2016 Prius Making Rumbling Sound at Start

You really don't "start" a Prius. You put it in Ready mode, and it decides when to fire up the internal combustion engine (ICE). Once the ICE is fired up, it wants to go through a warm-up cycle to prepare the catalytic converter to clean the exhaust contaminants. You don't want to shut down the ICE before it completes the warm-up cycle and shuts itself down. Perhaps the first owner did not adhere to this, and it can result in engine shudder upon a cold start. This was more common on Gen 3 (2010-2015) models. You might search the Forums for "engine shudder" for more discussion on this phenomenon.

 

Indigestion? I often rumble just after I start "…braaaaaaap! (…scooze me!)" (…sorry, I couldn't resist!)

 

Welcome to Prius Chat @Quinn. Love the picture on your profile btw. You're going to find lots of strange things (compared to a more conventional car) about the Prius as time goes by. Most are regular Prius noise because basically it is an electric car that is driven by battery power. That said, the has an extremely efficient petrol engine which comes on when necessary to keep enough charge on the battery. Best of all, you don't have to think about this as the car's many computers do all the right things at the right time. Not gonna blind you with tech stuff beyond that, but in essence, there's very little to go wrong and it is generally regarded as a very reliable car with safety features loaded to the roof rack!

 

welcome and congrats!
take a spin in a new one at a dealership. if you still feel something is wrong with yours, have them take a look at it.
any warranty from the subie dealership?

 

I was surprised by all the new noises I had to get used to when I bought my Prius, but you'll soon get used to it - think of it as your Prius telling you that all is well (…or not! ) One of the nicest things I've found about the Prius is the smoothness and the quietness of the ride, although the ICE stopping when the car comes to a halt takes a bit of getting used to, however if I'm riding in any other car now, having got used to my Prius, I find most other cars to be rather noisy!
BTW Welcome to PriusChat!

 

This is my third Prius so I’ve gotten used to it.
When the petrol engine starts there is a bit of a ”rumbling” sound, that is a good word for it in my opinion.
I kind of like waiting for it to start nowdays and enjoy the rumble.

Isn’t the whole engine design different on a Prius compared to a normal car?
Some sort of Atkinson-Chekov-Daneel improbality drive?

 

I think the dylithium crystal discharge capacitor on mine has started making unusual noises, but no codes thrown up yet!

 

Take it for an Italian tune up to clear the cobwebs (carbon build up ?) and get the car thoroughly warmed up.
I stick to only turning the car off if the ICE has cut out so it's not mid cycle on one of the warm up cycles, it seems to prevent "rough" ICE starts.

 

I do the same even if it comes on when I get to work as I park up sometimes.

Once I was fiddling with my dash cam one day and the engine started up whilst I was in the garage. I turned it off and didn't think anymore of it. The next morning the car started OK, but it chugged for a few seconds which I guess was due to excess fuel sucked in at not used the day before.

Now if I am going to do that I will always press the EV button to stop it happening, luckily I usually have around 6 bars on the battery when I get home.

 

I used to get the same thing with a Mk1 Ford Mondeo I had. If I moved it off the drive on to the front of the house and switched it off before the cold start cycle had completed, it flooded the engine and the next day it would only start with wide open throttle (aka WOT) and it would chug, chug, chug away on one, then two, then three cylinders and eventually all four would kick in. Ever since that I have always run any car I've owned up until the fast idle dropped off or in the case of the Priuses, until the ICE stopped.

 

It was so much simpler before they made the automatic choke. NB: these were the things that adjusted the fuel/air mixture in carburetors before the advent of direct fuel injection BTW. Actually, we hated it back then too, but nostalgia has a terrible memory.

 

Florida is a big place. If we knew more specifically where in FL you are, maybe someone here could listen to it.

 

Last time I looked at a map it was bigger my home country!

 

What you might try to do is record the noise with your phone and upload to youtube, clyp or another service where you can share a link in a post here. The Prius does make a variety of noises that are different from other cars. The only thing I can think of is the engine will get a bit rumbly when it is charging the batteries. The only other time I hear "odd' noises out of mine is while going slowly down a steep hill in 'B'

Check your fluids, while it shouldn't be an issue at only 22,000 miles, make sure you're not low on oil, coolant, etc... I've got 50,000 miles on mine and can't say any oil is used but you never know if the last person to change the oil put the appropriate amount in.

 

So, what did finally happen?