Designed a new UI for my roommate's app

So my roommate made an app a while ago to replace his car's broken gas gauge. He hates UI design, and told me he would do it later. I personally love UI design, and he still hasn't done anything, so while I was bored the other day I mocked up a new UI for him. Now, here's what the app looks like currently:

Rlsi6_medium

And here's how I redesigned it:

R96fb_medium

I'd love to hear if you like the design or not, and what you would change! Let me know.