[qwikrex]

Hey guys, new owner here. First foray into the Italian car world. Anyway picked up a 2016 4c spider last night. Has about 42k miles on it. So far I’m liking it. On the drive home though I noticed a weird rattle like noise under hard acceleration. Only from like 5k rpm and on. And only really noticeable in 3rd and sometimes 2nd gear. Like if I put the car in third or second and let rpm’s settle to around 4k ish rpms, if I go wide open throttle, when it gets to like 5k the rattle starts then goes away when I let off the gas or shift. Not sure if it’s a loose bolt, or pinging, or the transmission? Any ideas. I took a short video of the noise. You can hear the rattle shortly after I start accelerating in the beginning of the clip and also rightbefore the end of the clip.

Alfa 4C high rpm rattle

youtube.com

 

[Max Tayant]

Sounds modified? I’d check exhaust for tightness

 

[qwikrex]

Sounds modified? I’d check exhaust for tightness

Exhaust seems stock visually. Plus I’d figure if exhaust were loose it would rattle a lot more and in every gear, not just 2nd and third no?

 

[AlfaRomeoCares]

Hello there,

First, congratulations on your new vehicle! We do recommend that you reach out to your local dealer regarding the rattle noise for assistance. They are in the best position to diagnose. Should you choose to go that route, feel free to message us for extra support.

Lex
Alfa Romeo Cares

 

[Alfanut]

@qwikrex , Do a search for the rattle noise you get before third cog failure to check it isn’t the same as that. Hoping it’s not. It’s very difficult to locate the actual source of rattles due to the sound bouncing around the tub.
Edit: Never mind doing the search, here’s a link to it.
Transmission rattle!! 3rd gear wheel failure..

 

[Brian Barrett]

I bet its an exhaust rattle of some type - maybe even a split weld on the muffler or down pipe and its a vibration type buzz rather than something more serious. That said it could be a bolt or nut rolling around on the floor !!!!

 

[Max Tayant]

Exhaust seems stock visually. Plus I’d figure if exhaust were loose it would rattle a lot more and in every gear, not just 2nd and third no?

Show us what you got

 

[qwikrex]

@qwikrex , Do a search for the rattle noise you get before third cog failure to check it isn’t the same as that. Hoping it’s not. It’s very difficult to locate the actual source of rattles due to the sound bouncing around the tub.
Edit: Never mind doing the search, here’s a link to it.
Transmission rattle!! 3rd gear wheel failure..

Yeah, that’s one of the first videos I compared lol. It seems in that one, the rattle is continuous as he drives normally. Mine only does it under hard acceleration. And it does it both in second and third. Not ruling it out just yet, but it would seem that issue seems a bit different.

 

[qwikrex]

Show us what you got

I’ll have to try and get some up close pics

 

[Alf Alpha]

Another vote for a split in the exhaust from me

 

[H Quantum]

I would also look at this thread, could be a overboost situation:

4C Clone ECU - Wastegate sounds under high boost

Hi Guys, Has anyone with a clone ECU encountered any sounds like the ones in the video below? Sounds like wastegate chatter, https://streamable.com/oudys I'm getting this in every gear from 3rd onwards from about 4500 RPM and above. It's most noticeable in 4th,

www.4c-forums.com

 

[qwikrex]

I would also look at this thread, could be a overboost situation:

4C Clone ECU - Wastegate sounds under high boost

Hi Guys, Has anyone with a clone ECU encountered any sounds like the ones in the video below? Sounds like wastegate chatter, https://streamable.com/oudys I'm getting this in every gear from 3rd onwards from about 4500 RPM and above. It's most noticeable in 4th,

www.4c-forums.com

Thanks for the link, just checked it out. My noise doesn’t really sound like wastegate flutter though. Mine is more of a metallic sound.

got some better videos with rpm:

Alfa acceleration rattle 2

youtube.com

Alfa acceleration rattle 3

youtube.com

Alfa accel rattle long

youtube.com

 

[Alfanut]

Check the Y joint where the exhaust branches into two. Also the insulation on the firewall has been known to loosen and rattle.

