2021 Jeep Wrangler 2.0, strange noise at cold start.

[starrman73]

When this engine started it seems to go through a “ticking” cycle for about 90 seconds before you finally hear the Cold Air Intake take a deep breath (around the 1:33 mark) and finally go to normal. It does this on every cold start now. I've had several Jeeps (JL's and JK's). I realize they are noisy. None them did (or do) this.

Video:

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[Jim1964]

I believe that’s pretty typical with GDI engines on cold start. Sounds a bit like a diesel and mine romps a bit as yours does.

 

[starrman73]

I believe that’s pretty typical with GDI engines on cold start. Sounds a bit like a diesel and mine romps a bit as yours does.

If my other two JL's were doing this I would agree. However, this is the only one that does it. We've started them back to back from a cold start and this one is definitely the only one doing it.

 

[Remorseless]

After it calms down, does it ever come back under load/acceleration?

 

[starrman73]

After it calms down, does it ever come back under load/acceleration?

Nope. Once it goes through that 90 second cycle you don't hear it again until it is cold. You can shut it off and turn it back on and she sounds fine. Only happens from a cold start.

 

[Remorseless]

Nope. Once it goes through that 90 second cycle you don't hear it again until it is cold. You can shut it off and turn it back on and she sounds fine. Only happens from a cold start.

Weird, timing chain tensioners seem to be something a few other folks have had problem with, but they got rattles at start and at a few points in the rev range.

Hmm, with the engine cover off, can you feel vibrations from the noise in any particular spot, or does it sound like it's coming from a specific part of the engine (front, back, one of the sides)?

 

[starrman73]

Weird, timing chain tensioners seem to be something a few other folks have had problem with, but they got rattles at start and at a few points in the rev range.

Hmm, with the engine cover off, can you feel vibrations from the noise in any particular spot, or does it sound like it's coming from a specific part of the engine (front, back, one of the sides)?

Funny you should ask. I actually put my hand on the cover to see if I could feel it. No real "oddness" felt but the sound seemed like it was coming from right under that cover. Now, is that just vibration noise coming from somewhere else? Don't know.

Additionally, I did the following sanity checks:
- Checked codes, no codes coming up.
- Changed oil and filter (early than I needed to).
- Check for anything "loose" (like that would make it consistency happen, but hey, why not?)
- Ran the gas out of it, filled up with Mucho premium gas.
- Started other two jeeps and compared oil pressure at start up. No difference.

 

[Remorseless]

Funny you should ask. I actually put my hand on the cover to see if I could feel it. No real "oddness" felt but the sound seemed like it was coming from right under that cover. Now, is that just vibration noise coming from somewhere else? Don't know.

Additionally, I did the following sanity checks:
- Checked codes, no codes coming up.
- Changed oil and filter (early than I needed to).
- Check for anything "loose" (like that would make it consistency happen, but hey, why not?)
- Ran the gas out of it, filled up with Mucho premium gas.
- Started other two jeeps and compared oil pressure at start up. No difference.

There's a fair bit of padding in that engine vanity cover, might give you a more precise idea what's up with it off and listening/feeling.

 

[starrman73]

There's a fair bit of padding in that engine vanity cover, might give you a more precise idea what's up with it off and listening/feeling.

Roger that. Will pull it and see if I can get a more precise ear on it.

 

[jjvincent]

What does it wound like with the OEM intake on it?

 

[starrman73]

Roger that. Will pull it and see if I can get a more precise ear on it.

Pulled. Still sounds like it coming from the same place.

 

[starrman73]

What does it wound like with the OEM intake on it?

Had the same issue prior to installing the cold air intake.

 

[7c102c600853ce38121]

Mine has the same issue. Dealer said it sounds like cam chain tensioners and they will be changing those in mine.

 

[longfiredragon]

I didn't hear any ticking noise outside of what the 2.0L sounds like normally, which I attribute to the direct injection mostly until everything gets fully up to operating temp.

What I did hear that sounded abnormal is a sound that comes in, and then goes out. To me it sounds very much like something vibrating in and out. I know you checked a bunch of stuff already, but I would keep checking different items and see if you can pin point something. I know cam chain tensioner has been mentioned, but, you would think that if the cam chain tensioner does it cold it would continue to do it when warmed up, but maybe not, maybe it is sticking somehow. I would have to refresh myself on how the system works.

That is very weird that at 1:33 into start up the engine goes into a diff. mode and it just stops.

 

[starrman73]

The dealership wanted to keep the vehicle for 4 days (because, staff shortages. Don't get me started) and that was a no-go. So, I reached out to S&B and they responded very quickly.

"After reviewing the video of the noise, it seems to be normal for the that type of engine. For direct injection engines during cold start, will make a lot of chatter. The noise will be cause by the high pressure fuel injectors. I have a direct injected turbo charged vehicle as well, it sounds like a tractor in the mornings. The noise would have been amplified by the size of the intake tube and the decrease in restriction. There is nothing to worry about with the noise."

...I responded with, "my other JL doesn't sound this way". His response:

"The other JL's with the 2.0L TC will have the same noise. It will be less noticeable since the stock intake tube will have resonators and baffling to dampen engine noises. if you change the intake to one of the other ones I am sure that the noise will be noticeable. The reason I asked if it was only at cold start or during every start, is because engine components expand with heat. On cold starts, the tolerances between components are large and create a chattering noise. Once allowed to heat up the tolerances become smaller and the noises decrease."


Kudo's to S&B for providing quick, detailed, responses. Still concerned a little but will let it play out and see how it goes.

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