Predetonation/spark knock

[iflyimpilot]

I had about 1/4 tank of 87 last week and topped off with 93. It seemed to make the knocking go away. Was down to 1/4 tank again a week later (today) and topped off with 93 once more. On my way home from work it seemed to have come back. Today was a really hot/humid day and I had the A/C on the entire time. I wonder if high ambient temperatures seem to make it more apparent.

Another thing I wanted to note was in the manual on pages 504-505 under Fuel Requirements for the 3.6L Engine, it says:

"While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern."

Not sure what exactly is meant by this but I found it interesting. It says the same thing for the 2.0L Engine but for the recommended 91 octane.

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[Owenage]

I wonder what Jeep considers "light knocking"?

 

[shotcoach]

3.6 Auto. I've had mine since February and have over 12,000 miles on it. I've been experiencing the same knocking under light acceleration for the last 2-3 weeks. I've been hesitant to take it to the dealer knowing that it's intermittent and I'll likely hear that they were unable to reproduce. Sounds like I should take it in nonetheless just to document the issue.

 

[AZ Hella]

The best way to tell if it’s fuel related is to add 1 gallon of e85 to a full tank. ( if available). It will bump the octane up. It’s perfectly safe. It will put you at about e15 which is acceptable.

 

[LITTLE MULE]

Mine is having the same problem I only have 6,000 miles on mine 3.6 automatic just noticed it a couple days ago

 

[Crusifix]

The best way to tell if it’s fuel related is to add 1 gallon of e85 to a full tank. ( if available). It will bump the octane up. It’s perfectly safe. It will put you at about e15 which is acceptable.

Actually that will not bump the octane up very much. E15 is equivalent to 88 Octane.

 

[JeepCares]

Mine is having the same problem I only have 6,000 miles on mine 3.6 automatic just noticed it a couple days ago

Hi LITTLE MULE,

We're sorry to hear you're experiencing this. If you end up going into the dealer for an inspection, let us know. Our team is available via direct message and would be happy to help with that process.

Jasmine
Jeep Social Care Specialist

 

[Snowshoes]

The speed limit from where I live to where I work is 20 mph with about 4-5 stop signs, and this seems to be where it happens most, always at lower RPMs. There will be a rattle in the motor for about 3-5 seconds on acceleration, and then it goes away. I can recreate the issue by pressing the gas, releasing the gas, and pressing it again. Now, I know that I'm recreating it because I'm confusing the computers VVT, but it's the only way I can reproduce the sound I'm hearing while the tech is with me.

Do you still have this issue? I have same rattling noise going uphill. It only happens when the engine is at operating temperature. I can reproduce the rattle like you did releasing and pressing the gas. I tried 91 octane which only helped a bit. I think this is a tune issue like other forum members mentioned in other thread.

 

[RustyJeep]

I have a manual 3.6 JLR and it has been making this so called “spark knock” since day 1. Tried running on every type of gas going from 87 to 94, it may go away at times, even with the highest octane, but i think it’s all in my head. The noise is still there no matter what. I used to have a 2005 JK with the same problem also from day 1, thats the reason why i sold it because i thought the engine will seize sooner or later. I also noticed this issue on Toyotas, especially taxi cars, while in traffic, when they accelerate sometimes it sounds really bad. There maybe is an answer on a Toyota forum. Clearly Chrysler and their engineering team has no idea what they have built, funny how they have been quiet on the forums all these years. From what i understand our engine’s computer has no control of the fuel in the cylinder, it ignites whenever it feels like, messes up the timing and momentum and your entire driving experience. Another dumb thing i noticed is, when i throw my gears in neutral from say like 3000 rpm, it goes down to where it’s idle, but then gases the engine automatically, creating our favorite knock knock wtf sound. Whatever happened to good old days where engines used to work just fine without any added dumbness to them, like self throttling on a god damn manual. Really pissed with Chrysler, probably hired a bunch of noobs.

 

[DogsOnTheRun]

I have a 2019 3.6 auto, 7k miles. Just started noticing the spark knock at light throttle only, and only very occasionally. When it happens, I back off, and it stops. Restart the engine for the trip home and no knocking at all, like magic.

It has always made a bit of a diesel noise on idle. I thought this was likely engineered-in to make it sound "like a Jeep", which it does to me at idle.

I am sure the dealer will not be able to duplicate. Shame the engine doesn't just log knocking events as they occur.

 

[Vihoula]

My 2019 Sahara auto does it too, it’s embarrassing, sounds gutless. 7,000 kms

 

[bwright1818]

I wonder what Jeep considers "light knocking"?

This is kind of like "a little bit pregnant." Another carefully-worded statement by the FCA masters of avoidance and deception, like the infamous, "Vehicle operating as designed." I honestly feel that I have never heard or felt a worse sounding, worse-running engine. But hey, that's why they get the big money for these things. Does this knocking happen between 1500 and 1700 RPM by chance? I know that there are some serious tune issues with mine, in that range.

 

[RustyJeep]

It can be anywhere from 1500 to 2500 but the sweetest spot for me is at 2000, if I lightly press the pedal just to maintain speed, that's where the engine gets all confused and starts knocking, It happens in every gear, under slight load at or near 2000. To me it feels like either there are pressure issues plus mismatch in fuel to air ratios, which is only tuning hopefully because for example, at around 28mph in 3rd gear i'm at around 2000rpm, so if i throttle up heavy or light, it will knock regardless for a split second to a second, jeep also feels like 230hp not 275hp during those moments, the fuel efficiency is 2 gallons under the proposed fuel efficiency. I don't get it, the Jeep engineering team never logs on to these forums to see what people say about their Jeep, for feedback? The confidence there has to be through the roof, "if you experience light knocking it's ok YOU'LL LIVE!!!

 

[Capricorn]

Thank God I have a 2.0L.

 

[PizzaFreak]

Hmmmmm! I still only use 93, I have 6000 miles and my Jeep is a beast. MPG is almost 25/gallon and power/acceleration is outstanding! There is absolutely no knocking any any rpm’s ever. It only stands to reason, you get what you pay for! I stand by the 93, nothing can convince me otherwise!

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