proposal for mandatory/copy & paste fuel economy questionnaire

oh dear god... Anal-retentive much? (sorry, it just seems like an interrogation, not a questionaire)

How about simplifying this list to the stuff that has the most impact?
1) outside air temp
2) tire pressures
3) type of driving?
4) has it always been like this or has it changed recently? If it changed, what else changed around the same time? (like an oil change)

The other items may save a few tenths here and there but air temp and tire pressure seem to be the biggest factors other than the type of driving and/or something broken.

 

One could always go to fuelly.com and set their car up there. Record miles, gallons, price and any other data you want. Then just post the badge on the sig line. that way, the whole world can see your mileage, eh.

 

Something like this could help to get to the bottom of a MPG issue... but,
* It's use would be optional, not mandatory
* It should be a Sticky for continual access
* It should be applicable to both Gen II and Gen III cars
* Questions should be short and sweet

12v battery, air filter/MAF, and alignment issues can affect MPGs.

Might want to add:
How old is your 12v battery?
What is the voltage reading of your 12v battery after sitting over night?
When is the last time your ICE air filter was changed?
Have you inspected your MAF sensor for build-up?
Does the car tend to pull to the left or right when driven on a level road?
Do your tires show any asymmetrical or unusual wear patterns?
Have you heard any scraping or metal-on-metal sounds from the brakes?
Are you using any kind of front grill air blocking?
Do you have a ScanGauge or other after-market gauges?

What is your political affiliation, and what is your mother's maiden
name?

 

It might help to start with the general and work toward the specific - a few questions about key areas, then use the response as a guideline for what to ask next. Save the fingerprints, blood tests, and dna samples for hypermilers.

I think most people who complain about mileage are just looking to hit the EPA 50mpg target (not 70+). And I think that's easy with the right tire pressure and air temps, assuming the route isn't unusually short or hilly or something. So I think it's best to start with those and not go super deep unless there is demonstrated interest.

 

Something like this that I'd put together at GreenHybrid?

* * * * * * * * * * * * * * * * * * * * * * * *

Prius FAQ [V02.00]

Index

1) Definitions and terms
2) Driving for MPG
3) Handling (for new owners)
4) Maintenance for MPG
5) Maintenance for Long Life
​

FAQ Body

This FAQ is meant as an introduction to the Prius, not the last word. The 'Learn' section of GreenHybrid.com has more detailed articles and use search engines to find more detailed and current reports. It is specific to the Prius hybrids and these guidelines may not work well with other hybrids.
​

1) Definitions and terms

1997-2000 Model - NHW10 was first generation sold only in Japan but may be found in other Pacific countries. For a detailed description of the first generation, hybrid drive system:

John's Stuff - Toyota Prius THS Presentation 1
​

2001-2003 Model - NHW11 second generation known as 'Prius I' in GreenHybrid.com mileage database. Also called 'Prius Classic.' It has a small rear spoiler with an air-gap that reduces drag at highway speeds.

2004-current Model - NHW20 third generation known as 'Prius II' in GreenHybrid.com mileage database. A hatchback with a gap-less, rear spoiler, it has advanced warm-up, improved battery, improved transaxle, limited electric-vehicle capability and lower drag. For a more detailed technical description, the following links provide excellent introductions to the Prius II (NHW20) model:

John's Stuff - Toyota Prius - 2004 Tech Presentation 1
​

ICE - internal combustion engine. On Prius, a 1500 cc, Atkinson engine with extended intake valve opening to reduce compression ratio to 8:1 while expansion ratio remains 13:1.

MG1 - motor generator one built into the transmission provides engine starting, non-moving electricity and balances the engine torque in the electronically controlled, continously variable transmission (CVT).

MG2 - motor generator two built into the transmission provides forward traction, regenerative braking and reverse gear.

PSD - power split device is the planetary gear in the transaxle that couples the engine, MG1 and output drive train feeding the final reduction gears and MG2. An operational model that shows operation is available at:

http://eahart.com/prius/psd/
​

pulse and glide - a type of high mileage driving that involves accelerating to a target speed and using instruments to gently feather the accellerator to let the car coast down to a minimum speed with the ICE off. In one controlled test, an NHW20 and team of drivers achieved 110 MPG over a 14-mile loop.

stealth mode - to drive on electric only power. The NHW20 models can be modified with an electric vehicle mode switch. In all others, this is achieved by low speeds and gentle accelerator pressure.

THS, THS-2 - Toyota hybrid system, version 1 and version 2. The following Toyota engineering paper provides a detailed description of its performance and operation:

TOYOTA: Company > Technology > Introduction​

transaxle - the combination transmission and differential in the front-wheel drive Prius. Attached to the side of the ICE, it houses MG1, the PDS gear and MG2 and has output shafts for the front wheels.

