TOYOTA Prius HSD - Manual (Page 18)

NURTURING
Filling the Tank
Fill Speed It is best to use the slowest setting (the farthest latch on the pump-handle); otherwise, the pump
could shut off prematurely giving you an inaccurate indication of "full".
Topping Off Don't! Once the pump automatically stops, don't trying squeezing any more fuel into the tank.
More causes the bladder to stretch. Too much force will result in spitting out of fuel onto the
ground. So never, ever pump more than 12 gallons.
Also, pumping too much fuel into the tank will result in gas filling up the vapor-capture canister.
That defeats part of the emissions system. So if you want your Prius to remain the very cleanest
possible, avoid ever doing this.
Important Note: As with all vehicles, repeated flooding of the vapor-capture canister cause damage
to it… leading to eventual failure.
87 Octane Gas Prius was designed to run with 87 Octane gasoline (85 in high altitudes). Several owners have
experimented with 90 & 93 Octane; however, there wasn't any improvement to MPG. Since engine
knocking is non-existent with Prius, there's no benefit in that respect either. Additionally, higher
octane may trigger an emission sensor alert. Therefore, save some money by using 87 Octane.
Low-Sulfur Gas Without the loss of performance or power, low sulfur gasoline helps to reduce emissions by
preventing efficiency loss within the catalytic-converter (a pollution control device) due to sulfur
build up. This also extends the life of the emission components. All gasoline sold in the United
States was mandated to be low-sulfur beginning January 2006.
10% Ethanol 90% Gasoline blended with 10% Ethanol, better known as E10, will not harm any part of the Prius
fuel or emission system. Owners in Minnesota, where E10 is mandated by law, have used this type
of fuel in their Prius for many years without experiencing any problems at all. So there is no need
for concern.
Empty Don't ever run out of gas!
Not having the engine available makes driving a Prius using just electricity very risky. Without
gasoline it is very easy to push the motor & battery-pack beyond the tolerances they were designed
to operate. The battery-pack is never supposed to be fully depleted, that shortens its life. Also,
without gas there's no way to prevent certain mechanical & electrical components (like the fuel
pump) from overheating. Since Prius can go quite a bit further between fill-ups than most vehicles,
there's really no reason you should ever run out of gas anyway. But if you do, drive very slowly
and just enough far to get out of harm's way then stop. Don’t keep driving.
Another Gauge When there is less than half a tank of gas remaining, the gas gauge is less accurate due to the
flexible nature of the bladder within. A helpful measurement alternative is to base refill timing on
the mileage you drive. Just reset one of the three odometers (A, B, or the one on the multi-display)
every time you fill the tank.
450 miles (725 km) in the summer and 400 miles (644 km) in the winter is a good distance to start
with. You'll quickly figure out what works well for your particular needs.
Prius User-Guide 18 of 54 Last Updated: 9/01/2007