 

[peterA116]

Lower likelihood but DI makes a lot of noise and a failing DI pump will make more of a rattle, first at high load and ultimately at lower loads. I don’t really hear that noise here per se but my noisy DI pump was replaced at 3900 miles. The transient nature would be more suggestive of an exhaust crack.

 

[Flash]

it happens when the car is under full boost. Sounds like turbo noise to me.

 

[qwikrex]

So I pulled the bottom tray just to take a look. Everything looked ok for the most part. Although I did find a heat shield right under the turbo, on the catalytic converter, and it was fairly loose. Not sure if this is normal as I didn’t really see any way to tighten it? Here’s a video of it.

 

[4Canada]

That heat shield won't likely cause a rattle, unless it is too low and touching the bottom belly pan perhaps. There's a fine line for it melting or rubbing!

I haven't been able to listen closely enough to your videos to pick this up (mainly at the office - they tend to frown at automotive noises coming from offices!), but is it just at RPM that it happens, or does it correlate to speed as well? i.e. at a constant speed, you could be in 3rd gear high RPM or 5th in a low RPM - does the noise go away in 5th or stay if the speed is not changed?

I ask because I had a very disconcerting rattle at speed which turned out to be a tiny pebble embedded in the soft material under the car and banging on a structural member as the airflow caused the panel to flutter slightly over a certain speed. You may not have the same problem but pointing out that noises seem to be quite amplified in the 4C when you are sitting inside a large drum.

Hope you find your culprit!

 

[qwikrex]

That heat shield won't likely cause a rattle, unless it is too low and touching the bottom belly pan perhaps. There's a fine line for it melting or rubbing!

I haven't been able to listen closely enough to your videos to pick this up (mainly at the office - they tend to frown at automotive noises coming from offices!), but is it just at RPM that it happens, or does it correlate to speed as well? i.e. at a constant speed, you could be in 3rd gear high RPM or 5th in a low RPM - does the noise go away in 5th or stay if the speed is not changed?

I ask because I had a very disconcerting rattle at speed which turned out to be a tiny pebble embedded in the soft material under the car and banging on a structural member as the airflow caused the panel to flutter slightly over a certain speed. You may not have the same problem but pointing out that noises seem to be quite amplified in the 4C when you are sitting inside a large drum.

Hope you find your culprit!

Thanks for the reply. Doesn’t seem to correlate with speed. Just with load mainly. It doesn’t rattle at all unless the engine is under load. I can go through the entire range in all gears and not hear a rattle. It seems to be most repeatable in 3rd gear if I’m anywhere in the range of like 4-5k rpm. If I mash the gas in that range it will rattle most of the time as boost reaches max pressure. I’ve also been able to hear it in second and 4th, just not as often.

 

[qwikrex]

So I looked more into the history of the car, and in one ad it states that it has an Alfa works stg1 tune. But I pulled the ecu and there’s no Alfa works badge or markings and it looks oem. So I dunno if maybe it had a tune at one point and maybe stock ecu was swapped back? Anyway to tell what map is on there? Also I changed the plugs and it looks like it had a set of Brisk iridium’s. I switched out to oem but no difference.

Anyway, Here’s the best recording I have of the sound so far. Happened very repeatably on my drive last night. In 2nd-4th gear under part throttle and full throttle acceleration. Weird part is this morning I took a drive and I could only induce the sound a couple of times and it wasn’t as severe. Morning was slightly cooler is the only difference I can think of. Does it sound like possible pinging/detonation? Wastegate rattle? I’m really at a loss on what it could be lol.

Alfa rattle

youtube.com

 

[Jwdm]

My Alfa Workshop tune has no markings on it. Looks just like stock - it just has different programming.

Jeff