"THE PRIUS THAT SHOOK THE WORLD" - this is a 105 page, PDF book written by Hideshiitazaki and translated by Albert Yamada and Masako Ishikawa. This unpublished book is the history of Prius development.
​

2) Driving for MPG

Try to preserve vehicle momentum instead of regenerative braking and startup: brake early and coast to a stop light just as it turns green; modest speeds; follow but do not tailgate large profile vehicles.

In cold weather, use a warm-up route at low speeds if possible before higher speeds. The warm-up route is long enough if the engine auto-stops at the last stop sign or light. Warmer weather can use a shorter warm-up route.

When approaching destination, drive the last 1-2 miles in electric only or stealth mode to maximize trip MPG.

Try to chain trips to minimize cooling between each destination.

Minimize speeds into a headwind or try to follow large vehicles without tailgating.

Keep your weekend MPG separate from your standard weekly commute MPG by topping off Monday morning and Friday evening.

Techniques that improve commute MPG need to be tracked as single variable changes.

Use cruise control, if comfortable with it, to minimize fuel-wasting speed variations.

In summer, park where it will be shaded and in winter, in a sunny place.

When you can, back in to park while the car is warm and it cost almost no gas. On the next trip, you will be able to drive off directly into the warm-up phase without the delay of having to back-out. Note, backing out a long driveway will shutdown the ICE, it is normal. It will restart once stopped or put in "D".

There are On Board Diagnostic (OBD) scanners that provide the additional instrumentation used for more efficient driving.

Turning off the engine requires the car to come to a complete stop and going to "P" to restart. This makes your car into a road hazard unless already stopped at a light.

During warm-up, coasting in "N" cuts the idle fuel burn in half. With the engine automaticly off, coasting in "N" provides the lowest energy coasting. However, if the ICE is running, coasting in "N" blocks electric mode and burns extra fuel. Practice use of "N" before trying it traffic.

"When it starts to look like it's time for a fill-up, . . . go the whole length of [your] commute scoping out all the gas prices for a day or two before picking a station to fill up at. [You'll] usually manage to get gas at $.15 or $.20 lower than the highest rates out there." Leahbeatle.
​

3) Handling (for new owners)

The North American fuel tank has a flexible bladder to minimize gas fumes but this means: (1) the tank volume can vary and (2) the mpg calculated by dividing the odometer mileage by the gallons can disagree with the mpg on the multi function display by more than 5 mpg. Also, avoid overfilling the fuel tank with gas all the way up the filler tube as this has caused several $1,000 fuel tank replacements.

The mechanical brakes are quite ordinary because the regenerative braking is handled in the transmission. Because of regenerative braking, your brake shoes tend to last 3-4 times longer than ordinary brakes.

The engine oil is just like any car and easy to change yourself or at discount places. Just insist that they not overfill it. Have them take out the excess until they do it RIGHT or you'll pay in lower mileage. The optimum level is 3/4 between the fill marks.

Get a tire gage and/or fill with nitrogen. Keep the tires as hard as possible, 42/40 works for most tires but always ask. The front tires need to be 2 psi harder for proper handling and best ABS operation.

The B mode is used for additional engine braking going down long, mountain grades. You have to press the button to move it into to B and can do this while driving. When done, just move it back to D for better MPG.

If you ever feel the car is "running away," put the car in "N", at any speed, and the car will coast and you can brake to a stop. If you can, keep the car running and take a photos of the accelerator area.

If you run out of gas in an NHW20, ". . . the car upper dash lit up with warning lights galore and the gas pedal stopped working. The specific lights were the large exclamation point in a triangle followed by the (!) light and the VSC light and the image of the engine" but no "OUT OF FUEL" indicator. You can drive a short distance with the "WARNING BATTERY DISCHARGE" light at a slow speed in electric mode directly to a gas station. Monitor the battery charge level and stop before it fully discharges . . . AAA can bring you some gas and this avoids a tow. Once filled with gas, the errors will clear. From 'Mr. Bean'. (NOTE: The transaxle oil pump runs from the ICE so minimize stress.)

Sometimes running out of gas and multiple attempt to start the car or other conditions may cause an error code that keeps the Prius from starting. Once and only once, you can clear the codes by disconnecting the negative auxiliary battery terminal for ~10 minutes and possibly restore operation.

