arcing spark plug boots

It's a 1990 3.1l v6.

Before I go buy a new set of wires & plugs & the correct socket...

What will cause arcing at the #4 spark plug boot? Am I right & the plug wires are just used up? Or, is it likely that the plug itself is buggered? Or, is there something else I should watch out for?

Last summer, My wife limped it into the shop with a plug that had blown itself apart & I was told they replaced all 6 plugs and put a used wire in to replace the one connected to the blown plug. I was under the impression it was the #2 plug but may be mistaken.

Any quick thoughts?

It's a 1990 3.1l v6.

Before I go buy a new set of wires & plugs & the correct socket...

What will cause arcing at the #4 spark plug boot? Am I right & the plug wires are just used up? Or, is it likely that the plug itself is buggered? Or, is there something else I should watch out for?

Last summer, My wife limped it into the shop with a plug that had blown itself apart & I was told they replaced all 6 plugs and put a used wire in to replace the one connected to the blown plug. I was under the impression it was the #2 plug but may be mistaken.

Any quick thoughts?

May be either one.
What kind of plugs did they put in in?
On a 3.1 always go for a good set of plug wire when ever the plugs are replaced.
A bad plug wire will make them go crazy.
If it is arcing replace the hole set and have a look at the plugs to.
And make sure to use the AC delco plugs the good book calls for.
MT
MT

Buy the damn plug wires...sheesh. Why try to overthink something you obviously need...

HEI ignitions do have the power to punch through insulators if there's a poor path to ground (ie a fouled plug), but only a really crappy old wire would get holed by that....remember when they had distributors? Sometimes they'd stop running after misfiring for a while...you'd take the cap and rotor off and find that it had shot through the plastic of the rotor to the grounded distributor shaft, rather than try to fire through a bad plug wire or fouled plug...whatever is the weakest insulator and shortest path to ground, that's where an HEI spark is gonna go...

I like the Delco/Packard wires...that's what i use on them...parts store wires, especially AZ and Advance are crap...won't last a year, regarless of warrantee.

Pull that plug and check it for fouling or bridging if you want...or just put the new wires on and if it runs fine, don't sweat ti...

Duramag. My ass. The originals lasted you 15 years, why go with anything else?

I agree, although perhaps not a vehemently, that the original Packard Electric wires lasted who knows how many thousands of miles, and over a decade and a half. I always get a little grin when people ask about getting "better" wires. How much better than that do you really want/need? You'd be lucky to get wires that are that "bad" so you don't have to worry about them for another 15 years. There's a reason the factory wires are $60 a set.

I agree, although perhaps not a vehemently, that the original Packard Electric wires lasted who knows how many thousands of miles, and over a decade and a half. I always get a little grin when people ask about getting "better" wires. How much better than that do you really want/need? You'd be lucky to get wires that are that "bad" so you don't have to worry about them for another 15 years. There's a reason the factory wires are $60 a set.

Testify!:grinyes:

I agree Blue and you tell 'em Jeff, Dura-poo and Boschit are useless. AC-Delco wires are far and above better than the aftermarket wires. The only ones even close for the money are Autolite Professional series and Taylor.

I've been told!

Yes, I'm getting the wires. Also a new socket so I can pull the plug & check it. I was going to pull the plug when I discovered the problem & found that, of the 4 plug sockets on hand, none fit. Won't replace the plugs if I can avoid it tho since I've lost enough blood this week working on this car.

Sorry to seem like I'm over thinking things. This car has done some of the weirdest things in the time I've had it & it seems that every time I fix something it just leads to another problem to fix that was masked by the previous problem.

Last summer I did the brakes & it blew a rear line 2 days later. Friday, on my way home from work, the brake warning light came on & I seem to be down about half a litre of brake fluid. Can't find a leak.

During the winter it dropped the tailpipe & when I replaced it, the connection between the cat & the muffler went, then it blew the muffler to hell. (It tossed the new tailpipe at the same time!) I spent eight hours yesterday rebuilding the entire exhaust system because the manifold to downpipe seal was leaking & there was no way I was doing THAT job without making absolutely certain the rest of the exhaust was rock solid and airtight. If I hadn't started to run out of steam, I'd have eliminated the remaining clamps.

I'm still trying to track down what has been making it run incredibly rich for the last six months or so.

Yup, the odometer has rolled over at least 5 times since 1990 and she's earned her keep. I just don't trust any easy fixes these days.

Holy crap! Must have been a tedious day at work today. I appear to have gone into venting mode. Sorry...

Actually, it's easy to remember when they had distributors. This one does.

DAMN!

New wires didn't do it. Just finished installing a brand new set of wires, then driving the evil thing to the hospital for 2 stitches in my left hand. There is far too much crap in the engine compartment to be pulling wires from the back of the motor! It's still arcing.

I also picked up the 5/8" plug socket while I was in town and pulled the plug out. Who the hell designed an engine requiring removal of the oil dipstick tube to get a socket on the #4 plug anyways??? Found out the bloody socket isn't quite deep enough to get onto the plug and still connect the ratchet. Fortunately, a 3/4" standard socket on the end of it did the trick.

