Loud noise right after start up

I think I read a post on this somewhere but can't seem to find it. My 2015 TRD Sport 4x4 auto 4 dr makes a loud noise right after startup in the morning. It kind of sounds like a door or flap or something opening or closing but it is really loud. Nothing seems wrong but it it just TOO loud for me. Anyone know what this is?

 

Might help if you can take a short video (w/sound) of it happening and post it here, any check engine light? What's your mileage?

 

I will take a video of it when I get back in town next week. No light no problems. On cold start it sounds like a loud clap or something. Just one loud sound almost like a door is being sucked closed by a vacuum or something.

 

Hi Flafos, I have a 2015 TRD OR DCSB and I have a similar noise to what you're describing. It's within the a few seconds after start up, I'll be interested to see what others have to say. I'll see if I can capture the sound on video as well.

 

sounds like the air injection pump.

Does it sound like a turbo or high pitched whine?

if so its completely normal.

 

Are all the neighbor cats ok?

 

That's where my money is. It is normal, but only because the pumps on these trucks fail, and it means the pump is getting ready to give out. It doesn't mean it's going to happen tomorrow, but it will happen eventually.

 

My 2014 does doo. It's done that ever since it was new. Not sure what it does, it it's for emissions or it pressures up the manifold. I can hear the little door/check valve closing after about 10 seconds on a cold startup

 

I've found the answer on here before because it worried me as well when I first got mine. Its some pump having to do with smog or some bullshit... Totally normal guys

 

My 2015 V6 PreRunner Tacoma makes a sound that resembles a person clearing their throat about 25 secs. after starting engine stone cold. Lasts for maybe 1/2 sec. Seems louder in cold weather. Now that it's close to 90F by mid-afternoon, the noise is more muffled if 1st start of day occurs then.

 

the turbo / wind noise on start up is not stating that its failing, its just functioning like normal. It does not mean the pump is going to give out.

And its not the pumps that fail, its the shitty piece of foam that degrades and gets clogged in the vanes of the pump / the valves causing them all to fail. Remove the foam and put a 1inch uni crank case breather on the inlet of the pump and never have the issue.

 

what about a 'winding down' noise for about 2-3 seconds after turning the truck off?

 

Yea I hear it when I shut mine off too. Sounds kind of like a dust buster or something, just for about a second.

 

same thing, air injection pump that purges the system on shutdown.

 

So is this air injection pump for performance, or is it for emissions only?

 

Emissions.

 

Wow, thanks guys! It's nice to know i'm not the only one with these odd noises at start up and shut off! I feel so much better.

 

Door flap opening / closing is not the injection pump.

 

Good question...haven't seen them lately, maybe that coyote in the neighborhood has something to do with that though.

 

Does it sound like this? https://youtu.be/QvtCN8PxdAA