Those who live in snowy, winter climates should mount quality ice and snow tires (marked with a snowflake in a mountain) in the winter season. On very slippery road and winter conditions, the 2004-2006 model year Prius with OEM or non-winter tires, the traction control can leave the car unresponsive even with the accelerator pressed to the floor. It does this to prevent useless tire spinning and transaxle issues. More recent Prius ECUs have an improved traction control system that will 'pulse-spin' the wheels in super slippery, icy conditions.

The optional, Vehicle Stability Control (VSC) is an electronic system designed to help the driver maintain steering control with hard steering. The standard Traction Control (TRAC) cuts power to prevent wheel spin with hard accelerator. The standard Anti-Lock Brakes (ABS) prevents a wheel from locking up with hard braking. All three systems require quality tires designed for the road surface, either paved, water, snow or ice covered.

Backup is a silent, electric operation so the NHW20 model issues a "beep" in the cabin to alert the driver when backing up. But a beep inside the cabin does not alert those outside the car and can annoy the driver. This thread started by David Gillett explains how to disable the cabin, backup beep.

When running in electric vehicle mode, speeds 1-42 mph, the motors are very quiet and inattentive pedestrians and the blind may be startled as you approach. Pay special attention in parking lots and around pedestrians at slow speeds.

Congress has legislation pending to put noise makers on hybrid electric vehicles. However, the Prius Fatality Accident Rate is half that of all vehicles as reported by the NHTSA using the Fatality Accident Reporting System (FARS) data.​

"Check engine" light indicates something is wrong even if it is a minor problem. If you do not have an OBD scanner, it is best to drive or have the car towed to a Toyota service center and have them read the codes. Turning the car OFF and ON three times can sometimes clear the indication and code but it is better to know what happened.

In the NHW20 Prius, a maintenance required light will come on after 5,000 miles indicating it is time to change the oil. This can be cleared, check the owner's manual.

There is an enthusiastic community dedicated to Pulse and Glide driving. However, it is not required to get better than EPA mileage.

One good technique is to avoid speeds at or transiting 42 mph, the boundary between hybrid-mode where the ICE cycles on and off by itself and gas-always mode when the ICE runs all the time. My preference is to avoid the speed range 39-45 mph and either cruise slower or faster than this speed range.

ICE efficiency appears to fall off at speeds above 65-70 mph. Try to cruse at or below 65 mph by following, not drafting, large, slower traffic.

To minimize the risk of someone reading it out of the navigation computer, set your "Home" and "Work" way-points to public landmark near but not on either the real "Home" or "Work." The real addresses should come from you, not the navigation computer (or the registration and insurance cards in the glove compartment.)
​

4) Maintenance for MPG

Keep tires at maximum with 2 PSI more in front than rear for better handling. Stock tires are often run at 42/40. Recheck pressure at least every month with a trusted tire gage. Reportedly nitrogen filled tires may not require monthly pressure checks.

Keep ICE oil at 3/4 between 'empty' and 'full' to minimize ICE splash energy losses. Self-changers buy 4 Q/L, put three in and use the 4th as a topper in case the oil level goes down before the next change. Synthetics are OK but we lack empirical data comparing oils.

The transaxle oil is good to ~30k miles in the NHW11, 2001-03 Prius, and ~60K miles in the NHW20, 2004-current, before the viscosity drops below 15% of the OEM levels. The NHW11 uses Type T-IV and the NHW20 uses Type-WS. Amsoil ATF tests revealed excessive copper contamination, do not use.

In dusty areas, use a shorter change interval because there is no filter. The NHW11 has a pan that should be dropped, the magnet inspected and wiped clean. The NHW20 has no pan. There is about a 25% dilution from inaccessible drain oil and contaminants.

One of the best introductions to Prius tires is complemented by the Consumer Reports tire summary. Expect to spend more time researching and shopping for tires than just driving into a local store.

Year round, an engine block heater saves ~50 grams, ~1.8 oz., each morning for the NHW11, 2001-03 Prius and some savings for the NHW20. This is the difference between 52-54 MPG and 60-62 MPG for a 10 mile summer commute. Ken@Japan reports the two hour electricity cost is about half of the fuel cost.
​

5) Maintenance for Long Life

In high humidity and corrosive areas, check the brakes for rust frequently, including the inside of the rotors, to avoid binding and uneven rotor wear problems.

Make sure after-market electrical devices cannot drain the auxiliary, 12 VDC battery from unexpected loads. Normally the cigarette lighter is 'OFF' when the ignition is in lock position.

When jumping a dead 12 VDC battery, check and double check the polarity since a reverse connection can fry most of the expen$ive control computers instantly.

A Mazda Miata battery can replace the 12 VDC battery provided an adapter terminal kit is gotten for the smaller sized terminal, Japanese connector.

Keep the filters clean or replace frequently.

