Hi All

We own one of the first 400h's in the states, 23rd i believe. We are very disappointed fuel econmy. 23mpg average. Living in Washington DC we drive mostly in the city. What are the chances for getting a softwear modification from toyota to get the gas engine to turn on later, thus improving FE. I am also wondering about the number of HiHy and HH owners willing to sign a petition to get toyota to do this.

On another slightly related note is there an electric only mode modification for the 400h. I know there is one for the new prius.

thx
-Alex

Hi Alex,

Welcome to GreenHybrid.com. You might want to hold off on starting a petition until after finding out a little more about your vehicle and how things works.

I'm a Prius driver but I understand there are two models:

- 4x2 with 33/28 EPA
- 4WD-i with 31/27 EPA

Which model are you driving? How long have you had it? How many miles?

Are you driving the EPA profiles:

• City: Represents urban driving, in which a vehicle is started with the engine cold and driven in stop-and-go rush hour traffic. The driving cycle for the test includes idling, and the vehicle averages about 20 mph.
• Highway: Represents a mixture of rural and Interstate highway driving with a warmed-up engine, typical of longer trips in free-flowing traffic. Average test speed is about 48 mph and includes no intermediate stops or idling.

Before blaming the vehicle, which does happen, we need to rule out several other possibilities. You might also consider posting and working in the "Toyota Highlander Hybrid & Lexus RX 400h" forum where there are fellow drivers.

I don't have any detailed information about your vehicle and would prefer to offer opinions only after reviewing at least the maintenance manuals. But there are several things that are generic that you might start with:

1. record your mileage - there is an excellent database and you should consider putting your vehicle in and recording every fill-up. This may reveal patterns to the fuel efficiency and lead to insights.
2. separate commuting from weekend driving - top-off at the first of each work week and the end of the work week. This will let you see if one or the other is getting better or worse MPG. You'll also be able to test single changes that improve one style of driving but may hurt the other. Like the EPA City/Highway miles, keeping them separate allows easier diagnosis of the problem.
3. make your own MPG vs. MPH chart - if you have a reproducable route or cross-country trip, consider setting a target speed with the cruise control and measuring the MPG at that speed for 2-3 hours. The goal is to do your best to hold that target speed during the test. Here is my example of an MPG vs MPH chart.
4. maintenance - make sure your oil is not overfilled and your tires are at their highest rated pressure.

There are changes to driving style that can also help. For example, predictive braking (coasting to a red light) and keeping speeds in the first 2-3 miles, low-speed, neighborhood driving, to let the vehicle 'warm-up' in the morning and 2-3 miles, low-speed, driving at the end of the day to maximize use of the battery at the end of the day.

I've only had my used, 03 Prius for 9 months and my first top-off came in at a disappointing 39 MPG. Since then, I've done better, 51.3 MPG to date. The one lesson learned is there are a lot of little things that lead to good MPG performance.

GOOD LUCK!

Bob Wilson

Operation Iraqi Oil Freedom:

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My other 1500 cc car:

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Hi Alex, I suggest you also post your message on the Highlander/RX 400H group here. If there is such a thing as and EV mod, they will probably know about it.

As far as low mpg, the usual suggestions include combining your short trips to the extent possible, using the highest tire inflation that you are comfortable with, and driving 'gently' and with anticipation. A few have found that their parking brakes are not releasing completely.

It might be Prius-specific, but engine oil overfills from the factory are not uncommon, and may reduce fuel economy a bit.

Good luck with it. I test-drove the hybrid Highlander and it was pretty darned nice.

DAS

I feel for you regarding the MPG. I get 20 in my neighborhood. I realized this weekend that I need to move in order to get the EPA gas milage. Here's the scenario, I live in NYC and for most of my local trips I can't reasonably accelerate to 20 MPH before I need to slow down. That is why I get 19-21 in the city. I went to a friends house on Long Beach. I gassed up in his neighborhood, drove 10 miles round trip from his house with one stop and got 31.7MPG when I returned to his house. This was with a warm engine, 500lbs of people including me, air conditioner blasting and temp around 90 outside.
So it goes. MPG is a hell of lot better than my last SUV 9-12mpg (2003 ML500)

Plug-in battery packs are in the works. I'm waiting for the issues of the better batteries to finally be resolved before I plunk down $10,000 for an upgrade.