Burning, melted coil pack

[Arqi]

Long time no see Nico! Wow, it has been a long time sense I last posted here. Missed you guys.

Anyway now on to the topic/ problem at hand.Car: 1997 240sx w/ SR20DET Black Top at 12psi.

After a little "spirited" driving ( Tehehe) I stopped at a light and after about 5 sec the car started to vibrate, then I started to smell something burning and soon after that i saw some smoke coming from the engine bay. I pulled over and popped the hood, i saw that the smoke was coming from under the spark plug cover. Not far from home I babied her the rest of the way. I removed the spark plug cover and this is what I find....











I think its obvious where the burning smell and smoke was coming from. It looks like most of the damage was to the wire harness and little to the coil pack. Now that we now what the problem is, now I need your help to find out what would cause this.I did a quick search and found that maybe a leaking valve cover might cause something like this.I removed the coil pack and found a gooey, kinda sticky substance around the base as well as what appears to be oil on the underside corner of the spark plug cover...













Now for the questions...What happen here?Do I need to replace Coil Pack w/ harness or just the harness?How do I test Coil Pack?Anything else i should look at that might have coused this?

And yes I am for sure going to replace the valve cover gaskets.

Thanks for the help guys!

Modified by Arqi at 8:20 AM 10/29/2008
Modified by Arqi at 8:21 AM 10/29/2008

[RPS13 DRIFTER]

if you can find another coilpack harness conector you can rewire it to it with a new coil pack and valve cover gaskets,you should be set, it was probably caused by oil in thespark plug hole and and heat make it melt,,btw leave the intercooler turbo thing off it causes alot of heat under there in my opinion. thats my 2 cents

[burntricer]

definatley wasnt oil around the plug that caused that, my old vc gasket leaked quite a bit, and i never had a problem like that, ive even had the spark plug almost covered in oil...

[Emperor_Tha]

this happen to my friend. It's on the same clylinder as u number one. Unknown cause probably just bad luck or internal arcing. He replace the coil pack and and harness. 8month later still no problem

[IDriveFords]

probably a bad coil pack since it only toasted that part of the harness and you said it ran home probably on 3 cyls. There should be a ground coming off that part of the harness which should be grounded to the block or chasis... just make sure thats still connected.

[240_SeX]

definatley wasnt oil around the plug that caused that, my old vc gasket leaked quite a bit, and i never had a problem like that, ive even had the spark plug almost covered in oil...

Im not sure if you know or not, but oil will eat rubber and plastic.

Im willing to bet that is exactally what happened here. The oil ate into the coil, caused a short and lead to the burning.

You should replace the coil, valver cover gasket as well as the five seals (4 for the plugs and one small one) and repair or replace the coil harness.

[the converted]

Double check the ignitor while you are at it. If the driver for the coil failed it's possible that it could do that to the coil. Probably didn't but better safe than sorry.

[Arqi]

Update!

Ive been leaning towards oil being the issue here, but from where? Valve cover? umm.. maybe. I paid a vist to Marko over at sr20store in Gardena, CA to pick up replacement parts. I asked what would cause this, he just said that they just go bad sometimes. Now the next thing he told me is that each coil pack is filed with oil. Once he told me that a lot of things started to make sense!

Closer inspection of the defective coil pack you can see a bulge along with a hole on top. It seems that the oil was cooking inside and building pressure like a volcano and eventually erupting releasing oil. This explains why I found oil in the under side of the spark plug cover which was in the line of fire based on the location and angle of the exit hole.





What about the gooey substance on the base of the coil pack? Well, I notice that all that gunk was meanly concentrated on one side of the coil. After scrubbing the gunk off the coil I found a fracture along with a hole on the base of the coil. Now this explains why I had gunk on the base of the coil.







Here is a side by side shot of a good and the bad coil pack. The bad coil has some orange discoloration to it.



I removed and replaced the old harness. I did a quick inspection on the old harness and found one of the cables seemed to have been pinched to a point that wire was exposed. Not sure where this wire leads to or if this might have been the caused of the coil going bad?







I also replaced the valve cover gaskets and noticed that only cylinder #1 had a dark ring around it. Looks like the Coil oil was trying to seep into the engine.





Well so far I've replaced Coil Pack, the whole harness unit, and valve cover gasket. Is there anything else I should look at or replace? So far the car has been running great Time will tell if i have any more issues. I will keep you guys up to date.

Thanks for the help guys!
Modified by Arqi at 2:04 AM 10/31/2008

[IanS]

Make sure to clean the grounding point. High resistance caused either by a bad ground or that pinched wire would have contributed to the coil over heating.