Fleet reports suggest the NHW11 models may need to have steering assembly checked. There is an extended warranty associated with the NHW11 Prius for a steering problem that gets a steering wheel shake ". . . 10 Hz oscillations turning the wheel in my hands about 10 degrees. . ."

Year round, an engine block heater saves nearly 100 ml. of gas each day due to faster warm-up. The only known source is Toyota of Canada, part C0140 00885, and it is difficult to install due to location of the receiver on backside of ICE. Avoid coolant heaters because of the lack of usable ICE coolant ports. Thanks Ken and our Japanese friends.

Use Rain-X to minimize use of windshield wipers and keep rear view mirrors clear.

Clean the throttle assembly every 30-50,000 miles for butterfly soot and sticky gunk. It tends to get sticky in cold weather but can cause starting problems any time of the year.

The Prius navigation unit can at arbitrary times, sound a "music box" chime after some way-points have been entered.

If you are down to your last key or key-fob, buy a replacement from Ebay and 'teach' the new key or key-fob to your car. If you lose the last key or key-fob, an NHW11 will require replacing the $1,600 ECU. For the NHW20, tell your Toyota service department about "TSB SS003-02".

"Put the Odometer in ODO mode (as opposed to TRIP 1 or 2), turn the car off, and then hold the odo button in while powering up. The odo will then cycle through a test pattern and when the miles driven reappears, the Maintenance light is reset." - Jeffrey N. Denenberg, 08/28/2007

There appears to be an intermittent problem with the plastic covers on the front seat hinges that can "squeek" while driving. It can be fixed by having the plastic cover(s) removed and either 'heat forming' or plastic removal to keep the metal seat parts from rubbing on the cover.

​

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
If you would like to see a change to the FAQ, please start a new thread and quote the part(s) you want changed and the modification. This gives the community a chance to discuss the proposed change and if there is a consensus, then add the consensus update to the FAQ and increment the minor version number.

Now if someday, a change is needed and I am no longer around, whoever wants to 'take over' editing of the FAQ can make version "2.0" and tag it onto the FAQ thread. This provides a clean boundary yet leaves the historical version around for reference.

Thanks, Bob Wilson.

 

My recommendation is make an outline ... and start collecting short bits into the outline. Eventually, it will reach a point of 'maturity' and then it is sticky-time.

One recommendation is close the thread too. Let folks posts in 'draft' threads suggestions or changes but the author has to merge them in. Also, give credit.

GOOD LUCK!
Bob Wilson

 

If you want to take this direction, the "questionaire" needs only one question:
"Have you attempted each and every item described in the 'Hypermiling for Extremists' section?"

 

And if anyone says, "no, I haven't read that and done everything in it", then you can say, "well, we put a lot of time and effort into writing it, and don't appreciate when our efforts are ignored, so we're not going to help you".

 

It's kind of like going to the doctor and having them hand you a stack of books on physiology...

People post threads about their mpg issues because they think some of the "experts" here can figure it out. If they had the skills and desire to figure it out themselves, they wouldn't bother posting.

 

creating a form that can be filled out would be the only way to get this done and that is a great idea, but it will fail on so many levels.

1) people want instant answers, instant results. to fill out the form does require collecting date beforehand.

 

Well, I for one will offer assistance to anyone, and if they don't provide enough info, I'll say so. There's enough evidence that certain things have a much greater impact than others, and it shouldn't take an hour-long examination to check the obvious stuff.

 

well Tom, so will i (12,000 posts should attest to that!!) and like any improvement, if it helps one person, then its a good thing right?? and a start in the right direction.

i think in any large organization (as this site has become) managing the ever growing piles of data in different threads is a balancing act of daunting proportions.

we always are interested in the new posts, but at the same time we want to preserve the great info in the archives as well. a well put together FAQ touching on the basics is a great way to do it, but getting people to read it might be tough.

a linked form is probably the best way to do it, separated by major topics, broken down into nothing longer than two normal pages.

so who wants to take that on??

 

I wouldn't call myself a newbie in the true sense on this forum but definitely one compared to you experts. It's a good idea what you are discussing but more often the problem I face (and I'm sure others) is finding out answers for things that are already in the forum somewhere. Doing a search does not always lead to the right thread. So, people end up starting a thread (for valid reasons). To prevent this over flood of information, developing a sticky/master thread for every common question would be quite useful. Eg. say in fuel economy - break-in driving tips and expected mileage, common reason for low mileage, tips for improving the same (tire pressure, heater usage,etc), etc etc. My two cents.

 

This was suggested almost a month ago but no addition to the list of questions in the sticky yet. Administrator?