sparkplugs & wires,,, oh my,,

pepper · **Posted:** Thu Aug 04, 2005 7:11 pm

ok, has anyone used the 3 or 4 prong pugs on the KJ? and did you upgrade the wireing??

QuietOutdoorsman · **Posted:** Fri Aug 05, 2005 12:34 am

At least on the 3.7L, there are no plug wires. A coil on plug system is used (a seperate coil mounted onto each of the 6 plugs). As for the plugs......you can take your chances if you want. At 13 months and 14k miles I have not yet changed my plugs, though I am thinking of doing it soon. I have read many discussions on plug types, Splitfires....Bosch Platinum.....iridium plugs, the consensus is that no one has seen any definite improvement over the stock NGK in terms of power and only the slightest improvement in mpg if any. Bottom line is the NGK plugs are a high quality, long lasting plug and inexpensive.

Tradewindkj · **Posted:** Fri Aug 05, 2005 12:38 am

Ditto

The Staff · **Posted:** Fri Aug 05, 2005 12:53 am

Yep I am using the same type stock factory NGK plug and they seem to work great. I change them about every 25000 miles and it does help.

pepper · **Posted:** Fri Aug 05, 2005 5:27 am

cool, thanks guys

2003KJ · **Posted:** Fri Aug 05, 2005 10:12 am

Now on a coil on plug system like the KJ, is it best to replace the coils at the same time, or do they last much much longer than the plugs? Reason i'm asking is I'm comin up in 25K, and would like to do te tune up myself to save some money.

Bonehead · **Posted:** Fri Aug 05, 2005 1:26 pm

The coil on plug set up will hast a long time don't worry about changeing them.

Zeroack · **Joined:** Tue Jul 12, 2005 10:03 am **Posts:** 5

I'm thinking of picking up a set of bosch platniums. Any one tried them?

tanx

Zero

SavageUrge · **Posted:** Fri Aug 05, 2005 3:56 pm

I have used the Bosch Platinums with great success. I would recommend them to anyone. I've used them in my last 3 vehicles, and have never had a problem with them.

Zeroack · **Joined:** Tue Jul 12, 2005 10:03 am **Posts:** 5

I use to work a parts bench at the local napa and sell the heck out of them but that was 10 years ago. I didn't know if they would work well in KJ's.

tanx

Zero

Guest · **Posted:** Fri Aug 05, 2005 8:59 pm

I tried autolite on my first plug change and was not happy with the performance. Replaced them with the Bosch Platinum and it was a big difference in fuel mileage and gitty-up and go.

DaGuru · **Posted:** Mon Sep 05, 2005 3:31 pm

I'm about to install a set of Iridium plugs from Denso. If you do the same I noticed that AutoZone sold me IK16, but the Denso website recommended IK20. I've see other posts of people getting 1-2mpg increase. The theory behind them appears to be sound, smaller electrode equates better spark. I see this when welding all the time.

I'll be happy to post my findings after I install them.

Ok, just got them installed. The OEMs were pretty toasty. I need to do a fuel rail cleaning next. The tops of my cylinders looked nasty. :roll:

First impressions of the Denso plugs:: I can no longer fee the engine dragging when I let off the gas (that’s a plus) and it seems to have a bit more pep that it used to. Most likely any new plug would yield similar results. This is the first time I've changed them and I have just over 50K miles logged.

Admittedly, I have been lazy and just going by the onboard computer to figure my mpg. Yes, I know it's not accurate... :lol:

Anyway, I started logging everything three tanks ago. Interestingly enough, with crappy plugs I'm getting 19.23mpg in town.

I just started adding acetone to the tank, so between that, the new plugs, and when my P245 Revos arrive, I hope I can either maintain or do a little better.

Calvin56 · **Joined:** Fri Jul 08, 2005 1:59 am **Posts:** 345

I went over a study on the multiprong spark plugs when I was in college, and theoreticaly, they are a great idea. They start out making more power, but once they get a little gunk built up on them- think less than 500 miles, the conductivity changes for each of the prongs, and the electricity only ends up sparking accross one of the gaps, negating the advantage of the multi spark system. This was 6 years ago, so they might have changed since then...

winkelhawk · **Posted:** Wed Sep 07, 2005 5:14 pm

I had Bosch +4 plugs, worked well for 65,000 miles. I put in a set of Champions for the short term, I am going to be picking up the NGK or Denso iriduim plugs to try out. Would recommend the Bosh though.

Guyute1210 · **Posted:** Wed Sep 07, 2005 9:52 pm

DaGuru wrote:

I'm about to install a set of Iridium plugs from Denso. If you do the same I noticed that AutoZone sold me IK16, but the Denso website recommended IK20.

I found them for the 2004 3.7 V-6, but not the 2005. Will they fit mine the same?

habitTrail · **Joined:** Sat Jul 16, 2005 11:56 am **Posts:** 46

This place sells the stock plugs plus the high end ones. I'm running NGK Iridiums now and like them. Seems a slight improvement over stock. I previously tried the Denso Iridium but didn't like them as well. If I had it all to do over again, probably would just as well stick with stock and change them a little more often than recommended.
http://www.sparkplugs.com/default.asp
Just plug in your vehicle data and check it out.

DaGuru · **Posted:** Fri Sep 16, 2005 11:37 pm

Guyute1210 wrote:

I found them for the 2004 3.7 V-6, but not the 2005. Will they fit mine the same?

I would assume so, but to play it safe just go to the parts store and have them look up something more common like Bosch or NGK for the 2002 then have them do the same for your 2005. If the MFG part numbers are the same your good to go. :wink:

Good luck and plug away!

Oh, one last thing, AutoZone told me to gap them. Don't, they come pre-gapped from Denso. That’s why they have a plastic tube protecting them in the box. My only regret is that I haven’t bought a torque wrench yet. So, I went by feel. It’s probably not a good idea for anyone who doesn’t wretch very often. AutoZone can loan you a good one if you want it.

ltwgs · **Posted:** Sat Sep 17, 2005 1:26 am

Yes, the 3.7 has not changed, essentially.

I just hit 110k miles, and changed the plugs (among a LOT of other things). I get worse mileage now, and I'm using a fresh set of NGK plugs. A lot of jeepers endorse the NGK plugs, so it's up to you on that one. the BOSCH platinum plugs are great, IMHO.

No matter what, jeeps drink a lot of gas...

1calkid · **Posted:** Sat Sep 17, 2005 5:38 pm

When I changed my plugs, the dealer gave me a set of autolites. I was expecting to get a set up NGK's. I personally think they are wearing quicker then what the NGK's will, so I'm going to give them a try.

sparkplugs & wires,,, oh my,,

Who is online