What do you do when you discover carbon tracking on spark plug(s)?

[torqueman2002]

I'd like to get some feedback for a project and discussion at work.

If the service information does not specifically direct you to replace the spark plug(s) and wire/boot(s) at the same time, when there is carbon tracking, do you replace the wire/boot(s) any way? (this would also include coil-on-plug assemblies with non-replaceable boots)

If you'd care to say why or why not, I'm interested in hearing that; also, how frequently you've come across this situation.

Thanks for reading and taking the time to give me some feedback.

Mike

 

[bgott]

If you don't replace the wires or boots when doing a plug job on a high mileage car you are looking for comebacks. The combination of high heat, high voltage and age will cause the rubber to break down and give the electricity an easier path to ground after you've broken the original bond between plug and boot. Most of the time you play hell getting old plug wires off of the plugs without breaking a couple. Do I have the results from some million dollar studies to back this up? No, forty years of experience.

After I re-read your question, I replace the plug and boot/wire when I find a carbon track on a low mileage car. If it has fifty thousand miles or more I"m looking at all the plugs/boots/wires. Of course, I work in a shop so I do what I'm told. What I'm ordered to do and what should be recommended can be two different things at times.

 

[srmofo]

If you don't replace the wires or boots when doing a plug job on a high mileage car you are looking for comebacks. The combination of high heat, high voltage and age will cause the rubber to break down and give the electricity an easier path to ground after you've broken the original bond between plug and boot. Most of the time you play hell getting old plug wires off of the plugs without breaking a couple. Do I have the results from some million dollar studies to back this up? No, forty years of experience.

After I re-read your question, I replace the plug and boot/wire when I find a carbon track on a low mileage car. If it has fifty thousand miles or more I"m looking at all the plugs/boots/wires. Of course, I work in a shop so I do what I'm told. What I'm ordered to do and what should be recommended can be two different things at times.

thats my outlook as well

 

[Stick]

Replacing the plug and the wire is the only way to prevent a comeback with carbon tracking.

I also try to prevent pulling plugs/wires unless I am replacing them. Generally a couple minutes with the labscope will give me a definitive answer about weather or not something is an ignition problem, and if so, what the source of the problem is.

Edit: For whatever it's worth, on a COP system I generally just replace the bad plug/boot. On a DIS or conventional ignition system with individual plug wires I generally replace all the plugs/wires unless they had recently been replaced, in which case I'll do the individual cylinder.

 

[Phil S.]

O.K., This is going to be off topic but I got to thinking. First, What is carbon tracking??? I have a bass boat with a 2 cycle outboard motor. A couple years ago I changed my spark plugs, upon removing the old plugs I noticed what I think was carbon deposits that had collected at the end of the spark plug. It looked like little grains of black sand and they were as hard as steel. My question is if there are cabon deposits on my spark plugs would this be an indication that there are also deposits collecting at the piston rings?

 

[Stick]

O.K., This is going to be off topic but I got to thinking. First, What is carbon tracking??? I have a bass boat with a 2 cycle outboard motor. A couple years ago I changed my spark plugs, upon removing the old plugs I noticed what I think was carbon deposits that had collected at the end of the spark plug. It looked like little grains of black sand and they were as hard as steel. My question is if there are cabon deposits on my spark plugs would this be an indication that there are also deposits collecting at the piston rings?

Carbon tracking looks like a thin black line on the porcelain (outside) of the sparkplug, usually from the top to the barrel. It's from the carbon in the plug wire breaking down and creating a low resistance path for electrons to flow. Once that path is established, it's impossible to get rid of completely, which is why replacing both the plug and the wire/boot is the only fix. If you replace just the plug, the electrons will follow the path on the wire/boot, and if you replace just the wire/boot, the electrons follow the path on the plug. No matter how good of a job cleaning you do, you'll never eliminate all traces of the carbon path.

 

[Stick]

Ok, last thought for a moment anyway...

