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-   -   Spark plug question TJ (http://www.wranglerforum.com/f210/spark-plug-question-tj-55934.html)

cru9 07-21-2010 04:58 PM

Spark plug question TJ
 
Is anybody running the Bosch Platinum Plus 4
In a TJ 4.0 liter 6cyl?

Do they make a difference?
Worth the extra few $?

Schmo 07-21-2010 05:16 PM

Quote:

Originally Posted by cru9 (Post 696573)
Is anybody running the Bosch Platinum Plus 4
In a TJ 4.0 liter 6cyl?

Do they make a difference?
Worth the extra few $?


Don't do it! They make a difference alright . . . they make your Jeep run like crap. Stick with either the stock Champions, NGKs, or Autolites . . . and make sure you get the right ones for your Jeep . . . don't trust what the guy at the parts counter tells you is the right plug and don't trust the computer at your local auto parts supply place either . . . and even if you order the correct part number, double check to make sure the monkeys actually ordered the correct plug that you told them to order . . . can you tell I've been thru this before?!? I put the Bosch Platinum plugs in my Jeep after 3 different parts supply places didn't have the stock plugs and suggested these . . . Bosch must pay them under the table or bring free donuts in when they drop off the merch cuz the monkeys at the supply place sure love to push their plugs. They totally sucked and I took them out and went with NGKs after a short time. My first clue that I made the wrong decision was when I told my mechanic buddy that I put in new plugs and he said . . . "you didn't put Bosch plugs in it did you" . . . then I see on the forums how all the Jeep guys bash on the plugs . . . sure enough the Jeep started running rough after a short time. Bosch plugs went in the trash and I got some NGKs in there.

rrich 07-21-2010 05:38 PM

Bosch === Hitler's revenge!

JDsDream 07-21-2010 06:22 PM

Bosch is great and I wouldn't put anything else IN MY BMW! But for my Jeep, NO WAY would I use them. Go to the stealership and pick up the stock NGK's.

Jerry Bransford 07-21-2010 06:43 PM

Yep as advised above, avoid the Plus 2 and Plus 4 plugs in the 2.5L or 4.0L engine. For some reason, probably heat-range related, they don't run well later after being installed.

What year 4.0L engine do you have, does it still have a distributor or is it one of the newer distributorless engines?

jeepjones 07-21-2010 06:48 PM

What SCHMO said.

doclouie 07-21-2010 07:11 PM

The PO had them in the Jeep when I bought it and it ran rough. Once I put in the Champion plugs it ran so much smoother. I have had too many problems with Bosch plugs.

cru9 07-21-2010 07:25 PM

Quote:

Originally Posted by Jerry Bransford (Post 696680)
Yep as advised above, avoid the Plus 2 and Plus 4 plugs in the 2.5L or 4.0L engine. For some reason, probably heat-range related, they don't run well later after being installed.

What year 4.0L engine do you have, does it still have a distributor or is it one of the newer distributorless engines?

2004 4.0l NO distributor

cru9 07-21-2010 07:26 PM

2003 sorry

pokey 07-21-2010 07:34 PM

I think our simple 4.0's like simple plugs. I'm not sure about the distributorless motors ( 2000 and later), but my '99 seems to like the Champion 4412 truck plugs. The ones I pulled out were the plain Autolite 985's which were running fine when I changed them. The autolites are made in China, which didn't seem right too me so I went with the champions.

Jerry Bransford 07-21-2010 07:41 PM

Quote:

Originally Posted by cru9 (Post 696731)
2003

Good to know because newer distributorless engines like yours are very particular about the plugs they run on. One very good plug that works well is the double-tipped platinum Autolite APP985, just don't install the single-tipped platinum AP985 which will cause problems. Champion's 7034 is a good choice too and like Autolite's APP985, is a double-tipped platinum plug. Either will do well for at least 90K if not 100K miles.

