What happens when I run too much ethanol?

Car is stock for now. I sometimes run ~E30. I notice the LTFTs going up, but not that much.

I was told not to run more than E30. What is the first sign of running out of fuel? The LTFTs or low fuel rail pressure, or AFR at WOT??

Just wondering what to what to look out for.

Thanks!

 

I'd be guessing fuel trim should go up and possibly set a p0171 code. Not sure what effect it has on non FlexFuel fuel pump and related items long term.

 

I run between 30 and 40 percent. However, I have an E30 tune. You can run into low rail pressure, esp in colder climates.

 

I'll be tuning this engine myself. I'm sure I can get the LTFTs back in line. Sounds like I should log fuel actual and desired rail pressure. (Maybe fuel pump duty cycle as well.) When the actual pressure can't keep up, it's time for more fuel pump.