If the service information does not specifically direct you to replace the spark plug(s) and wire/boot(s) at the same time, when there is carbon tracking, do you replace the wire/boot(s) any way? (this would also include coil-on-plug assemblies with non-replaceable boots)

While it's not explictly spelled out, if a component is damaged or otherwise "bad" it should be replaced.

With carbon tracking, the plug is damaged, so it should be replaced. Likewise, the wire/boot is also damaged, so it should be replaced as well.

 

[theoldwizard1]

Silicon dielectric grease is a good preventative (a dab on the top) but it will not cure carbon tracking. It can also occur from the top of the old style oil filed coils down the side.

On any engine that does not have coil-on-plug there is a simple way of checking. Park the vehicle in a dark garage (doors partially closed, windows covered). Pop the hood. Start the car. KEEP YOU HANDS IN YOUR POCKETS ! Walk around the vehicle. It might take a minute or 2 for you eyes to adjust, but if you see any blue flashes (tiny lightening bolts), you have a problem. Use a flashlight to identify which plug.

Works on all engines, especially old outboards or other engines without electronic ignition.

 

[J Persons]

2008 Chevy Equinox V6@30,000 miles. It started running rough at highway speeds and the check engine light came on. Took it to the dealer and he replaced one carbon tracked plug. Two weeks later the same thing happened, took it back to the dealer and he replaced another plug and sent me on my way. Another two weeks and it was still missing and acting up at highway speeds. Took it to the dealer and this time he replaced the all plug wires and all the plugs. It's been good for about six months now. The local Chevy dealer swears he has never seen this before. It was all under warranty and on his nickle.

 

[Phil S.]

Carbon tracking looks like a thin black line on the porcelain (outside) of the sparkplug, usually from the top to the barrel. It's from the carbon in the plug wire breaking down and creating a low resistance path for electrons to flow. Once that path is established, it's impossible to get rid of completely, which is why replacing both the plug and the wire/boot is the only fix. If you replace just the plug, the electrons will follow the path on the wire/boot, and if you replace just the wire/boot, the electrons follow the path on the plug. No matter how good of a job cleaning you do, you'll never eliminate all traces of the carbon path.

Thanks for the reply. Obviously carbon tracking is not an issue for me and I appreciate your explanation. Thank-You

 

[torqueman2002]

Thanks guys, just the kind of feedback I'm looking for; keep it coming.

The poll is set to run 10 days, I will be reading the posts; at the end I will share what prompted the post.

Mike

 

[George in Rancho Cordova]

It wasn't on the dealer's nickel, unless it was done as "goodwill"
Even then, it affects the dealer's cost of doing business & will be covered somehow.

If the manufacturer paid, that was built in to the price of the vehicle.

 

[Lotek]

2008 Chevy Equinox V6@30,000 miles. It started running rough at highway speeds and the check engine light came on. Took it to the dealer and he replaced one carbon tracked plug. Two weeks later the same thing happened, took it back to the dealer and he replaced another plug and sent me on my way. Another two weeks and it was still missing and acting up at highway speeds. Took it to the dealer and this time he replaced the all plug wires and all the plugs. It's been good for about six months now. The local Chevy dealer swears he has never seen this before. It was all under warranty and on his nickle.

Either #1 or#5, always replace the affected plug and wire, just replacing the plug was a waste of time. Replacing all of them was a waste of money. Hope that shop is looking for a good driveability tech.

 

[bgott]

On the old cars that ran the old Delco/Packard carbon core wires you could do that and it would look like the Aurora Borealis under the hood! I can't remember on how many cars running those wires I've done a maintenance tune-up on and had the thing running worse when I got done. Great wire new, after 40,000 miles, ****.

 

[1949 caddyman]

What have you found on the Equinox on cyl 1 & 5 to warrant this ? I was a Chevy drivability tech for 25 years in AZ. I retired 2 years ago, never saw this problem or repair. Not trying to say your wrong, just trying to see what I am missing LOL. It was a good job until GM went bankrupt & car sales and repairs went to ****. Luckly I was of the age to get Social Security and am enjoying each day!