Skip the auto shop - Our mechanics make house calls

Q: Plug wire attached to the distributor cap are arcing from the wire to the distributor cap.

asked by on

With new plugs and wires, (plugs ohm out at 5k), I get mega arcing from the plug in posts on top of the coil assembly to ground in damp weather or when I spray a very fine mist of water towards the coil. Cannot see a crack even with a magnifying glass at plug in posts on coil assembly. The arcs are about 1/2" long from bottom of wire boots to ground. With just a normal small gap in the plugs, why does the coil top still arc. What happened to the "path of least resistance"? Why doesn't the plug fire instead, or is 5k ohms on a plug enough to make coil charge seek a easier path. The codes came up Po300, 02, and 04 all at once. # 2 and 4 plug in posts are the ones arcing. Just want to make sure I'm not missing something before I get a new coil assembly. Thanks for any input.

My car has 125000 miles.
My car has an automatic transmission.

Hi there. The spark plug wire is arcing for there is a least path of resistance on the distributor cap. There could be a crack in the cap, but most of the time the spark occurs due to lack of connection. Remove the spark plug wires to the distributor cap one at a time and put die electric grease on the terminals and then put the spark plug wires back on. Allow the one hour for the die electric grease to seal up tight. This will prevent the wires from shorting to the distributor cap. Also, remove the distributor cap and check the terminals on the cap and on the rotor. Use sand paper to clean up the corrosion that is present on the parts. Put the distributor cap back on and recheck for any sparking. If the sparking continues, then either the cap has a crack on it or the terminals have too much corrosion causing an arc. If you need further assistance with your distributor cap arcing, then seek out a professional, such as one from Your Mechanic, to help you.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Plug wire attached to the distributor cap are arcing from the wire to the distributor cap.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Bolt on 06 Elantra control arm no longer attached

The repair will depend on whether the arm detached and as a consequence got damaged. Also, detachment of the arm if the vehicle is moving can potentially damage other parts such as the mounting boss(es) on the frame that the...

Q: Car leaking coolant from flange.

You may need to have the radiator hose clamp replaced. I have had problems with the spring type connector on the hose. You should change them out to the screw on type clamp. I would recommend having a technician from...

Q: Want to install an aftermarket trailer hitch on my car

I did a little research on this and yes, you can. One hitch that will definitely work is the Curt 13129 Trailer Hitch. There is ample space between this hitch and the sensors for the lift gate.

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...