The conventional non-platinum Autolite 985 or Champion 4412 (discontinued I believe) plugs will work fine too but they only last 25-30K miles at the most.

Make sure to never install a single-tipped platinum plug. Single-tipped just means that the platinum coating is on only one side of the gap which will cause problems for newer distributorless engines. Such engines require either double-tipped (platinum on both sides of the gap) or conventional plugs.

drivebytruckerz 07-21-2010 07:45 PM

Just like it's love of 87 octane (simple) gasoline.. the Chrysler 4.0, as stated by pokey, are simple engines and are made to be maintained simply with simple, common parts. Just stick with the basics.

cru9 07-21-2010 07:45 PM

Quote:

Originally Posted by Jerry Bransford (Post 696751)
Good to know because newer distributorless engines like yours are very particular about the plugs they run on. One very good plug that works well is the double-tipped platinum Autolite APP985, just don't install the single-tipped platinum AP985 which will cause problems. Champion's 7034 is a good choice too and like Autolite's APP985, is a double-tipped platinum plug. Either will do well for at least 90K if not 100K miles.

The conventional non-platinum Autolite 985 or Champion 4412 (discontinued I believe) plugs will work fine too but they only last 25-30K miles at the most.

Make sure to never install a single-tipped platinum plug. Single-tipped just means that the platinum coating is on only one side of the gap which will cause problems for newer distributorless engines. Such engines require either double-tipped (platinum on both sides of the gap) or conventional plugs.


If you were going to buy some tomorrow for my Jeep what would you go after..I need them but i have time to go track down the correct plug.

Kate 07-21-2010 07:46 PM

Yea, everything i have ever read says to just use the factory NGK plug in it.
They're cheap too.

Everything I have seen on other plugs says it's BAD JUJU!

Jerry Bransford 07-21-2010 08:00 PM

Quote:

Originally Posted by cru9 (Post 696762)
If you were going to buy some tomorrow for my Jeep what would you go after..I need them but i have time to go track down the correct plug.

Autolite APP985. If they don't have that, I'd go for the Champion 7034. They should be pre-gapped to the correct .035 but double check them. :)

cru9 07-21-2010 08:09 PM

Thanks I will get some tomorrow

frazier 07-21-2010 09:25 PM

Wish I had read this earlier. I just installed Bosch Plats in my 2005 this weekend, but so far it seems to be running fine. Should I replace them?

Jerry Bransford 07-21-2010 09:45 PM

Quote:

Originally Posted by frazier (Post 696948)
Wish I had read this earlier. I just installed Bosch Plats in my 2005 this weekend, but so far it seems to be running fine. Should I replace them?

If they are not Plus 4 or Plus 2 plugs which are both bad, they may or may not be ok. Do you know if what you installed are single or double tipped platinum? If you don't know, what model # plug did you install?

cswusc_03X 07-22-2010 03:45 PM

I've got a 2003 as well.

I went with Champion RC12ECC .035 Gap

frazier 07-22-2010 09:00 PM

Quote:

Originally Posted by Jerry Bransford (Post 696965)
If they are not Plus 4 or Plus 2 plugs which are both bad, they may or may not be ok. Do you know if what you installed are single or double tipped platinum? If you don't know, what model # plug did you install?

They are the Bosch Platinum Plus plugs, part number 4003, does that help? Nothing on the box mentions single or double tipped paltinum.

Jerry Bransford 07-23-2010 01:11 AM

Quote:

Originally Posted by frazier (Post 698060)
They are the Bosch Platinum Plus plugs, part number 4003, does that help? Nothing on the box mentions single or double tipped paltinum.

