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3.6 engine and 87 octane a no-no

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Petey

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How loud is the pinging that everyone is hearing? Hear it with windows up? Windows down? Have to stick your head out the window to hear it?

87 octane ... hear it all the time, and like another poster said, with windows up and music playing its not obvious .. however what is obvious is is how the torque becomes shaky.
89 octane .. hear it. but rarely ... its a lot less pronounced... torque becomes smoother
92 octane.. the best choice, unfortunate for me, it costs more ..@ this level it becomes almost none existent ... engine has smoother acceleration.
Running the ac compressor makes the problem more pronounced (more load)
Its like taking a hammer and smacking the piston with it ... most people are fine with that or have no clue it happening .
For the greater part I haven't heard it on the other JL's so I would say this applies for a select few of us
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AussieJLOverland

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In Australia our octane level is calculated differently which gives us 91, 95 or 98 octane fuel ratings. Our jeeps are recommended to run on our 91 octane which I believe is equivalent to the US 87. Our JL Overland Unlimited was bought new in 2019 & I definitely noticed the rattling/ping but only at low speeds/revs & only after the engine was well warmed up. It seems to be especially prominent & worse when 4 wheeling at low speeds & climbing. I went looking for threads on this issue as it seemed to be getting worse & tried the highest octane fuel to remedy the problem. My observations after a couple of months using our 98 octane fuel from BP are - pinging/rattle is very much reduced with normal street driving & barely noticeable but when offroading in 4wd it is still very prominent & at it's loudest & worse. Fuel economy appears to be a little improved but marginal & not enough to make a big song & dance about (maybe half a litre per hundred kilometers better) but it does seem to run a little smoother & have slightly more get up & go & a bit more responsive to pedal input but again nothing to write home about by itself but all combined it does add up to an improvement overall with power, economy & smoother running even if it is only marginal, but using the high octane does considerably reduce & almost eliminate the pinging/rattle for normal street driving. So overall I will continue to use the higher octane fuel because personally I notice enough difference overall in my JL to think it's worth the few extra dollars each time I fuel up especially since the thing set us back 70k.But of course this is my own personal experience & observation with our JL & for others their experiences could be different because one thing I've learned about cars over 30+ years of driving them is that like people they can be temperamental & one doesn't always behave like another. 2 cars off the same production line built minutes apart can be completely different, 1 an awesome build with little to no issues & the other a lemon with every issue you can imagine. Enough people across enough forums & threads are describing the exact same issue which means it exists & is common enough to spawn countless threads on the problem so it is obviously a common enough problem to warrant Jeeps attention to finding the problem & rectifying it. The higher octane fuel clearly does not rectify the problem completely by any means but it's a short term alleviation of the issue that people can easily do themselves which won't affect or void warranties or do any damage until such time as Jeep addresses it with a fix. If you are one of the many who have no issues with your Jeep pinging then consider yourself lucky but bare in mind that many of us do have this issue & until Jeep comes to the party these forums & discussions are all we have to communally discuss these issues & try to find solutions & I for one find this forum to be an awesome tool for finding info & fixes for bugs & faults especially ones that Jeep themselves are denying the existence of or have not yet found a fix for. Our JL is auto 8spd & has done just over 32,000klms.
 

DanW

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In Australia our octane level is calculated differently which gives us 91, 95 or 98 octane fuel ratings. Our jeeps are recommended to run on our 91 octane which I believe is equivalent to the US 87. Our JL Overland Unlimited was bought new in 2019 & I definitely noticed the rattling/ping but only at low speeds/revs & only after the engine was well warmed up. It seems to be especially prominent & worse when 4 wheeling at low speeds & climbing. I went looking for threads on this issue as it seemed to be getting worse & tried the highest octane fuel to remedy the problem. My observations after a couple of months using our 98 octane fuel from BP are - pinging/rattle is very much reduced with normal street driving & barely noticeable but when offroading in 4wd it is still very prominent & at it's loudest & worse. Fuel economy appears to be a little improved but marginal & not enough to make a big song & dance about (maybe half a litre per hundred kilometers better) but it does seem to run a little smoother & have slightly more get up & go & a bit more responsive to pedal input but again nothing to write home about by itself but all combined it does add up to an improvement overall with power, economy & smoother running even if it is only marginal, but using the high octane does considerably reduce & almost eliminate the pinging/rattle for normal street driving. So overall I will continue to use the higher octane fuel because personally I notice enough difference overall in my JL to think it's worth the few extra dollars each time I fuel up especially since the thing set us back 70k.But of course this is my own personal experience & observation with our JL & for others their experiences could be different because one thing I've learned about cars over 30+ years of driving them is that like people they can be temperamental & one doesn't always behave like another. 2 cars off the same production line built minutes apart can be completely different, 1 an awesome build with little to no issues & the other a lemon with every issue you can imagine. Enough people across enough forums & threads are describing the exact same issue which means it exists & is common enough to spawn countless threads on the problem so it is obviously a common enough problem to warrant Jeeps attention to finding the problem & rectifying it. The higher octane fuel clearly does not rectify the problem completely by any means but it's a short term alleviation of the issue that people can easily do themselves which won't affect or void warranties or do any damage until such time as Jeep addresses it with a fix. If you are one of the many who have no issues with your Jeep pinging then consider yourself lucky but bare in mind that many of us do have this issue & until Jeep comes to the party these forums & discussions are all we have to communally discuss these issues & try to find solutions & I for one find this forum to be an awesome tool for finding info & fixes for bugs & faults especially ones that Jeep themselves are denying the existence of or have not yet found a fix for. Our JL is auto 8spd & has done just over 32,000klms.
I'm not sure much can be done via the PCM, so this is just me and the stabs I would take at it. I'd probably start with new spark plugs and go from there. Maybe one or more are not gapped properly.

