Spark plug replacement

[Dcook65]

Maybe I dumb question for some. I am fairly mechanical. That said, are there any pitfalls to watch out for when removing coil rail and replacing spark plugs on a 2001 TJ 4.0?

 

[Chris]

Nope, it's probably one of the easier things you can do on a TJ!

 

[mgroeger]

 

[mgroeger]

Nope, it's probably one of the easier things you can do on a TJ!

Chris aren't you glad you showed me how to use GIPHY? LOL!!!

 

[Chris]

Chris aren't you glad you showed me how to use GIPHY? LOL!!!

I was about to say, looks like someone is enjoying it

Way better than an emoji, that's for sure!

 

[mgroeger]

I was about to say, looks like someone is enjoying it

Way better than an emoji, that's for sure!

LOL. Hey, you can't keep using that gif

 

[Jerry Bransford]

Just be wary of the spark plugs you choose for your newer 4.0L engine which is fussy about what it will run well on. Three known good plugs plugs include the platinum-tipped Autolite APP-985 and Champion 7412, both of which will perform well for 100k miles. Those two plugs are "double tipped" platinums which means the platinum coating is on both sides of the gap. Autolite's iridium tipped XP-985 will perform well for 200k miles.

Make sure NOT to install single-tipped platinum plugs where the platinum is only on one side of the gap. Champion's 3034 and Autolite's AP-985 are single-tipped platinum plugs and they'll eventually start causing hard to diagnose rough idles, misfires, etc.

Some guide books are incorrect when they recommend single-tipped platinum plugs for newer 4.0L engines like yours so be wary... not everything listed will work properly. Jeep had to issue a TSB (tech service bulletin) to remove single-tipped platinum plugs when a customer brings in a newer Jeep with misfires and rough idles.

 

[AndyG]

I carefully gapped my new plugs recently installed them and I was really surprised at how much better the engine performed and my TJ does not have a lot of miles on it.

if I got my hands on another one tomorrow doing plugs would be one of the first things I would do.

 

[mgroeger]

I carefully gapped my new plugs recently installed them and I was really surprised at how much better the engine performed and my TJ does not have a lot of miles on it.

if I got my hands on another one tomorrow doing plugs would be one of the first things I would do.

What plugs did you get?

 

[AndyG]

Champion #7034 ,they are double platinum .

 

[Jerry Bransford]

Champion #7034 ,they are double platinum .

So far as I can tell is the 7034 was replaced by the 7412 last year. I used to regularly recommend the 7034 but it looks like it's only available as long as stocks last. Apparently the 7412 is what you want now if you like Champion and need a double-tipped platinum.

 

[AndyG]

So far as I can tell is the 7034 was replaced by the 7412 last year. I used to regularly recommend the 7034 but it looks like it's only available as long as stocks last. Apparently the 7412 is what you want now if you like Champion and need a double-tipped platinum.

I think I was after the other plug Jerry recommended , they didn't have stock, and I bought the Champions.

Really surprised me how it smoothed out the idle and my acceleration improved .

 

[Stockli]

How easy is it to strip the threads on the tj?

I did mine and I got them pretty tight but I didn’t like the way they felt. No hard lockdown like other motors I noticed.

I threaded then in by hand nice and straight but would have liked a more positive lockdown.

 

[AndyG]

I couldn't answer ..mine snugged right up ..I just made sure I felt the crush washer seat .

A good trick on starting plugs deep in is use a short tube or vacuum hose slipped over the plug to start it ...you 'll never cross thread one that way .