bad plug wire causing wire to jump off plug?

[Huntervf]

Ok, here's the prob:

Got my 89 back with the new head, but #6 spark plug wire kept popping off. Determined that there was a compression leak and figured that's what was pushing the wire up & off the plug. Went to my machine shop today & they did a little milling on the spark plug seat in the head. Put everything back together, the plug seats properly and no more compression leak. But the wire is still popping off! In fact we saw the wire pop off with just the ignition engaged, without the car running at all. Now I'm running 8mm wires and #6 has a tear in the top of the boot where you'd push it down on to the plug. My question is this: Could a bad/shorting wire result in the wire "jumping" off the spark plug?

 

[NiNeTy Fo SHO]

I had the same problem about 3 months ago. I would be driving along (or just start the car)and all of a sudden I would be running on 5 cylinders...the wires would just jump off the spark plug. I replaced it with an older one I had and it stopped...but then another would do it...long story short, I bought a new set of wires and have not had a problem with them coming off since.

 

[sdpatt]

That problem is due to an improperly fitting plug boot. The metal clip in the boot does not engage the top of the plug correctly. I've seen that with several aftermarket wire brands. It's not a problem with Motorcraft wires.

 

[Mike Kopstain]

FWIW Chris, AC Delcos, Magnecor, Taylor, and obviously Motorcraft all seem to fit very well.

 

[Huntervf]

Well I ran these 8mm wires for the last 6000 miles with no problems. Yesterday I swapped a motorcraft wire on #6 to see if that took care of it. Well the wire doesn't get "blown" off like before, but it's still being forced up. Not enough to cause a misfire but after a 10 mile drive the wire was up a 1/2 inch so something screwy is still going on. shrug

I'm going to replace all the wires with motorcraft wires this morning, and I'm also going to replace the passenger rear intake support bolt with the original design. My shop replaced the intake bracket bolts but they also replaced the "special" bolt on the pass rear. In fact I found the ground strap just laying back there not fastened to anything. I put it back on but it's against the painted bracket insted of two nuts, so perhaps it's not making good contact.

I'll update later today, thanks all for the help!

 

[Bluto]

If there is oil in the plug wells, it will cause the plug wire to pop up just a bit.

The more oil in the well the higher it will pop off.

 

[sdpatt]

What plugs are you using? Many of the non-Motorcraft plugs are too tall to let the boot fit all the way down to the valve cover.

 

[Huntervf]

Well the problem looks to be solved. It wasn't a fitment issue...motorcraft AGSP-32-pp's with motorcraft wires and no oil in the plug wells (the front head is brand new and the car had it's 60k less than 6000 miles ago).

It appears to have been an electrical issue...rather than post the full explanation here just check this thread I posted in the open forum:

http://www.shoforum.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=30;t=003575;p=1#000000

This explains everything that my 89 has gone through in the past two months or so.

And thanks everyone for the help!

 

[bigpappy]

I had the #6 plug wire pop out after I changed my plugs. I'd pop it back in; it's pop out. The third time, it stayed in, no problems. In my case, it must have been operator error.

Good luck.