just wondering are the plugs and wires you get from autozone, orileys ...... are they just as good as any or should i opt for something different.????
Are spark plugs and wires from AutoZone or O'Reilly's any good?
- Thread starter Eddie Greenlee
- Start date
WIring first... there is a lot of really bad quality "junk" out there they're calling ignition wiring sets. Especially the ones pushing "low resistance", "high performance" etc. Such statements sound good to someone who isn't up on how ignition wiring has to be designed to minimize static, computer problems, radio interference, but they're very misleading. Resistance is actually added at extra cost to eliminate the static and other problems low-resistance ignition wiring causes. Low resistance wiring actually costs less to manufacture so it's not like it's a better wire even if it sounds better. And surprisingly, low-resistance wiring doesn't really provide a higher voltage spark as would make sense. True! That's due to the very small amount of current that passes through the ignition wiring which means the wiring drops very little voltage. Ohm's Law and all that.
There are some good quality wiring sets but they're hard to find because there are so many cheap wiring sets that are pushed hard by some auto parts stores.
The very best ignition wiring you can get, as well as the best performing, is actually the OE Mopar wiring. I'd look for that on websites like www.wermopar.com since it is worth the extra effort and cost to find.
Spark plug-wise, early TJ 4.0L engines aren't especially fussy about which spark plugs they'll run well on. About the only plugs I won't recommend include Bosch (lack of appropriate heat ranges), E-3, and Splitfire... the last two being "junk technology". Three very good plugs include the Autolite AP985, Champion 3034, and Autolite XP-985. The first two are platinum plugs good for about 100k miles, the last one is iridium which is good for probably no less than 200k miles. NGK is good too, I just don't know those part numbers off the top of my head.
If it were me, I'd go for the Autolite XP985 iridium-tipped plugs and Mopar ignition wiring set.
This ignition wiring set right here... http://www.moparpartsdeals.com/oe-m...XiBQIem1jOF0wwGOtzMQhV-v3etKK8QbyQaAnca8P8HAQ
There are some good quality wiring sets but they're hard to find because there are so many cheap wiring sets that are pushed hard by some auto parts stores.
The very best ignition wiring you can get, as well as the best performing, is actually the OE Mopar wiring. I'd look for that on websites like www.wermopar.com since it is worth the extra effort and cost to find.
Spark plug-wise, early TJ 4.0L engines aren't especially fussy about which spark plugs they'll run well on. About the only plugs I won't recommend include Bosch (lack of appropriate heat ranges), E-3, and Splitfire... the last two being "junk technology". Three very good plugs include the Autolite AP985, Champion 3034, and Autolite XP-985. The first two are platinum plugs good for about 100k miles, the last one is iridium which is good for probably no less than 200k miles. NGK is good too, I just don't know those part numbers off the top of my head.
If it were me, I'd go for the Autolite XP985 iridium-tipped plugs and Mopar ignition wiring set.
This ignition wiring set right here... http://www.moparpartsdeals.com/oe-m...XiBQIem1jOF0wwGOtzMQhV-v3etKK8QbyQaAnca8P8HAQ
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OP
Well i had to buy a set of wires because i broke one getting it off the spark plug so i bought a set of Duralast Gold Ignition wires. I hope i didnt make to big of a mistake.
also the guy sold me some Champion 412 . there is also a RC12LYC number on the box. that may be the stock # I may take them back and get the Champion 3034. I think Champion is closest to the OEM plug ???
also the guy sold me some Champion 412 . there is also a RC12LYC number on the box. that may be the stock # I may take them back and get the Champion 3034. I think Champion is closest to the OEM plug ???
OP
OP
Good to hear! Plugs and wires are something that's so simple to change, but can make such a big difference!
The link for the wires lists them as discontinued. Wermopar doesn’t seem to list them either. Assuming they are not available could you recommend a specific aftermarket alternative. Thanks
Found these at summit racing.
https://www.summitracing.com/parts/mop-05017059ab/overview/
Their description claims they are as close as possible to oem?
https://www.summitracing.com/parts/mop-05017059ab/overview/
Their description claims they are as close as possible to oem?
Daniel.Lee
Member
Did you ever buy these and try them out? If so, how do they perform? I'm getting a cylinder 1 misfire... replaced spark plug and problem persists.
Daniel.Lee
Member
1998 4.0L
I replaced the spark plug because that's what was easiest and cheapest.
I'm thinking about swapping injector 1 out with an injector from one of the problem free cylinders, clearing the code, and seeing if the misfire moves. However, I've not done this before so I'll have to study up and clear a Saturday for it.
Also, I cleared the code with my OBDII device to see if it was an anomaly misfire and I drove free of a check engine light for at least 50 miles and then suddenly the check engine light came back on throwing the same cylinder 1 misfire code. It's this intermittent behavior that leads me to believe it may be the ignition wiring shorting out.
To add to Jerry's recommendation of Autolite plugs, they seemed to always hold up the best during my drag racing days...even to a 250 shot of nitrous...other plugs would last a quarter of the Autolite's.
Ignition wires can go bad but they rarely short out. Some auto parts stores have individual replacement ignition wires. Maybe bring the #1 ignition wire to the local Napa store to see if they have one with a close enough length.
Swapping the #1 injector with one of the others is a good troubleshooting method.
Is the distributor cap and rotor in good condition?
Cole
TJ Enthusiast
This may open a can of worms, but I have no idea when the PO previously put in new plugs and wires. But about half the time I start my jeep it will turn over a bit, then I have to let off the key, then turn the key again and it fires right up. Other times, it starts on the first turn of the key.
Easy as plugs and wires?
Easy as plugs and wires?
Daniel.Lee
Member
So I swapped injector 1 with 6 this past weekend, cleared the code, and sure enough cylinder 1 misfire came back. I think I’ll take your advice on the ignition wire and see if I can fix the issue with that.
How do you check to see if the distributor cap and rotor are good?
Thanks,
Dan
Take 'em off the distributor and look at their contacts. If either is bad look for a set with brass contacts which last longer than aluminum does. Low end auto parts stores like Autozone are less likely to carry the better quality versions with brass contacts. I'd head to a NAPA store if you have one in your area.
Daniel.Lee
Member
Jerry,
I’ve ordered a new cap with brass contacts and rotor from Quadratec... still waiting on the delivery. Apparently they’re out of stock. Once it gets here I’ll swap it out and see if that addresses the issue. Thanks for the advice!
Daniel.Lee
Member
So I replaced the distributor cap and rotor, cleared the code, and the cylinder 1 misfire returned. I'm scratching my head here. A buddy of mine has an oscilloscope so I think I'll borrow it and look at the waveform coming out of the fuel injector wires. I'm hoping this'll clue me in on what's going on.
I kinda doubt you'll see anything unusual on the fuel injector pulse with the scope though it'd be interesting. Should be nothing but a clean low frequency square wave. I'd next swap the #1 injector with one of the others and see if the misfire follows the #1 injector to the new location or if the misfire remains at the #1 location.
Early 97-98 4.0L engines had misfire problems caused by a bad (weak) set of valve springs the factory received. Replacing the springs was the fix for that. The same p/n valve springs are used, the bad valve springs were removed from the system.