my car, idles fine again, but about .3 miles down the road it starts missing out again, and continues all the way home. Is this because I didn't get all the oil out of the wells? Do I need new plugs again? Or is it related to the puff of black smoke? Thanks

Forgot to add that I don't have a CAT, and I saw someone say that their car smokes black under WOT because they're catless, didn't know if it was true or not

 

[nlzn]

If your valve cover was leaking oil into the spark wells (and assuming you have the plugs torqued down) oil can't very well leak into the chambers.
This leak would only cause a massive problem if so much oil was leaking on the plugs that they were submerged which you said wasn't the case.

If you're getting a ton of black smoke there's definitely fuel not burning off. I'd rule out the valve cover causing this and start troubleshooting elsewhere on timing, compression and ignition components / sensors. Spark can be checked pretty easy via laying a screwdriver in the boot then laying it near the VC or something grouned and seeing the arc.

You may also want to check the boots and the connection ends of the wires you bought, I've seen cracked boots straight out of Bosch wire packages before for a Nissan KA.

 

[98 Mits GS-T]

Not to contradict but, when you take a screwdriver to the spark plug wire and check the spark you need to add about a half inch gap in between the screwdriver and your ground to simulate the compression that the spark has to jump when it is inside the cylinder.

 

[kenamond]

There is a Magnacore article somewhere out there talking about the problems oil in the wells can cause with ignition. Basically, if you get water or oil in the wells, the wires can arc through the boots instead of across the plug gap, causing misses. If you or someone can find the article, you can get more details. They indicate that you can find small holes bored through the boot that have white around the hole...I'd search for it and find out more for yourself.

Anyway, I suggest you get a VC gasket kit, search about how to change the gaskets without breaking your VC (I did) and fix the leak. It might be coming from a leaking oil cap seal, too. But if you don't have any oil under the plug cover (bolted to the top of the VC) then it's gotta be a cracked VC or bad plug well seals.

The moral of the story is that you don't want water or oil in your plug wells or you can have misfire issues due to a "short" at the plug wire boot.

Or - as has happened waaaaay too many times in the past - it's something completely different, and I'm just yammering.

 

[nlzn]

I think the article referred to above is here:

Magnecor Race Wires: Mitsubishi twin cam technical bulletin

I searched for that after the above post and I would have never noticed those pinholes without it.

 

[habitatguy187]

Alright guys got it figured out. I started checking and cleaning my plugs and wells today, and when I put the air hose into one of my wells I heard something rattling around, so I took a flashlight and looked down into it, and then pulled out a washer from a spark plug. I still had all my old plugs (from last weeks change) so I looked them all over and they all had washers.

So this washer must've been from 2 spark plug changes ago. I also had another plug that was all warped at the tip, a mechanic I know said that I could've had detonation (cause of the black smoke) and burned up the spark plug. He said that I need to clean my intercooler because it could be inefficient and under high loads cause detonation. Haven't done that yet, but either way, it's fixed now, just replaced that crappy plug and pulled out the old washer.

Thanks for all the advice guys, I just keep learning more and more.