From the description at Bosch Spark Plugs: Automotive spark plugs, Motorcycle sparkplugs, high performance plugs the 4003 is a single-tipped platinum plug with platinum only on its center electrode. That's the wrong type of plug for your newer TJ and while it may run ok for now, single-tipped platinum plugs inevitably cause problems in the newer distributorless 4.0L engines later on. For the newer distributorless 4.0L engine which uses what they call a "waste-spark" ignition system, both sides of the spark plug gap must be made from the same material. :)

frazier 07-31-2010 05:21 PM

Autolite plugs
 
Thanks Jerry, I removed the Bosch plugs and went with Autolite 985, just plain old plugs and I can't belive the difference it made.

Thanks again for the info!

Frazier:D

cru9 08-01-2010 06:58 AM

Quote:

Originally Posted by frazier (Post 707782)
Thanks Jerry, I removed the Bosch plugs and went with Autolite 985, just plain old plugs and I can't belive the difference it made.

Thanks again for the info!

Frazier:D

Did you do the plain jane AP985?

Big O 08-02-2010 11:30 AM

Installed the Platinum Ir Fusion a few weeks ago and the engine is running smooth. Gained 1 MPG. Using Mid-grade fuel.

motorking 08-09-2010 08:24 AM

What is the best plug for a DIS 4.0 Jeep?
 
Quote:

Originally Posted by Big O (Post 709379)
Installed the Platinum Ir Fusion a few weeks ago and the engine is running smooth. Gained 1 MPG. Using Mid-grade fuel.

Use the Autolite XP985 dudes! This is a iridium fine wire center electrode with a pltinum button on the side wire. less volatge to fire, bigger flame kernal and 100k durability. You will notice a difference in the way your Jeep runs. :wavey:

pokey 08-09-2010 11:17 AM

Quote:

Originally Posted by motorking (Post 717161)
Use the Autolite XP985 dudes! This is a iridium fine wire center electrode with a pltinum button on the side wire. less volatge to fire, bigger flame kernal and 100k durability. You will notice a difference in the way your Jeep runs. :wavey:

It works good in spaceships too....:zap:

Rykugb 08-09-2010 11:38 AM

Quote:

Originally Posted by Big O (Post 709379)
Installed the Platinum Ir Fusion a few weeks ago and the engine is running smooth. Gained 1 MPG. Using Mid-grade fuel.

F!!! I have been using the same set up for over 2000 miles with a steady performance loss since. I thought the coil packs were starting to go because of start off hesitation. I guess I have a project tomorrow.......

Jerry Bransford 08-09-2010 12:34 PM

Quote:

Originally Posted by Big O (Post 709379)
Using Mid-grade fuel.

There is zero... nada, none whatsoever, benefit to using a mid-grade octane fuel in our TJ engines. Using any octane higher than 87 is just costing you more $$$ without any benefit whatsoever. 89 doesn't provide any more power or cleaning additives than 87 does. The only thing octane does is to slow how quickly the fuel ignites and to prevent premature compression-induced ignition in high compression engines... which the 4.0L engine is not. Really. :)

P.S. Here's a slightly longer explanation of why running a higher octane fuel than the engine was designed to require doesn't help... http://www.wranglerforum.com/f5/gas-...tml#post715509

pokey 08-09-2010 02:44 PM

Quote:

Originally Posted by cru9 (Post 708197)
Did you do the plain jane AP985?

The plain jane is the autolite 985 (no letters in front). The P in AP stands for platinum. The 985's are copper. Cost about a buck each and the 4.0's love 'em. You should change them at 25 or 30K which to me is no big deal because there's something about changing my plugs that I enjoy.

The platinums will last a lot longer, but like I said, the 4.0's love copper plugs. Another good copper plug (the one I use) is the Champion 4412 truck plug. Kragen/O'reilly will tell you they are discontinued but they are not. Call around. Carquest has them. It was explained to me they call them truck plugs because they're a heavy duty plug. Cost more than a buck, but great plugs.

Wrangler97-EEK 08-09-2010 04:51 PM

You say nothin more than 87 octane? My 97 is not adjustable on timing and idles at 17 degrees btdc. You can tell the difference between 87 and 92.


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