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Wrangler Rubicon JLU 3.6 engine pre-detonation

Jeepcity

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They will start Knocking just out of warranty . Hyundai is fixing their screw up . I am betting FCA will not .
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MurphysLaw

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As an update, jeep service dept took a look and said yes it's engine pinging and It's normal on wranglers... just part of the timing and tune on the engines with 87 octane. They suggested running higher octane during hotter weather. ( It's a jeep thing basically lol )
 

schumbox

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Here is the sound of pre-detonation on a 2019 Jeep JLUR with the 3.6L with a 6-speed manual. Please turn up the volume when listening.



This instance was created in 2nd gear with a very slight load. Can be produced in more areas of RPM, but this was easiest to record.
Issue was created and recorded on 2019 Rubicon with 3.6 and manual.
Issue was reproduced on 2019 Sahara with 33 miles and 3.6 w/manual.
Issue was also reproduced on 2018 Sport with automatic. With automatic transmission, condition is much more difficult to reproduce due to characteristics of torque management.

From OM:
“While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see your dealer immediately. Use of gasoline with an octane number lower than 87 can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty."


I document each fill up and location. Normally run 87 octane. Have run multiple tanks of 91 octane with same results.

Currently waiting for an FCA regional engineer to show up at my local dealership.

Assume Gladiator is no different. Last (no longer working for) FCA engineer said issue is ‘Normal’…..‘Typical’ of all JL’s, but not ‘Normal’!

#FCAEngineEngineering – Your dealers need help!
 

intentsrig

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Here is the sound of pre-detonation on a 2019 Jeep JLUR with the 3.6L with a 6-speed manual. Please turn up the volume when listening.



This instance was created in 2nd gear with a very slight load. Can be produced in more areas of RPM, but this was easiest to record.
Issue was created and recorded on 2019 Rubicon with 3.6 and manual.
Issue was reproduced on 2019 Sahara with 33 miles and 3.6 w/manual.
Issue was also reproduced on 2018 Sport with automatic. With automatic transmission, condition is much more difficult to reproduce due to characteristics of torque management.

From OM:
“While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see your dealer immediately. Use of gasoline with an octane number lower than 87 can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty."


I document each fill up and location. Normally run 87 octane. Have run multiple tanks of 91 octane with same results.

Currently waiting for an FCA regional engineer to show up at my local dealership.

Assume Gladiator is no different. Last (no longer working for) FCA engineer said issue is ‘Normal’…..‘Typical’ of all JL’s, but not ‘Normal’!

#FCAEngineEngineering – Your dealers need help!
I agree with it not being normal. My buddy's JK 3.6 never pings. I know the JL is a different version of the 3.6 as well.

My 3.8 pinged in a very similar way but even a little worse. It never blew up but only had about 70k on it when I sold it.
 

Jimmy_jak

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My 2019 Sport S 3.6 AT has this. Dealera said run different gas for a few tanks
 

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Dunno about the knocking noises but mine vibrates in a really annoying manner.
 

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Here is the sound of pre-detonation on a 2019 Jeep JLUR with the 3.6L with a 6-speed manual. Please turn up the volume when listening.



This instance was created in 2nd gear with a very slight load. Can be produced in more areas of RPM, but this was easiest to record.
Issue was created and recorded on 2019 Rubicon with 3.6 and manual.
Issue was reproduced on 2019 Sahara with 33 miles and 3.6 w/manual.
Issue was also reproduced on 2018 Sport with automatic. With automatic transmission, condition is much more difficult to reproduce due to characteristics of torque management.

From OM:
“While operating on gasoline with an octane number of 87, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see your dealer immediately. Use of gasoline with an octane number lower than 87 can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty."


I document each fill up and location. Normally run 87 octane. Have run multiple tanks of 91 octane with same results.

Currently waiting for an FCA regional engineer to show up at my local dealership.

Assume Gladiator is no different. Last (no longer working for) FCA engineer said issue is ‘Normal’…..‘Typical’ of all JL’s, but not ‘Normal’!

#FCAEngineEngineering – Your dealers need help!
Did the engineer show up regarding this? What was the result? How are things currently? I am having some knocking and want to know what's up. Dealer told me to try a different gast station.
 

schumbox

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Did the engineer show up regarding this? What was the result? How are things currently? I am having some knocking and want to know what's up. Dealer told me to try a different gast station.
Not enough customers have complained to dealerships, which is what drives change. Engineering denies issue due by stating 'as designed'.
 

jeepdabest

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I had a Miata that suffered from pre detonation all the time....until I taught it to think about baseball scores.
 

cmc.703

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I may get hate for this, but I am honestly just looking out for ya'll.

The compression ratio on the 3.6L is 11.3:1
Anything over 10:1 is considered high compression.

FCA wanted to keep the annual fuel usage cost down on the monroney sticker, so they opted out of premium fuel requirements.

The 3.6L definitely detonates on 87, even if just a little. This is damaging to an ICE!

The engine has knock sensors on the block, they detect detonation and the PCM will pull timing to compensate for this. This affects performance!

I truly believe that FCA wants everyone to use cheap gas, so when the warranties are expired they can sell you parts.

Think for yourself ya'll !! I'm a lead foot so I choose to use premium fuels.
Peace and love!!


p.s., BG 44K is amazing stuff.
 

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intentsrig

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I may get hate for this, but I am honestly just looking out for ya'll.

The compression ratio on the 3.6L is 11.3:1
Anything over 10:1 is considered high compression.

FCA wanted to keep the annual fuel usage cost down on the monroney sticker, so they opted out of premium fuel requirements.

The 3.6L definitely detonates on 87, even if just a little. This is damaging to an ICE!

The engine has knock sensors on the block, they detect detonation and the PCM will pull timing to compensate for this. This affects performance!

I truly believe that FCA wants everyone to use cheap gas, so when the warranties are expired they can sell you parts.

Think for yourself ya'll !! I'm a lead foot so I choose to use premium fuels.
Peace and love!!


p.s., BG 44K is amazing stuff.
If I don’t use premium I get detonation all the time. Always use premium. At least with the manual.
 

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So trying to understand the premium vs non premium...should I try premium to test the knocking? If so...how high a grade should I go?
 

cmc.703

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So trying to understand the premium vs non premium...should I try premium to test the knocking? If so...how high a grade should I go?
Hey man, I would recommend using at least 89 octane. If you can afford it, premium fuels will keep your engine running better longer. Shell and Sunoco have proprietary blends of premium octanes which help reduce carbon deposit on the top end of the motor. I know this because I've seen the inside of a couple of my motors :D
 

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Hey man, I would recommend using at least 89 octane. If you can afford it, premium fuels will keep your engine running better longer. Shell and Sunoco have proprietary blends of premium octanes which help reduce carbon deposit on the top end of the motor. I know this because I've seen the inside of a couple of my motors :D
Yeah I'm good for the $ lol. Just trying to understand. I appreciate it.
 

chacomaya

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I'll add my .02 here...I had this same thing and switching to 89 octane completely fixed it. Gasoline brand doesn't seem to matter, at least in my case.

Also, not to be pedantic but I've seen a few folks use the term "pre detonation". This isn't a thing. There is pre-ignition, and there is detonation, and they are completely different from one another.
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