88 octane - loss of MPG

i like to check the easy / obvious things, instead of ignoring them and going for the expensive/harder stuff.

 

thanks for pointing those out

 

Great fix, now get another tank of 88 again just to make sure.

 

Wow! Four pages of opinions and no one got close to the problem but there were a couple of honorable mentions...

Original post:

First sliver of light quickly forgotten:

An attempt to add logic:

Correlation is not causation:

Another voice of reason:

Victory after recognition of a rather common problem:

 

That's because when someone mentions the 12v battery the mister know it alls start ragging on them
that there are better ways to do it and other things to check!!!! And they get tired of it!
Me, I just block them!

From what I've read in Prius chat for the last almost 4 years is that a weak 12v battery causes a lot
of different problems to pop up, that aren't really the problem.

And it's extremely easy and quick to check it!

 

I think it was misdirection caused by an initial assumption that could have made a donkey out of any of us. I learned early in my career when all diagnostic steps pass but the problem persists, it is time to throw out the assumptions and start over. Easier said than done but if its midnight at some remote industrial plant and you are it, you reset and resolve.

I will admit years ago I was a doubter that a bad 12v battery could draw enough charging energy to cost significant mpg. I do recognize that fact these days even though I have never personally seen it. It is kind of amazing the inverter's dc to dc converter can safely source so much energy and the 12v battery can burn it up just as fast.

 

Before the invention of the catalytic converter, cars typically had 8% Carbon Monoxide in the exhaust
That's 80,000 ppm Carbon Monoxide = Deadly gas.
Ethanol addition reduced that extreme CO emission by about 25-30%.
This is the main eco-benefit of ethanol, and that was of some importance before cat converters came about.

Today the CARB catalytic converter on the Prius makes about 0-ppm CO, with no need for the ethanol.

In fact, if I recall, CARB was originally a bit reluctant to mandate ethanol, due to worse evap emissions, but Ca. finally decided it was more expedient to accept the national E10 RFG ethanol mandates.. My guess you probably will not find E15 in Ca. nor my RFG area. Why not? for the obvious reason of higher (evap) emissions.

As far as UK, I don't know what the cars/trucks have on them re: Cat converters. Also in USA, compared to the much higher gaso sulfur of the 1990's, we now have near zero sulfur gasoline, which really super-charges the cat converters pollutant removal activity, whereas sulfur is a cat poison.

 

I came on this forum to see if 88 gas would hurt my Prius. The manual says I can use it but I can’t believe your gas mileage is so low with any fuel. My 2012 got better than yours on reg gas and my newer 2021gets much better and I live in the hills of WV. I avg 49 in town and 58 on a recent trip to the beach. Maybe there is something wrong with your car.

 

you really can't compare cars, drivers and locations when it comes to mpg's YMMV

 

He fixed the problem. It is good practice to read the comments. 88 octane had zero to do with it.

 

Since the thread is open again...........
I think that the fuel stations that do this should be FINED for deceptive practices:
88 octane should be fine ......IF......that was the only factor.
Alas, E15 blends seem to be prominently labeled as 88 octane and the fact that it is E15 is only mentioned in the fine print.
While E15 is not likely to cause any problems with one tank full, over time it could cause damage......especially in older cars.