Rattling upon acceleration

[Maverick909]

i have the same noise. started about 3k miles. i am at 6k now and have tried to change my driving habits on my manual transmission but still get that noise.. I took it in for the steering damper recall and asked them to check out the noise. i also told them that it had to be at full operating temp on the transmission when they drove it but they did not do that. so they asked me to come drive the tech and replicate the noise. well they wouldn't allow me the time to get the jeep trans to full temp. i was told that there is nothing there and if it get worse to come back. i figured at least its in writing that i have an issue and when i get stuck on a trip they are going to have to pay to tow it to a dealer to fix it.. anywhom i will try the 91 oct fuel and see if it is better. ill report soon

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[AU_JLU]

I too have been battling with the pinging pre ignition and running top tier gas exclusively, 3.6 8 speed auto JLU. It seems it does it most when the transmission picks a high gear and is slightly labouring. Seeing that Jeep will not come to the party with a new tune and the fact the JL ECU is locked down I was looking for other solutions. I started to wonder about the Tazer, in particular changing the gear ration setting. Does anyone have experience with the tazer? I am wondering if changing the gear ratio setting will cause the transmission shift up into high gears a little later. This should keep the engine out of the low rpm labouring ranging and should cut down on most of the pre ignition ping?
Thoughts?

 

[CZ 75]

I too have been battling with the pinging pre ignition and running top tier gas exclusively, 3.6 8 speed auto JLU. It seems it does it most when the transmission picks a high gear and is slightly labouring. Seeing that Jeep will not come to the party with a new tune and the fact the JL ECU is locked down I was looking for other solutions. I started to wonder about the Tazer, in particular changing the gear ration setting. Does anyone have experience with the tazer? I am wondering if changing the gear ratio setting will cause the transmission shift up into high gears a little later. This should keep the engine out of the low rpm labouring ranging and should cut down on most of the pre ignition ping?
Thoughts?

It would be interesting to test. I thought going to 37s would force the engine to work harder and hold higher rpms but basically in gears 1 through 5 I don't notice any difference. On the highway it'll hold 6 and 7th more often than 8th.

 

[HiJinx69]

I really couldn't hear much in some of the audio clips on this thread, but here is what mine does. It's pretty clear. This was on a trail lined with trees that bounced the sound back. It only happened at low rpms, uphill and low speeds. I hear it in normal street driving, but doesn't happen all the time. Been under the Jeep to see if there was anything hitting, but couldn't see anything that touches the engine or exhaust. Heat shield is not metal, foil lined on soft material from what I can tell.

 

[Snowshoes]

I really couldn't hear much in some of the audio clips on this thread, but here is what mine does. It's pretty clear. This was on a trail lined with trees that bounced the sound back. It only happened at low rpms, uphill and low speeds. I hear it in normal street driving, but doesn't happen all the time. Been under the Jeep to see if there was anything hitting, but couldn't see anything that touches the engine or exhaust. Heat shield is not metal, foil lined on soft material from what I can tell.

Nice video. I hear the exact same noise going uphill, low rpms and when the engine reached normal operating temperature.

 

[unsavory]

I really couldn't hear much in some of the audio clips on this thread, but here is what mine does. It's pretty clear. This was on a trail lined with trees that bounced the sound back. It only happened at low rpms, uphill and low speeds. I hear it in normal street driving, but doesn't happen all the time. Been under the Jeep to see if there was anything hitting, but couldn't see anything that touches the engine or exhaust. Heat shield is not metal, foil lined on soft material from what I can tell.

That's definitely pretty bad engine knock, and it is horrible for the longevity of your engine. Mine does this too if I accidentally lug it while climbing hills (manual transmission). As others have also mentioned, gotta keep those RPMs up above 2200 pretty much all the time!

 

[JeepCares]

I really couldn't hear much in some of the audio clips on this thread, but here is what mine does. It's pretty clear. This was on a trail lined with trees that bounced the sound back. It only happened at low rpms, uphill and low speeds. I hear it in normal street driving, but doesn't happen all the time. Been under the Jeep to see if there was anything hitting, but couldn't see anything that touches the engine or exhaust. Heat shield is not metal, foil lined on soft material from what I can tell.

Hi Dan,
Are you considering having your dealer look into this further. Feel free to keep us updated via PM! We would be happy to connect you with a Case Specialist if need be.
Alex
Jeep Cares

 

[AU_JLU]

Hi Dan,
Are you considering having your dealer look into this further. Feel free to keep us updated via PM! We would be happy to connect you with a Case Specialist if need be.
Alex
Jeep Cares

@Jeep Cares , My dealer said the pinging/knocking is normal even though I use the highest grade fuel. They diagnosed this without measuring the knock readout with a scan tool. Is there a way you can raise case with Jeep. We need a TSB update with a corrected engine tune.

 

[AU_JLU]

On a GC forum a guy was complaining of the exact same conditions on his 2017 grand chorokee 3.6.
The dealer carried out the following TSB and it fixed the issue. This TSB mentions 'improved knock sensor performance'.
Doesn't the current JL run an almost identical 3.6 to the 2017 GC?
Looks like enough of us need to complain so Jeep issues an update fix.
http://www.wk2jeeps.com/tsb/tsb_wk2_1804916b.pdf

 

[JeepCares]

@Jeep Cares , My dealer said the pinging/knocking is normal even though I use the highest grade fuel. They diagnosed this without measuring the knock readout with a scan tool. Is there a way you can raise case with Jeep. We need a TSB update with a corrected engine tune.