The only indication of a problem from inspecting the plug was a fair bit of carbon buildup. Surprise...weak ignition...duh... Cleaned it up & put it back.

So now I guess I have to get new plugs. Of course, I can't find the plug recommendation anywhere & I forgot to read it off the existing plug. Anybody got it on hand? The engine is a 91 (yes...I said it was a 90 APV earlier...Just found out I was wrong when I looked through my records to see if the plug info was there...) 3.1L.

When you had the plug out, did you happen to check the insulator for cracks?

If you think changing plugs in that is a chore, try a set in a Ford 5.4L Triton 3-valve engine in a truck. You'll be reaching for the SawZall before long.

Just changed the #4 plug...

Wow...no sparks...at least none that I can see in daylight.

The old plug isn't cracked, just looks a bit discolored. Last nite, in the dark, I was noticing a bit of a blue glow around the plug when it wasn't actually arcing. I'm waiting for the sun to go down to look again at the new one and the rest of the old ones. Now I just gotta figure out how in hell to see the back 3.

Just changed the #4 plug...

Wow...no sparks...at least none that I can see in daylight.

The old plug isn't cracked, just looks a bit discolored. Last nite, in the dark, I was noticing a bit of a blue glow around the plug when it wasn't actually arcing. I'm waiting for the sun to go down to look again at the new one and the rest of the old ones. Now I just gotta figure out how in hell to see the back 3.

You know the trick, right? Remove the roll restrictors and flop the motor forward?

Only way to work on these in the rear bank....you can ratchet the motor forward with a ratchet tie down, rock it in park to make the motor flip, then stomp the e-brake to freeze it in place, butt another car up behind it and push, making the motor roll, etc...whatever works, just make sure you brake the motor with something, or at least chock the wheels so the motor won't come down if the brake stops holding it up....

And don't forget to put the restrictors back in... the motor will smack the radiator when you put it in gear...


Halo around the plug, huh? I've seen that when oily deposits and salt/metallic residue conspired to short circuit an ignition discharge from a wire, but only once or twice...

You know the trick, right? Remove the roll restrictors and flop the motor forward?

Yup...& with my luck I'll snap the exhaust while I'm at it...

Real problem here is...for now, I want to see those plugs with the engine running. Don't think it's adviseable to run it with the motor rolled.

And don't forget to put the restrictors back in...

Reminds me of the firsr rad replacement in this car. About a year after it was bought, the restrictor snapped. Would have cost a fortune to fix the rad, restrictor, throttle body and various other bits that got thrashed.

I knew it was arcing...the halo really got me. I didn't see it until after the side trip for flesh repair. If I had been in a little better shape when I saw it, I'd have been betting on plug replacement. Up until that point, I'd only seen the sparks shooting between the boot & the block.

On the up side, it's running smoother than it has in months. This is a good thing as we leave for Algonquin for a week on Sunday. If it was running like it was a few days ago, I'd have cancelled the trip.

Yup...& with my luck I'll snap the exhaust while I'm at it...

Real problem here is...for now, I want to see those plugs with the engine running. Don't think it's adviseable to run it with the motor rolled.





You can RUN it that way...no problem, just can't put in gear or drive it...but start and watch, OK. Never seen the exhaust take any hurt from it...FWD exhaust connections are built "sloppy" to accept a lot of rolling motion from the driveline with no adverse effect..

It sounds like your plugs are leaking spark from where the ceramic and metal meet. Change all the plugs and you should be golden. They are most likely the cause of the rich condition too. Bad plugs don't burn all the fuel, causing a rich condition.

Well...

Rolled the engine forward...no good, still can't see the rear plugs without sticking my head in there & my head doesn't fit. Gonna hafta get an inspection mirror. Also concluded that it'll have to be considered good enough for now as I needed my left hand to accomplish anything back there & it's not particularly functional at the moment.

On the other hand. it seems to be running pretty good so I'm content to let it be for a bit

As for the exhaust concern...it IS a 15 year old downpipe. I was worried it may be damaged when the engine is pulled forward. seems ok so far...

As long as you don't rock it too far, you'll be fine. The exhaust is spring mounted, so you have some flexibility.

As long as you don't rock it too far, you'll be fine. The exhaust is spring mounted, so you have some flexibility.

There's the funny part...

I'm betting it'll be fine now...

Not so a week ago. I just had the exhaust completely off to replace the seal in that little spring loaded connection. Whoever designed this thing should be forced to change at least 6 of those seals a day. While it was off, I welded up all the patchwork that's been done to the poor thing over the years. The only original parts on the exhaust at this point are the downpipe & the cat. There's about 3" of new pipe between the two & everything behind the cat is newer. I still don't trust the downpipe not to disintegrate soon.

If I'm smart, I'll get a new downpipe made up soon & say byebye to rusted out exhaust parts. Problem is...I live a long way from any muffler shop & they'd want to do the installation if I bring them the original still on the car.