wire arch
Thread Starter
1st Gear
Joined: Aug 2006
Posts: 1
Likes: 0
wire arch
My 85 was running rough when I accelerated, so I applyed the old turn the lights off in the garage at night trick, looked under the hood and noticed a christmas tree light show under the hood. With 60,000 miles i guess correctly that my wires were shot, so I replaced them and the plugs with new. This improved preformance and gas milage to expectation. Problem is when I tried the same process with the lights off in the garage, although minor i still can see a little inconsistant arching going on at # 2 & 5 cylinder in the area of the spark plug boot (can't tell cause it is dark). Checked all the connections and their tight.The car isn't running noticably rough. But should this be normal. 
If not what next?
If not what next?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Wires carrying very high voltage cause the air around them to be ionized and that air glows a light blue and is called corona. A spark is very bright, makes a snapping sound and looks like a jagged line. I suspect that you are seeing corona and if you don't notice any missing, then your plug wires are doing their job and allowing the spark to occur at the plug gap.
Instructor
Joined: Jun 2006
Posts: 124
Likes: 0
From: Arlington Texas
Corona!! That sounds cool. i never even heard of it, but it makes sense. So off to the garage I go. Well first I drag all the go carts and lawnmowers out so I can actually get my car in for a brief moment, shut the lights off and walla! Nothing! My 1990 vette aint got no corona 
But i did find a loose spark plug wire, maybe this has something to do why it cant pass inspection.
You might wanna take a flashlight with you so you can make for certain that it is corona and not just a loose wire. My new wires were all not pushed all the way to the end of the boot, so if you try to plug one on without looking inside the boot first, it pins the sparkplug between the back of the boot and the outside end of the wire terminal. The wire feels like it is locked in as you push it on. But if you tug back away from the engine on the wire, the wire moves even though the terminal is held onto the spark plug. When a plug wire is properly put on, when you try to pull away from the engine the wire does not move at all because the terminal has it held at a 90 degree. I know this sounds trivial, but I just discovered from this very thread that when I changed my plug wires last week that one was not put on properly. Took it for a test drive and I can now bark in second gear. WhooHoo!
But i did find a loose spark plug wire, maybe this has something to do why it cant pass inspection.You might wanna take a flashlight with you so you can make for certain that it is corona and not just a loose wire. My new wires were all not pushed all the way to the end of the boot, so if you try to plug one on without looking inside the boot first, it pins the sparkplug between the back of the boot and the outside end of the wire terminal. The wire feels like it is locked in as you push it on. But if you tug back away from the engine on the wire, the wire moves even though the terminal is held onto the spark plug. When a plug wire is properly put on, when you try to pull away from the engine the wire does not move at all because the terminal has it held at a 90 degree. I know this sounds trivial, but I just discovered from this very thread that when I changed my plug wires last week that one was not put on properly. Took it for a test drive and I can now bark in second gear. WhooHoo!
