Help me please!

Take a close look at the rubber grommets on the pump bracket where you bolted it down. One is probably missing that. (Or it came out of the old one.)

Its purpose is to let you tighten the bolts securely but without squishing the rubber grommets, so they still absorb vibration.

 

^ This.

It's not super critical to replace but if you're still "in there" do it. I apply a little heavy grease to help hold items like these in place.

GOOD LUCK!

 

Without it, tightening the bolt squashes the rubber into a hard little puck, and it transmits crazy amounts of pump noise into the cabin. Turn the car on and instead of a Prius it sounds like Das Boot. Give a ride to somebody mechanically savvy and they'll be like "left the spacer out of some pump bracket, eh?".

 

Look under each of the bolts you used to secure the new pump into the car.

If it isn't missing under any of them, then look on your old pump bracket.

If it fell out of the old one and not the new one, you don't have to do anything.

 

Here's a visual for it. One complete grommet assembly still installed in a pump. And another rubber grommet with the metal insert removed. The metal insert is installed into the rubber grommet from the bottom. You'll see nothing from the top, as the bolt head will cover the thin tube. Look at the old pump....is it missing one?