What do I enter for small savings account intrest with no 1099 received for FEIN ?

Just enter it "as if" you did receive a 1099-INT. Note that when entering it, you're only asked for the name of the institution that paid it, and not any FEIN number of that institution or anything.

 

As Carl notes above, you'll simply go through the same path as if you were entering your information with a Form 1099-INTand all its relevant information, entering any information you have.

 

To enter interest without a Form 1099-INT in TurboTax Online:

 

1. Open TurboTax Online
2. Select Tax Home in the left pane
3. On the Hi, let's keep working on your taxes! screen, select the dropdown to the right of Income & Expenses
4. Select Let’s get started, Pick up where you left off, or Review/Edit
5. Scroll down and select the Show more dropdown to the right of Investments and Savings (1099-B, 1099-INT, 1099-DIV, 1099-K, Crypto)
6. Select Start or Revisit to the right of Interest on 1099-INT
7. On the Your investments and savings screen, select Add investments
8. On the Let's import your tax info screen, select Enter a different way
9. On the OK, let's start with one investment type screen, select Interest, then Continue
10. On the How would you like to upload your 1099-INT? screen, select Type it in myself
11. Type in all available information 

See the TurboTax Help article What if I didn't get a 1099-INT from my bank? for an alternate entry procedure.

@rickrichards1