[billyroku]

My Cadenza has had this issue for a while (probably for less than five years). Whenever I cold start my car, in reality it’s 80 degrees cold, the timing chain clatters for at the most 5 seconds and the exhaust burbles for probably 30 seconds, then roughly smoothens out. On warm starts the timing chain clatters but no burbling. I believe my grandfather (who originally owned this before me), had the timing chain tensioner recall done, but I do not have the service records on me. Mechanic who we have been with for several years gave us three additives for the burbling, two fuel one oil, that didn’t work. I’m not sure if I have to get the tensioners done again, but if that’s the case, could it be causing the burbling. And is there a warranty for the recall that is transferable, since I am not the original owner?

 

[onlyjeeps]

I had the final revision of the TSB (#4 maybe?) done to my tensioners with no help what so ever. It made no difference and they still continue to clatter every cold start. I have 100k on it now and no signs of engine issues so I guess the clattering is fine. Different times over the years I've tried an additive when I change the oil and that seems to lessen the clattering but I doubt anything mechanical is changing such as less wear.

I don't understand what you mean by burbling so I don't know how to address that. All cars cold start up with a richer/rougher sounding exhaust note when they first start because of the rich fuel mixture the computer sets to start the engine. I assume you mean something else. I've not heard anything out of the ordinary coming from my exhaust.

 

[billyroku]

I don't understand what you mean by burbling so I don't know how to address that. All cars cold start up with a richer/rougher sounding exhaust note when they first start because of the rich fuel mixture the computer sets to start the engine. I assume you mean something else. I've not heard anything out of the ordinary coming from my exhaust.

I am having trouble posting the video of it, so I’ll try describing it to the best of my ability. Whenever it cold starts, the exhaust makes the sound similar to popcorn popping. Almost like a mini gun is firing. It only does it for less than 30 seconds, and then the rpm’s go up and it smoothens out, and when it makes that “burbling” it’s pretty quiet but noticeable. Once again, I can’t get the video posted here, but hearing it describes it much better than I do.

 

[onlyjeeps]

What stands out to me in your description is the part where you say the rpm's go up after the odd noises stop. That is not normal in my experience. On a cold start, once the car fires, it immediately goes up to a high idle of approximately 1200-1300 rpm's. Then over the next 30-60 secs it will slowly come down as it slightly warms up, down to the normal idle of about 850 rpm's.
So if your car is making odd sounds and not going up to it's high idle I would say something is wrong like it's missing and misfiring. Those things should cause the engine light to illuminate though. If you have no engine light, that would seem odd as well, to me anyway. Does the car shake or feel weird when you first start it up? It should have no problem going straight to high idle on a cold start.

 

[billyroku]

What stands out to me in your description is the part where you say the rpm's go up after the odd noises stop. That is not normal in my experience. On a cold start, once the car fires, it immediately goes up to a high idle of approximately 1200-1300 rpm's. Then over the next 30-60 secs it will slowly come down as it slightly warms up, down to the normal idle of about 850 rpm's.
So if your car is making odd sounds and not going up to it's high idle I would say something is wrong like it's missing and misfiring. Those things should cause the engine light to illuminate though. If you have no engine light, that would seem odd as well, to me anyway. Does the car shake or feel weird when you first start it up? It should have no problem going straight to high idle on a cold start.

[UPDATING ORIGINAL COMMENT] When it first starts, it doesn’t exactly shake the cabin, but the cold idle is very unsmooth because of that burbling (it sounds like it’s sputtering but I don’t know if that’s the correct word to use). It’s goes straight to 1500 rpm when it first starts up, it stays there for a minute or so in the process of it burbling, then after thirty seconds the burbling stops and although the rpm stays the same, the engine sounds like it’s revving up. The car never gave me the check engine light during my almost two years with it, however, I will say it did sit for several months well before I got it, I don’t know the specific time it did though. The normal RPM when it’s warm does stay normal (between 500-1000).

 

[joegr]

So, if engine speed is not increasing, what is it that you are hearing that makes you think that it is "revving up?" We really need a sound clip to be able to make any reasonable speculation.
Can you connect a scan tool and get graphs of the valve timing while it is doing this?

 

[billyroku]

So, if engine speed is not increasing, what is it that you are hearing that makes you think that it is "revving up?" We really need a sound clip to be able to make any reasonable speculation.
Can you connect a scan tool and get graphs of the valve timing while it is doing this?

I do not own a scan tool so I can’t get a graph of that.

Since I can't get the video to post here, I posted it on good ole' fashioned youtube to make our lives easier:

.
This video was recorded back in August, but since then nothing has changed. Hopefully this helps you all since voice memos will not work with me.

 

[onlyjeeps]

Oh ya, definitely sounds like i's misfiring to me. If you were to drive it right then, it probably would hesitate and act up. I can't believe it hasn't thrown a code (yet). I would take it to a reputable shop, doesn't need to be the dealership.

 

[andrewschu44]

My Cadenza has had this issue for a while (probably for less than five years). Whenever I cold start my car, in reality it’s 80 degrees cold, the timing chain clatters for at the most 5 seconds and the exhaust burbles for probably 30 seconds, then roughly smoothens out. On warm starts the timing chain clatters but no burbling. I believe my grandfather (who originally owned this before me), had the timing chain tensioner recall done, but I do not have the service records on me. Mechanic who we have been with for several years gave us three additives for the burbling, two fuel one oil, that didn’t work. I’m not sure if I have to get the tensioners done again, but if that’s the case, could it be causing the burbling. And is there a warranty for the recall that is transferable, since I am not the original owner?

Did you figure out the issue or get it resolved? I feel like I’m dealing with somewhat of a similar issue