Arcing from plastic!?

[naughtyG]

So yesterday I finally got my carbs back together, and refitted them to the bike. Got it started, warmed up, idle set, carbs synced again.

By then it was dark, and as I took a good look at the running motor to make sure of no leaks and everything A-ok, I noticed, on my rear left cylinder, sparks flying!

Best pic I could get of it:

and the same picture with flash on:

Looking at the whole head, I saw that while the arcing happened constantly on the right, it also happened sporadically on the left:

and again the same with flash on:

Now, those arrowed bits are the rubber nipples of the boot cap where it connects to the (plastic) heat shield.

So my question is, how the hell does arcing occur between metal (cylinder head) and PLASTIC/RUBBER ?!? :ummm::ummm::ummm:
It was also a nice dry evening yesterday, so there was no water or humidity anywhere near the motor. Isn't this strange? Another good reason for going to COPs IMHO..

 

[naughtyG]

Anybody got any suggestions on this? What would be the reason for these sparks jumping from the rubber, and how will it affect my motor?

 

[richwrench]

Never seen it on a VMAX, but being an old Chrysler guy, I say double check ALL GROUNDS. Even add some extra grounds - from motor to frame- frame to battery, etc. Can't have too many grounds. Loss of ground can cause some crazy problems. Some kinds of rubber contain carbon & will allow a high voltage to track through - I've seen vacuum hose carry a spark on Mopars - just my 2 scents...

 

[richwrench]

Those plug wires don't look new either - maybe some leakage there.

 

[kevman]

I have seen sparkplug leads and caps breaking down and shorting out which is what your leads seem to be doing .So I would replace your leads 7mm and your caps /boots and I think you can live without the plastic covers as well.You can damage your coils [maybe]but your bike will definitely run better with the spark actually going to your sparkplugs and not your engine.Kevman

 

[jfeagins]

IF anyone ever figures this one out for sure, let me know. It's plagued me off and on for a number of years now. Always after the bike is warmed up, and it is usually worse when the outside temp is hotter. Sometimes it won't do it at all on cooler days. When this happens on two cylinders simitaneously, DOA. At a stop light in town, this can be a real pisser.

Back when this first started happening to me, I put in new plugs, plug caps and plug wires. It got much worse immediately. That is when I learned how to properly install the coil end of the new plug wires, and not merely shove them in 'a little'. Thought that would fix it. NOPE. I then examined the coils with a magnifying glass and have spotted ZERO cracks.

I finally got a small amount of relief by removing the plastic cover from the top of my rear two cylinders. NO plastic near the valve cover = larger gap for the errant spark to jump. Mine doesn't jump around near as much as it used to, but I'm open for suggestions if anyone has run into this problem and definitely found what causes it.

:ummm::ummm::ummm::ummm::ummm:
:bang head::bang head::bang head::bang head:

 

[maleko89]

Jeff, what plugs are you running? Try lowering the gap a tad? Also, make sure plug seat is clean.

 

[naughtyG]

I think Rich may be onto something with the grounding issues, especially since the motor is mounted on rubber! I will check this out at the weekend and report.

I'm about to go for the COPs mod so that may end up being my fix anyway, but if not, adding a proper ground strap between the engine and the frame (if there isn't one already) could help a lot indeed.

 

[daves86vmax]

mine was just recently doing the same thing only on both rear cylinders.I replaced the wires with some 8mm taylors I found on Ebay for 15.00 and picked up some new caps(NGK SB05F Cap 8080)from www.powersportsuperstore.com for less than 4.00 each,put it all on and no more arcing.mine was so bad i could hear the arc snapping and could kill the motor by touching the cap and the frame at the same time.The front two wires were a pita to get in the coils but they did go on.good luck

 

[lankeeyankee]

Never seen it on a VMAX, but being an old Chrysler guy, I say double check ALL GROUNDS. Even add some extra grounds - from motor to frame- frame to battery, etc. Can't have too many grounds. Loss of ground can cause some crazy problems. Some kinds of rubber contain carbon & will allow a high voltage to track through - I've seen vacuum hose carry a spark on Mopars - just my 2 scents...

