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Autolite Platinum plugs for a cherokee 4.0HO

9

94HOCHEROKEE

NAXJA Forum User
Location
Colorado
I was wondering if anyone have run these plugs for their 4.0 HOs????:pirate1: I wanted to know if it runs bad, cause i've heard that only champions are the way to go. But I got a good deal on them, so here we are.

Any response is welcome. Thank you
 
Can't hurt to try.
 
I got a good deal on the platinums so I decided to go w/ them. The champions would have been like $3 less so I went w/ the platinum in hope of a better plug.....
 
I have those in my Jeep. They seem to work just fine to me. Better than the old ones because the old ones were burnt out and left at factory gap settings.
 
I have the "good" Jeep. Not a fan of 4 bangers, but yeah I think it's .035" for the 4.0L. Don't know about your model year, but on my '88, there is a sticker somewhere under the hood that tells you what to gap them to and if I remember right, I think it said .035".
 
i have tired platinum plug in a few of my 4.0 and they hated it! copper is the way to go in the 4.0 I use champion and will be trying the NGK R now since I cant find the champion truck series any where anymore.
 
i bought my jeep with bosch platinum 2s in it.. didnt seem to run right. just changed em to champions, seems to run and idle way better. and the boschs didnt look that old..
 
Making me worried since i've heard that copper is the best...... I guess I will throw them in and see how it goes. I will report back later 2day and let you know how it goes..........
 
Best luck with cheap plugs in my 99. Had the Bosch Platinums once for about 200miles. Never ran quite right, just something felt wrong and it wouldnt idle as smoothly.
 
One thing I've noticed when crossing plugs to a different or "novelty" brand is that the heat ranges may not be right. For example, the oddball 4-v whateevers may only come in 4 different heat ranges versus the generic champions which have 7 heat ranges. The application guide will always give you a colder plug if there is no exact match as its safer (it will tend to foul instead of detonate). Thus it's sometimes hit or miss (pun intended) whether the other plug type works well for you.
 
You need to recognize that there are one, 2, and 4 ground pin style platinums, and there are copper core, non copper core, resistor, non-resistor, with and with out platimum coated tips. I found about 30 different plugs in the AZ data base of plugs available for 4.0s recently!

I have used Autolight and Bosch single ground resistor platinums with no problems in the older renix 4.0 engines. My 89 has the Autolight single platinums stock heat range (or what ever the stock crossover is) and they run great. I hear the 2 and 4 ground platinum Bosch does not work properly in 4.0s.

5-90 runs autolight single platinums too in renix, IIRC.

Regarding heat range, # of ground electrodes, etc., if you want to talk plugs, you need to get down to the exact part number you are recommending, or saying works, doesn't work.
 
I am finally getting back to you guys after putting them in.

I found out that I had bosch supers that my dad must have put in, but now that I have the Autolite P/N#AP925's in there it seems like it runs exactly the same...... The only difference I noticed was it kicked over sooner after starting it once then letting it sit for like an hour.

When I pulled my old plugs the bosch "supers", they were showing signs of white crud on them. I looked it up in my haynes and it was from engine overheating since I had overheating probs while they were in there, I figured thats what its from.

I was wondering if your supposed to use the gaskets they come w/?? i saw my dad used them last time so I put the new ones in. How tight are you supposed to tighten them down, cause i read on the box for a gasket its 1/4-1/2 turn after hand tight and gasketless it 1/6 of a turn after tight. Any input is appreciated
 
1990 FSM torque spec for spark plugs 27 ftlbs.
 
Mr. joe p thank you very much. Maybe some day soon I will end up buying one of those fancy FSMs....... good stuff
Does it matter that I have the H.O 4.0???
Thanks again
 
94HOCHEROKEE said:
Mr. joe p thank you very much. Maybe some day soon I will end up buying one of those fancy FSMs....... good stuff
Does it matter that I have the H.O 4.0???
Thanks again
Click to expand...

It might, maybe someone else has the later FSM.

When you get ready to buy one, http://www.autobooksbishko.com/index.html has LICENSED reprints and CDs. You can find manuals on ebay, but don't waste your money on the unlicensed junk (which most of the CDs are) and stick with original FSMs.
 
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