Hi Lloyd,
If you would like to send us a private message with your VIN and current mileage, I would be happy to document your concern in a case.
Alex
Jeep Cares

 

[Tiger97]

I too have the same issue and my dealer had my car for 9 days trying to diagnose and fix. The tech rode with me so he could hear the noise. The tech confirmed the sound was pre-spark ignition after working with Jeep Engineering.

The tech first confirmed there were no codes. He then took a fuel sample and confirmed it was good with very low ethanol content (was BP 93 octane). The tech checked the fuel pressure and it was good.

The tech reset the crankshaft and cam shaft position sensors and reset the timing “learning”. These had no effect. They replaced the knock sensors and wiring harness and claimed the wiring harness wasn’t routed properly. They indicated it was damaged, but would not tell me if one of the conductors was grounded or open, or if the connectors were pinned improperly. They returned the vehicle to me claiming success.

It did not fix the issue. I heard it again on the way home. I drove it for a few days to see if the timing would adjust (assuming the new knock sensors and wiring did fix a defect), but it is the same as before. I have scheduled to take it in for 2nd attempt next week. I have contacted Jeep customer care center and opened a case. The service dept at my dealer doesn’t know what else to do. All of the things they did were at the guidance of Jeep Engineering according to the Tech. Think we are way beyond the service manual procedure at this point.

Very frustrating and not impressed with my first Jeep. Will be my last. Friends, family, and co-workers have heard this story. You can guess their reaction regarding Jeep products.

 

[Tiger97]

I too have the same issue and my dealer had my car for 9 days trying to diagnose and fix. The tech rode with me so he could hear the noise. The tech confirmed the sound was pre-spark ignition after working with Jeep Engineering.

The tech first confirmed there were no codes. He then took a fuel sample and confirmed it was good with very low ethanol content (was BP 93 octane). The tech checked the fuel pressure and it was good.

The tech reset the crankshaft and cam shaft position sensors and reset the timing “learning”. These had no effect. They replaced the knock sensors and wiring harness and claimed the wiring harness wasn’t routed properly. They indicated it was damaged, but would not tell me if one of the conductors was grounded or open, or if the connectors were pinned improperly. They returned the vehicle to me claiming success.

It did not fix the issue. I heard it again on the way home. I drove it for a few days to see if the timing would adjust (assuming the new knock sensors and wiring did fix a defect), but it is the same as before. I have scheduled to take it in for 2nd attempt next week. I have contacted Jeep customer care center and opened a case. The service dept at my dealer doesn’t know what else to do. All of the things they did were at the guidance of Jeep Engineering according to the Tech. Think we are way beyond the service manual procedure at this point.

Very frustrating and not impressed with my first Jeep. Will be my last. Friends, family, and co-workers have heard this story. You can guess their reaction regarding Jeep products.

It is a 2019 JLU 3.6L V6. Forgot to provide those details.

 

[thiskneeguy]

This is incredible. My JLUS makes this same exact knocking noise under the same conditions. it also has the clicking suspension. Took it to the dealer and they kept it for a week and said they couldn’t reproduce and that the vehicle was operating normally. Not too worried about getting it fixed since I’m leasing it. I’m assuming there will be some sort of TSB on both of these in the future. These problems also aren’t surprising, either. After all, we’re all driving around in Chryslers masquerading as Jeeps.

 

[HiJinx69]

I really couldn't hear much in some of the audio clips on this thread, but here is what mine does. It's pretty clear. This was on a trail lined with trees that bounced the sound back. It only happened at low rpms, uphill and low speeds. I hear it in normal street driving, but doesn't happen all the time. Been under the Jeep to see if there was anything hitting, but couldn't see anything that touches the engine or exhaust. Heat shield is not metal, foil lined on soft material from what I can tell.

Update. I just went through a full tank of high octane gas. Surprisingly, there was no knock. I don't know if weather was a factor. Daytime temps were in the 70's. Also, I averaged 18 mpg, I was getting 16 prior. I also noticed the engine ran smoother, before it seemed to work harder and rougher. Hence the increased MPG.

This is kinda sad, that I have to pay more in gas. There's got to be a better tune in the fuel management for this issue. Jeep needs to get on it!

 

[thiskneeguy]

Update. I just went through a full tank of high octane gas. Surprisingly, there was no knock. I don't know if weather was a factor. Daytime temps were in the 70's. Also, I averaged 18 mpg, I was getting 16 prior. I also noticed the engine ran smoother, before it seemed to work harder and rougher. Hence the increased MPG.

This is kinda sad, that I have to pay more in gas. There's got to be a better tune in the fuel management for this issue. Jeep needs to get on it!

I am also about halfway through a tank of 93 octane and the knocking noise is almost non-existent anymore whereas with 87 it was alarmingly loud. The engine also feels much smoother and even feels a bit peppier when accelerating. Guess I'll be spending more on gas...

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