Toyota/scion dealer said they haven't serviced frs yet
 

Went to dealer this morning had some questions about my frs and they said they haven't serviced any yet and couldn't answer my questions! I was like don't you have one tec that had any frs training? NO
I said my average mpg computer it's totally wrong and i reset it at every fill up.....says I'm getting 35.1 but I'm only getting around 30 when i do the math?
Service guy said it's normal to be off that much.......i was like ru serious?

He's probably serious because they are no where close to being accurate.

Yea it's more of a guideline then a scientific measurement. Pretty much the same on any car that has that system. Its good for knowing if your fuel consumption is going up, or down- but thats about it.

I'm more curious as to the math your using. I tried calculating it but not sure how far off my assumptions are. I'm using 13.2 gallons as tank size, but is the tank 100% full after the pump stops the first time or only after you top off after a few more squeezes.

When does the actual 'E' come on? I always thought it was about one gallon, but I think that's off.

I assume you are resetting your trip computer when you fill up. Then when you need gas again you fill it up, do not top off, and then divide the miles by the amount of gallons shown on the pump.

Miles on Trip since last fill up dived by gallons at fill up = Avg MPG.

Is that right?

My MPG actual vs. computer is close
 

35 mpg vs 30 mgs is what, like a 15% or so difference? That seems like quite a bit of difference not know how the calculations are done. I'm getting very close to what the computer says I am. Usually, when I fill up and am on empty (the fuel indicator light is on), I typically still have almost 2 gallons left in the tank judging by the roughtly 11-11.5 gallon "fill" up.

Join the club, first local service department I went to never even heard of the car.

SERIOUSLY.

iirc Japan was one of the places that have "86" specialists. I highly doubt US gonna follow that idea

Wow! I would be so speechless with my mouth opened. :confused0068:

To OP: FYI, my MPG computer calculates about 1 - 2 MPG higher than actual.

Could you have your FR-S serviced at a Subaru dealer? I would rather have Subaru tech's handle service than Toyota to be honest given their better knowledge of the engine platform.

You dont actually need to know any of that to find your Average MPG over a tank.

Take whatever your driven trip distance on that tank and divide by how much you fueled up at the pump and you got your avg mpg. If you fuel up the same way each time (ie topping off or letting the pump stop) your calculation should be a fairly accurate representation.

+1

:word:

Ugh if you guys are recording around 35 and getting 30 I am screwed. The highest average I have seen was around 19... LOTS of traffic driving.

Introducing a Simple Test....
 

Here is my suggestion: Go back and tell him it now says you're getting 70.2 miles per gallon. :mad0260:

If he gives you the same answer "it's normal to be off that much" you'd know that the the Service guy is off.....not your mpg computer.

That would prove your point much better.:thumbup: