Spark plug woes

[Aloha Joe]

I decided to change my plugs since I don’t know their history (although I know they are some kind of Bosch 4-tip plug). I also recently changed my catalytic converter, so I decided to reset he ECU while I was changing the plugs. I bought the OEM/factory NGK copper plugs, checked the gap (sticker says .030 to .o035”, and these were all about .034”). I put everything back together and heard a ticking sound and the Jeep ran like garbage. I looked under the hood and saw intermittent sparks near one of the plugs closest to the engine. It kind of freaked me out so I put the old plugs back in, and the problem went away.

What’s wrong?

 

[KCsTJ]

I dont think its the plugs ..
Sounds like some arcing between the wire and the block.
Maybe cracks in the wiring? Maybe a plug wire was close enough to the engine block to arc.
..possibly when you reinstalled the new plugs , the wiring was oriented in a way that did not arc, just my speculation.

 

[dbbd1]

Was the arcing only on one plug?
If so, swap it around and see if it follows the plug or stays at the same cylinder. You may have a cracked insulator on the plug. Or, it may be the wiring.

 

[Aloha Joe]

Interestingly, 5 plugs show signs of use while 1 still looks brand new. I can’t see any defects with the naked eye.

It was late last night so I didn’t look closely at the plugs after I took them out.

 

[toximus]

Which year?

 

[dbbd1]

Interestingly, 5 plugs show signs of use while 1 still looks brand new. I can’t see any defects with the naked eye.

Possibly because it was arcing to ground outside of the cylinder.
With prolonged use of a bad plug, you might see where it was bad. Like I said, swap it around to a different cylinder.

 

[Aloha Joe]

It's a 2005 with the distributor rail, or whatever it's called.

I haven't had reason to learn the cylinder numbering convention yet, but I believe it was the cylinder closest to the engine. I honestly got a little nervous when I saw the spark so I immediately went to shut down the engine, rather than investigate more closely.

When I get home from work I'll swap the plugs again, and put the clean one in the front (where it's easy to get to and change).

 

[toximus]

Sometimes it can be tricky getting the spark plug boots all onto the spark plugs wit the rail. That boot is probably not on the plug. Try reseating.

 

[Aloha Joe]

Sometimes it can be tricky getting the spark plug boots all onto the spark plugs wit the rail. That boot is probably not on the plug. Try reseating.

I must have been pretty tired to mess that up. Thanks for the suggestion. It feels like a new Jeep

“My ________ isn’t working.”
“Did you plug it in?”

 

[Jerry Bransford]

I must have been pretty tired to mess that up. Thanks for the suggestion. It feels like a new Jeep

“My ________ isn’t working.”
“Did you plug it in?”

Wait until you change the ignition wires (on an older model) with the full knowledge that you have to get the new ones installed with the wires going to the right spark plugs... and then don't. I was alone in my garage when I did that but I looked around to make sure no one snuck in to see me screw that simple job up lol.