I have a miss once the engine warms up. There is an intermittent arc from the coil wire to the distributor to the smaller terminals. I swapped the coil, wires, cap, rotor from my other 240 that had no ignition issues. I also and replaced the plugs..still have arcing. I am guessing that something else is interfering with the high voltage getting to the plugs, but can't find it. What should I check next?

Have you tried it without the black plastic cover?

You could have a track of burns running through the black plastic that is your culprit.

It looks like there was a bad crimp on one of the spark plug wires. When I went back to check that the spark plug wires were firmly on the plug I noticed one felt odd. When I pulled it off, the metal end stayed with the plug. Not having a spare wire set around, I cut it off and reattached it. All is now well. Thanks to all for the suggestions.

If you're using Bougicord wires, end of wire repairs are easily done.

Slowly pull wire out of boot (to prevent any more internal breakage), undo the terminal's crimp, remove the wire's metal conducting bit, cut off the defective wire, re-insert the metal conducting bit at new wire's end, check conductivity with voltmeter, if good then re-crimp (simply using pliers) and push back terminal end into boot (with some lubricant such as dielectric grease) and its done.

Regards,
Amarin.

I recently had some troubles on a dewy morning. Your symptom points to an open wire, open rotor, or unseated wire terminal, but once you've addressed the wires, cap, rotor, and plugs, you might want to finish like this.





--
Art Benstein near Baltimore

"Never trust the work of the last guy, even if you're the last guy"

Check your grounding cables and battery cables for voltage from end to end of the cable. I think your engine is not grounding well, or you have loose/bad connections from the distributor to the plugs/head.

Good Luck!

Hi,

I thought you had thus fixed a few days ago by changing into new wire. I guess the old got back on the car?

I need you to explain this statement. "There is an intermittent arc from the coil wire to the distributor to the smaller terminals." What are you calling smaller terminals?

On the distributor cap there are only spark plug wires.
If you are talking back at the coil top, you have a + and a - of the primary circuit.
The secondary circuit that will include the coil wire, cap, rotor spark plugs wires are designed to also seek the ground or -negative side of a Direct Current circuits.
Is it arcing on the top of the coil from the tower portion?

Electricity is lazy and will try to find a path of least resistance to ground wherever it can.
If you are having an issue of arcing you have an insulation problem.

Under high voltage conditions the electricity has even a better chance of being lazy.
High voltage is higher potential difference and IS able to jump even lousy ground paths.
The problem is extra resistance along the ignition systems pathway.
That higher potential is building up along the path until a double shot can reach out and say, HELLO!
Bad wires or rotor conductivity is the issue here almost all the time.

Do this! Grab the car with one damp hand, for a good grounding point and slide another damp hand around all those wires where you see arcing. Then you will say..... Whoa and HELLO TO YOU TOO! You got to the problem.

Better yet to truly find out what is meant by built up POTENTIAL, see if you can talk your brother or a not so nice acquaintance into doing that above!
If you don't see him feel the pop with a shake, you will feel one and learn what a "short" is and a "easy pathway" meant to him, coming back at you! (:-)
If the engine WAS missing you better hope he does the same thing!
Welcome to VERY BASIC troubleshooting but now with one fewer friend or relative. (:-)

A Fresh Tune up is needed.
Phil

The terminals are the small positive and negative ones that are on the coil. The arcing is from the large wire going to the distributor and these terminals.