3.4 TT cold start loud

I’ve got a ‘23 Limited 4X4 non hybrid. Have only used the remote start with the fob a couple times from a distance. Last night in the garage did a remote start with the fob standing right by the truck and noticed the exhaust tone is very noticeably louder at start up along with more mechanical noise from the engine bay for the first 10 seconds or so, then like a switch everything quiets down. Wondering if anyone knows if it’s just the direct injection at startup for enrichment purposes ? Or direct and port working together at startup ?
The exhaust sound is like a completely different muffler and then it goes almost silent after several seconds….

 

Think it’s just the nature of the cold start cycle. The waste gates cycle and the oil is thicker along with a higher idle rpm for a bit. Nothing to worry about as long as you have oil pressure.

 

Reason it seemed louder could have been because garage door was down. If that was case.

 

It is also direct vs port injection as you mentioned. On startup it runs direct injection for several seconds as you noted, then switches to port injection.

You can hear the difference in the below video at the 15 min mark.

 

I guess it’s a combination of the waste gates cycling and direct to port injection switching over, almost sounds like an exhaust cutout abruptly closing after 5-10 seconds.. I’ll shoot a video tonight

 

The other thing could be the blowoff valve. I know on my F150 its open on cold start and makes a whooshing sound for 5-10 seconds.

 

Every car idles at higher RPM on cold start. This is to warm up the engine and cats quickly. Then as the vehicle warms up the idle drops. Some vehicles change the idle speed more quickly than others.

 

is it anything like this

https://youtu.be/nI5uBOn6xfk

 

i havent had it do that since that morning. but then again it hasnt been in the below zero temps since then.

 

This^^^^^

 

Holy crap..!!! That sounds like a shop vac

 

About 57* ambient temperature and a cold start. You can definitely hear the engine intake sound change, but the exhaust sound is what surprised me….https://share.icloud.com/photos/044GhtlWKKMiSvBhmNHlC-xhA

 

I have the same startup noise. Lasts for 10 seconds then quiets down.
Warmup and idle drop take a few minutes.

 

This is a large bearing running dry (grease is frozen?).