My JK used to ping and knock when carbon would build up. Two things improved it. First, I'd run some Shell V-Power through it (1 tank usually cleared it up) and a few Italaian tune-ups (hard full throttle runs to red line.) Twice, that did not work, so I changed the spark plugs and gapped them properly and precisely and in those cases the pinging stopped.

Since then, Shell reformulated their 87 gasoline additive package and I've not dealt with it since. But I also now change spark plugs every 40k miles instead of the recommended 100k.

So that's my rationale. It might not work, but as annoying as the pinging can be, I'd give it a shot. I do know it is a little harder to change the plugs in the 3.6 than in my old 3.8 due to removal of the intake manifold. But at the end of the day, this engine should not ping. Most of them don't. So something is amiss, even if only slightly.

That's my humble suggestion and it is really nothing more than an educated guess. I hope you get it cured so that you can fully enjoy that machine the way it was meant to be.
 

DanW

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113 degrees here yesterday. 87 in the tank, no knocking no pings. '21 Willys
Wow, I can't believe the heat wave you are experiencing up there!
 

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113 degrees here yesterday. 87 in the tank, no knocking no pings. '21 Willys
The weather is nuts up there. My sister just got back to Texas from Seattle and couldnt believe how our weather patterns were reversed right now.
 

DanW

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The weather is nuts up there. My sister just got back to Texas from Seattle and couldnt believe how our weather patterns were reversed right now.
Well, our thoughts are with you. Hopefully it will break soon. We've had a pretty mild season, so far. But the summer is young!
 
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Petey

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In Australia our octane level is calculated differently which gives us 91, 95 or 98 octane fuel ratings. Our jeeps are recommended to run on our 91 octane which I believe is equivalent to the US 87. Our JL Overland Unlimited was bought new in 2019 & I definitely noticed the rattling/ping but only at low speeds/revs & only after the engine was well warmed up. It seems to be especially prominent & worse when 4 wheeling at low speeds & climbing. I went looking for threads on this issue as it seemed to be getting worse & tried the highest octane fuel to remedy the problem. My observations after a couple of months using our 98 octane fuel from BP are - pinging/rattle is very much reduced with normal street driving & barely noticeable but when offroading in 4wd it is still very prominent & at it's loudest & worse. Fuel economy appears to be a little improved but marginal & not enough to make a big song & dance about (maybe half a litre per hundred kilometers better) but it does seem to run a little smoother & have slightly more get up & go & a bit more responsive to pedal input but again nothing to write home about by itself but all combined it does add up to an improvement overall with power, economy & smoother running even if it is only marginal, but using the high octane does considerably reduce & almost eliminate the pinging/rattle for normal street driving. So overall I will continue to use the higher octane fuel because personally I notice enough difference overall in my JL to think it's worth the few extra dollars each time I fuel up especially since the thing set us back 70k.But of course this is my own personal experience & observation with our JL & for others their experiences could be different because one thing I've learned about cars over 30+ years of driving them is that like people they can be temperamental & one doesn't always behave like another. 2 cars off the same production line built minutes apart can be completely different, 1 an awesome build with little to no issues & the other a lemon with every issue you can imagine. Enough people across enough forums & threads are describing the exact same issue which means it exists & is common enough to spawn countless threads on the problem so it is obviously a common enough problem to warrant Jeeps attention to finding the problem & rectifying it. The higher octane fuel clearly does not rectify the problem completely by any means but it's a short term alleviation of the issue that people can easily do themselves which won't affect or void warranties or do any damage until such time as Jeep addresses it with a fix. If you are one of the many who have no issues with your Jeep pinging then consider yourself lucky but bare in mind that many of us do have this issue & until Jeep comes to the party these forums & discussions are all we have to communally discuss these issues & try to find solutions & I for one find this forum to be an awesome tool for finding info & fixes for bugs & faults especially ones that Jeep themselves are denying the existence of or have not yet found a fix for. Our JL is auto 8spd & has done just over 32,000klms.
Backing timing of a few degrees would be great if it was an alternative. Or basically a brand new spark advance curve. Ah distributors....miss the old days. I use the lucas fuel treatment and it definitely knocks a bit of the edges on gas. ..and with high octane u should hear a bigger difference.
 

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I have the answer to everyones question... and here it goes. If it runs good on 87, and you are happy then run 87. If you feel the need to run 91, run 91. Its a little more expensive but I care about what I feed my baby. Its that simple. This isn't a debate its a matter of choice and economics. 99% of the people reading this may not notice any difference at all running 87 or 91, unless influenced by reading this thread. Its not a problem til you make it one.
 

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I have the answer to everyones question... and here it goes. If it runs good on 87, and you are happy then run 87. If you feel the need to run 91, run 91. Its a little more expensive but I care about what I feed my baby. Its that simple. This isn't a debate its a matter of choice and economics. 99% of the people reading this may not notice any difference at all running 87 or 91, unless influenced by reading this thread. Its not a problem til you make it one.
Agreed. The problem isn't what you run in your Jeep, the problem is harassing others over what they run in THEIR Jeep. Just do you, and let them do them. You may think it's nuts to waste money on premium, but then you may not realize that they are super lucky and only pay an extra $0.20/gal to do so. I think i'd just run premium in all my cars if life were that simple for me. Unfortunately I pay $0.70-$1.00 extra, which makes ROI very difficult to achieve.
 

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