This is called rigging shit and not finding the root of the problem and possibily inducing new problems.
Obviously this hasnt always been a problem. So it must mean something is wore out or broken. Search and fix the root of the problem rather than trying to polish a turd into a leather biscuit

Most likely your boots are cracked, NGK sells replacements real cheap, I am betting your wires are fine, just replace the caps with NGK's and screw your old wires in. Or spend the extra bucks and buy new wires.

 

[maleko89]

IMHO, stock wires/caps go bad quick. Almost 5K Ohms more than the NGK setup so spark would rather jump to engine than fire the plug.

 

[lankeeyankee]

IMHO, stock wires/caps go bad quick. Almost 5K Ohms more than the NGK setup so spark would rather jump to engine than fire the plug.

Its beacuse your adjusting your floats to much!!
I am still running my orginal 98 wires on this 4th engine. I have replaced the caps though,, the secret is using seafoam with each fill up this keeps the wires conditioned

 

[maleko89]

If you adjust your floats you get to keep the same engine. 1st one....over 70,000 miles.

 

[lankeeyankee]

If you adjust your floats you get to keep the same engine. 1st one....over 70,000 miles.

Well its not from my floats, I just tore apart all my engine to inspect why all had rod failures..

Engine #1 Had a refried bean in the oil passage way in the crank journal.
Engine# 2 Had pieces of burrito clogging my oil pickup screen.
Engine #3 Had Excessive amounts of Salsa in the oil..

:confused2:

 

[maleko89]

There's a lesson here....try different burritos. Your Max doesn't like your current ones.

 

[richwrench]

This is called rigging shit and not finding the root of the problem and possibily inducing new problems.
Obviously this hasnt always been a problem. So it must mean something is wore out or broken. Search and fix the root of the problem rather than trying to polish a turd into a leather biscuit

Most likely your boots are cracked, NGK sells replacements real cheap, I am betting your wires are fine, just replace the caps with NGK's and screw your old wires in. Or spend the extra bucks and buy new wires.

I agree 100 %, but you have to admit that original VMAX wiring is minimal at best. Factor in age & corrosion & problems are sure to surface sooner or later. The charging system on my '96 was a joke - a single 16 gauge wire from the R/R through connectors & fuses before reaching the battery - no wonder the battery was always weak. I doubled that circuit & added an extra ground also - no more problems. I also agree the boots/wires are probably shit - I recently put silicone wires & NGK boots on my bike & it's running great now - no extra sparks floating around. :biglaugh: I won't hesitate to upgrade a system that I feel engineers neglected when they originally designed it. Sometimes things are designed to save money - not live a long life. Toyota puts redundant grounds in their vehicles so that if/when a ground fails, there's another one already in place to pick up the slack - the owner never notices a problem. Now THAT'S smart engineering... :clapping:

 

[COP RUNNER]

I SEE WIERD SHIT LIKE THAT ALL THE TIME AT WORK ! , I BET IF EVEYONE ON THIS FORUM WITH A 10 YEAR OLD CAR THAT WAS NEVER TUNED UP , WEN'T OUTSIDE AT NIGHT IN THE PITCH BLACK & STARTED THIER ENGINES , 3 OUT OF 10 WOULD SEE ARCING SOMEWHERE ! EVEN IF A IGNITION WIRE IS LAYING AGAINST SOMETHING , SOME OF THE SPARK WILL TRAVEL THROUGH WHAT EVER IT IS & JUMP OUT OF IT TO SOMETHING ELSE NOT EVEN NEAR AN IGNITION WIRE ! BUT IT HAS TO BE REAL BAD TO CAUSE A MISFIRE ! YOU NEED NEW IGNITION WIRES & I WOULD ALSO PUT IN NEW SPARK PLUGS !unk:

 

[naughtyG]

Going back to this thread, because I realized that even tho I have now been running coils over plugs for a number of months, if I touch the rear left cylinder rubber cover (wrapped around the COP) I get shocked!?

Still don't get how electricity could be running out of the COP and through rubber?

What do you guys think, should I try replacing the rubber with brand new?

 

[richwrench]

I've seen rubber with a high carbon content (like vacuum hose) carry secondary voltages quite easily. What if you trim away some of the rubber away from the coil - give it a big air gap ? I'm at work now - I'll look at my bike this evening.

 

[ssnsltd]

G- have you swapped sticks around to rule out/in the coil as the source ? sure you know this, but they absolutely should not be "leaking "