Jeep 4.0 spark plugs?

[HawkeyeScott]

Getting ready to do a tune-up on '01 Cherokee. Any suggestions on best spark plugs for this motor? I had a mechanic tune another Jeep for me a few years ago, also with the 4.0 and he said he was a big fan of Motorcraft plugs.

I welcome your thoughts on best plugs, wires, cap etc. Thanks in advance.

 

[Quest]

I'm a big fan of NGK products, so naturally I would go with NGK plugs and spark plug cables.

As for D-cap and rotor, you simply can't go wrong with original factory products (not too much of a big fan of aftermarket d-caps and rotors, esp. for applications such as Honda, Toyota or Mazda).



Q.

 

[Eddie]

I had excellent service with Bosch Super plugs. NOT the plats.

 

[Mitch]

I pulled NGK's out of mine and put the same kind back in. I thought '01 and later 4.0's were distributer less?Maybe just the TJ's are?

 

[Studebaker]

If you go to the Jeep forums you will find they often recommend Champion truck plugs.

 

[MNgopher]

Champion Truck plugs are the standard answer for most 4.0's (and what I am running in my '88 Cherokee), but I believe NGK's were recommemded for the latest of the 40.0's in the Cherokees.

 

[Brett Miller]

I put Bosch Super plugs in my '01 14,000 miles ago. They are working well. I would suspect any good copper plug will work in a 4.0.

 

[gtx510]

I'd rec'd a Accel or Napa (Ecklin) dist cap/rotor since they use brass contacts, but didn't the Cherokee go to direct-fire ignition in 2000?
Accel makes some nice wires if it still uses those.

http://www.teamcherokee.com/Tune-Up_Parts/index.html
says NGK ZFR5N is the stock plug (projected tip)

http://www.sparkplugs.com/results_cross.asp?pid=ZFR5N
(put your cursor over the light blue part for info)


http://www.sparkplugs.com/results_app.asp?aaia=1373666
If you want to go more than 15-20k on a set of plugs try some iridium plugs (not platinium). Normally I'd rec'd NGK but they don't list a projected tip Ir plug, only Autolite does, p/n XP985. They're $4.82 each @ rockauto.com


wait, I found a NGK Ir plug here, but the gap is 0.044" instead of 0.035". Your ignition should be able to handle that fine or close the gap a pinch.
http://www.sparkplugs.com/results_cross.asp?pid=ZFR5FIX-11

 

[MarkC]

I've used almost every kind of plug in my 96, and my favorites are NGK and Champion Truck Plugs.

 

[jg1]

91 yj 4.0 5sp, I've used the NGK (7252), the ceramic on all 6 cracked on me < 10K. Should note I use a msd coil, magnecor wires, accel distributor and rotor.

Been using run of the mill autolites no issues.

take care.

 

[Gary Allan]

Quote:

---

I thought '01 and later 4.0's were distributer less? Maybe just the TJ's are?

---

No, you're right. He's got 3 coils in a "serviceable only by replacement" configuration. If he gets a misfire code and plugs don't solve it, he's buying a $200 unit (last I heard). IIRC, the wires are integrated with the coil packs (not sure). They just route the two wires per jug to the proper cylinder(s) for the waste spark.

I used Autolite plugs last time. I wanted to try Champion Truck plugs ..but no one stocks them. It appears my fatigue time on standard plugs is around 30k. I've used Plus+4's without complaint ..but they're not even the right length (one size fits too many-at least at that time). The OEM is WAY longer. I don't even know how they even reach into the combustion chamber. I was so freaked with the differences between the +4's that I pulled out ..and the Autolites that I was putting in ..that I went back to check that the Autolites were indeed the correct part.

 

[Challenger71]

Quote:

---

Quote:

---

I thought '01 and later 4.0's were distributer less? Maybe just the TJ's are?

---

No, you're right. He's got 3 coils in a "serviceable only by replacement" configuration. If he gets a misfire code and plugs don't solve it, he's buying a $200 unit (last I heard). IIRC, the wires are integrated with the coil packs (not sure). They just route the two wires per jug to the proper cylinder(s) for the waste spark.

---

Gary, your right on the money..wires are integrated with the pack and coil pack does have banks of three with two plugs per bank. I've seen prices as low as $160 for the pack itself but 200 is average. Personally i use autolite iridiums and the XJ loves it.

 

[Chris142]

Champion truck plug #4412 I believe. Do not run a platinum plug in this engine. It's a waste spark system and the platnum plugs make it miss and throw codes.

 

[Brandon]

I used Champion Truck plugs and Bosch Super plugs....both copper and both performed well. I would go with Bosch Super since they are only like a $1.00 a piece and work just as good if not better than the Champion Truck plugs. That reminds me...it's been a while since I last changed mine so it's time to check.

 

[D189379]

My 2000 has bosch platinums and runs fine. I don't think the 4.0 cares much what you use. Might as well save a few bucks.