Header Pipe Near #6 & #7 Plugs Very Hot, Melting Stuff & Plug 7 Erratic Timing


Active Member
Mar 7, 2016
Woodbridge, VA
Hey guys,

My #6/7 spark plug area seems to be getting rather hot at idle, and it gets hot quickly. First noticed it the other day when I was pulling my spark plug wires to check resistances. My #6 boot and wire were melted bad (see pic). I have since put thermal boot covers over the boots, but today i noticed smoking in that area, and found that my wire separator near the #6 and #7 was melted, and i just installed the separators to other day (see other pic). Just got out the old infared thermometer and recorded temps 600+ degrees F on the header pipe near the #s 6 & 7 plugs whereas the other header pipes were significantly cooler.

What could be the issue? :shrug: I have no idea. I recently did a compression test, and all cylinders passed, if that makes a difference. I'm also good on vacuum.

One thing i did notice today was that cylinder #7 seems to be behaving erratically (misfiring?). I was checking the timing, and for the heck of it, i decided to check each plug wire's reading relative to its timing counterpart (opposite posts on the distributor--the wire for plug 7 is opposite of 4, opposite of 6 is 1, etc.). The timing for the #7 was jumping around. I could sporadically see the base timing marks. What the heck is going on? Tfi or spout problem? I did the "relative timing test after the spout was popped back in; maybe i should do it again with spout removed to see if it's an issue with the eec advance of the timing?

Anyway, i imagine the weird timing/misfire thing could be related to the extra heat that melted stuff?

Thanks for your input. God knows i need it!:flag:


Last edited:
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Active Member
Mar 7, 2016
Woodbridge, VA
So i checked again today, and it looks like my right bank headers are also getting north of 600F degrees, and my left--the one i was worried about--is getting north of 700F. This is less of a difference than i saw yesterday, so im wondering if these are normal temps at idle? Im assuming yes as my coolant hose temp is coming in south of 200F, which i understand is good.

Im still getting that erratic timing reading on plug wire 7 though--even with spout removed. Is this a misfire situation?
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