Fuel injector size vs. electronic MPG

[silverFX]

I have increased the size of my fuel injectors. (E85 experimenting)

Now my Trip computer is telling me that my MPG is 20 when it is normally around 16.
I know it can't be true.

My question is;

"How does the car calculate MPG?" My guess is fuel injector pulse width but that is a guess.

 

[HYME]

did you ever find a answer to this question?
I would think MPG would go down using E85.
Did you use straight E85 or was it mixed with 91?

 

[silverFX]

I can only assume.

When I had the larger injectors in I can only assume the ECU calculated the MPG based on the original injector size.

With the larger injectors I was running straight E85. With E85 I was getting maybe 14 MPG.

I think it would have been easier to just use a "black box" to adjust the pulse width to the injectors. Then you could run both regular gas and E85.

I am just running 93 octane now.

 

[HYME]

are the big injectors still in?

 

[silverFX]

No

No they are not. They are sitting in my toolbox.