Plugs?

What are you guys running for aftermarket plugs? I was looking at the Platinum T-4's with the 4 electrodes they look pretty dependable and high performance. I was also Looking at some performance wires as well. What can you recommend as far as plug wires for this setup? WHat should my stock plugs look like as well?

I run the Bosch Plat +2's. I can't see how there would be any benefit to having 4 posts instead of 2. They work great and actually helped out my emissions significantly.
For wires, I went with the Bosch Premiums avail at Autozone.
I replaced plugs/wires at the same time so I don't know how much benefit was caused by each product, but the combo runs good and smooth.

Don't get fancy, save your cash and use plain old Champions. I have personally used the P+4's (once) and although they will last a long time, the only immediate increase I noticed was that the platinums cost 3x what the Champs do!
I'm assuming that you have the 4.0 which is a kick-ass truck motor that has no need for "performance" plugs/wires to do the job it was designed for. The stock ignition system is more than up to the task and unless you're into $$$$$$$ engine mods that require more spark, it's just another exercise in $pending.
I got that creepy feeling that this could turn into one of those "Regular vs. Premium fuel" type of threads.
J.R.

Skip the platinums. Use either Champion truck plugs or standard NGKs. As for wires, the best performance wire if money is no object is a set of Magne-Cores, but by far the best bang for the buck is Mopar Performance Wires, available through any Mopar dealer from the performance catalog. If you need the part number to fit a '90 I can look it up for you.

I agree with Mark.....

Bosch Platinums have caused misfiring problems in a variety of vehicles of all makes. Why, no one will say. Whatever the deal it tells me something is not quite right with them. Auto makers have been scrambling to reprogram computers to accommodate the misfiring trouble codes set in some vehicles. I personally have had serious problems with them in my own vehicles in the distant past and with customer's vehicles along the way.

So i'd say stay away from them. Use cheapo stock Champions and side-gap them if you want to unshroud the spark a little. Spend your $$ in other areas. These non-crossflow 4.0's were never meant to be rev monsters (although they may surprise you) so high revability is pretty much a non-issue. Maybe the Bosch might work okay in these engines, but nothing seems to be able to outperform the plain low cost Champions.

My experience has been that Autolite and NGK build very good products...I use standard NGK's in my dragbikes. I have found reliable performance to 12,000 RPM. In my Jeep, I use either depending on availability.

I just replaced the bosch plugs that were in the 4.2L YJ's motor with autolite, nobody had Champions in stock They seem to be OK but it's only been about 3 days, we'll see next week when I pull them and have a look, by that time I should also have the bbd rebuild kit for it.
On my 98XJ with 180,000mi I only run the dealer supplied OEM champions. I also only run the dealer supplied OEM cap, rotor and wires as well as the serpentine belt [which is still original, but I carry a spare under the back seat ] I may pickup a set of the HP Mopars this week, depends on if I get any service calls out that way. The last part number I had for wires was P4876436, around $46 or so.
One curiousity, one plug, #1 front of engine was bright red, could not find that color in the chiltons plug pictures and no, never ran exxon gas in it either

Red?

Hummmm. Never have seen a red one myself but have heard that as a result of a certain fuel additive...Exxon? Whatever the case does sound like that one cyl is experiencing some type of a operating difference. Leaky injector?? Have found autolites in about everything i have worked on along the way. Think there must be some kind of a 'kick-back' going on to shops to use them!! That $46 is not bad for high perf wires...that was even hi perf??

I've run Autolite Platinums, Bosch Platinums, and Bosch Platinum +4's. The +4's ran smoother, but there was no increase in performance or gas mileage. The other two ran just as reliably and worked just as well. About the red plug....do you have regular green antifreeze or an orange colored antifreeze? I had a car once with a coolant leak through a crack in the head right next to the spark plug and it would color it slightly green. Just something to check.

The red plug tip is in a YJ 4.2 with a carter BBD 2bbl carb. I almost have the feeling that the cylinder was not firing. But it's my sons and I only noticed it when it died about two weeks ago when the ecu went belly up. I just happened to pull that first plug to see if it was getting spark. The plugs that were in it were bosch, now I replaced them with autolites but the venturies are dripping again at idle. I'm going to drill them out tomorrow and get rid of that funky crimped taper they have. I also need to find a welders supply and pick up a set of those gauges for cleaning out the tips of the varnish that builds up in them. Carb cleaner, literally, is not cutting the varnish. I also want to run a compression check on that cylinder and make sure the valves are working correctly. Man, these straight sixes are just so much easier to work on than all the v6 and v8's I've had. I'd love to be able to afford a holley FI setup for it, among alot of other things. That price is for the big HP wires, I think they were actually cheaper than the stock OEM's. Might try the local dodge dealer down the street and see if they can order them, save a trip out of the way to the jeep dealer, I don't have one nearby, closest is 30 mi away.

don't waste your time or money on the bosch plugs. I tried them and my motor was misfiring so bad I did not kow if my heep was going to make it home or not. Then I got some champion truck plugs and everything was cool. Later, Eric

RichP said:

I'd love to be able to afford a holley FI setup for it, among alot of other things.

Click to expand...

Rich, I seem to remember that Chrysler actually made a FI conversion kit for the 4.2 (think I saw it on "Trucks") -- new, I think it ran about $1200, but I can't help thinking that somewhere out there there's a junkyard that has a 4.2 with this conversion waiting to be stripped.

If nothing else, it might occupy a couple hours of the son's time having him call around to the local savlage outfits.

Rob

P.S. I feel your pain with the carb - my 84 Omni is finally coming home after nearly 7 months in the shop for carb work to pass emissions. You think that Carter is bad? It's got nothing on the Holley 5200 series that Chrysler put on the K- and L- cars with the 2.2l powerplant. The guy I took it to sent it to a friend of his that has a smog test setup (NJ, of course), and he got it through finally, although in my mechanic's words, "scary stuff" had to be done. Still, it could be worse - you could have one of the supposedly infamous Toyota "Variable Venturi" Carbs - which sounds even scarier than either of ours.

For what it's worth, when I was working on installing TJ flares on my XJ at Ed's place he had someone else stop by with a vapor lock problem. The 4.2 engine had the MOPAR fuel injection conversion setup and supposedly that is a common problem with those....

Kejtar

I agree that the Champion plugs are the way to go....I see no sense in wasting money on the high-priced multi electrode plugs. But that's me! Over the years I've tried many different plugs (platinums, NGKs, Champion truck plugs, OEM Champions, amony others) and saw no benefit with the high priced brands.

I hear from a trusted employee at my local Jeep dealership that the OEM Champions are NOT the same as the Champions sold by AutoZone, etc. Regardless, the OEM Champions have worked every bit as well, if not better, than any other plug I've used. YMMV.

Tom