Decreased MPG

[GMo]

I went up to the BFG A/T 285/70/17's with Bilstein's and recently averaged about 20mpg indicated on my brand new T4R. That was all mountain highway driving, over two passes. I know the indication isn't going to be dead accurate anymore. Either way, if this thing can do 20mpg for me to and from work, I'll be stoked. My Tundra was doing 15.

What's everyone else with a little lift or tire change averaging?

 

[homeyclaus]

homeyclaus........Good point.

When I first got my 4Runner, I turned the ECO light off and my gas mileage went in the tank. Recently, I turned the light back on and try to drive in the ECO range. By staying in the ECO range, my MPG average (70 highway / 30 city) has been around 22.

The light indicates when your ECU thinks it's in the most economical zone. Key word here is "thinks" - in fact when CC is on the eco light is automatically lit because it knows it's right, even when it's at wide-open throttle goosing your T4R up a hill.

This being said mine barely stays in the eco zone when doing down hills in WV along I70 and I68. Heck, I need to give it gas for it to go down the hill. I know the TE/LTD gauges give you the option of a bar display, and unless I am coasting it's only two bars inside the ECO zone. Of course, according to Toyota my 4Runner is still in the "published range" and they won't do anything.

 

[mgrande]

I went up to the BFG A/T 285/70/17's with Bilstein's and recently averaged about 20mpg indicated on my brand new T4R. That was all mountain highway driving, over two passes. I know the indication isn't going to be dead accurate anymore. Either way, if this thing can do 20mpg for me to and from work, I'll be stoked. My Tundra was doing 15.

What's everyone else with a little lift or tire change averaging?

I would be willing to bet that it is very inaccurate in your case because the truck is under the assumption you have smaller tires. A scangauge would be your best bet in knowing your MPG's

 

[GMo]

I would be willing to bet that it is very inaccurate in your case because the truck is under the assumption you have smaller tires. A scangauge would be your best bet in knowing your MPG's

Would you guess it's high or low now? I'm not totally clear on how it calculates.

 

[homeyclaus]

For some reason I thought the MPG were read off the CAN bus the same way a scan gauge would read it through the OBDII interface.

Mpg is likely calculated by the computer based on the fuel/air mix (throttle position + air mass + fuel temp + knock sensor input = injector pulse length), vehicle speed, and a rpm average.

The reason for the inaccuracy is probably a matter of the sample interval; the engine ECU is a real-time system, and calculations for user display are a much lower priority than calculating injector pulse length and timing the plugs, I'd think.

Option B is that the display does its own calculations based on the spot mpg feed from the engine ECU, and that averaging adds to the "drift".

It is most definitely not set to tire size - it's based on engine management system feedback. Otherwise mine would display 20 mpg, not 16.8.

 

[tjnaples]

114Run, we may drive like grandpa's keeping that light on and people will pass us immediately from behind from a stop, but by god it makes a big difference at the pump!

 

[1engineer]

Use the manual method: Fill up to click, record milage. Next fill up do same. After 3-4 fill ups you can take miles/gallons for each fill up to get individual tank average. Keep a running record and you will get a much more accurate number that you can then use because as you are filling up you can then put "mostly city, winter" for example and then you will know what your average is for mostly city driving in the winter. Same for summer and you can add as much detail as you want to then figure your fuel consumption during any condition, even off road. After you have done this for awhile you can then figure an average for your specific vehicle during all conditions. I do this and can tell you exactly how my vehicle is doing and spot troubling trends fairly quickly. I am a little leery of people complaining about their gas milage when they have no real baseline to compare for their specific vehicle and driving habits.

 

[homeyclaus]

114Run, we may drive like grandpa's keeping that light on and people will pass us immediately from behind from a stop, but by god it makes a big difference at the pump!

In some areas that sort of driving will get you honked at with choice words, and have others make dangerous passing maneuvers, or worse.

Use the manual method: Fill up to click, record milage. Next fill up do same. After 3-4 fill ups you can take miles/gallons for each fill up to get individual tank average. Keep a running record and you will get a much more accurate number that you can then use because as you are filling up you can then put "mostly city, winter" for example and then you will know what your average is for mostly city driving in the winter. Same for summer and you can add as much detail as you want to then figure your fuel consumption during any condition, even off road. After you have done this for awhile you can then figure an average for your specific vehicle during all conditions. I do this and can tell you exactly how my vehicle is doing and spot troubling trends fairly quickly. I am a little leery of people complaining about their gas milage when they have no real baseline to compare for their specific vehicle and driving habits.

That's the only method that works reliably. I have those logs for my vehicles, and while Toyota is unimpressed by the logs, you can pretty much tell when trouble is brewing long before it gets too expensive to fix.

 

[tjnaples]

Homey, so that was you behind me! . Driving more conservatively and watching everyone jack rabbit start to only stop a few hundred yards next to me at the same light is entertaining. So Homey to you I say good day sir!

 

[Airwolf]

My MPG computer is very close to calculated numbers. My last 3 tankfuls I have been at 19.8, 19.6 and 19.5 on the computer and 19.8, 19.5 and 19.4 calculated. My driving is 70% city with most of that at 45mph, very little stop/go traffic. I have just crossed the 3500 mile mark after 3 months. I usually "try" to keep the ECO light on, but do jack rabbit start probably more then is recommended for good MPG. So far I am very happy with the MPG. We will see how much going to 285 tires over the 265 size effects MPG in the next few months..

 

[homeyclaus]

Homey, so that was you behind me! . Driving more conservatively and watching everyone jack rabbit start to only stop a few hundred yards next to me at the same light is entertaining. So Homey to you I say good day sir!

I jackrabbit from light to light only in places like Argentina and Turkey, since not doing so will get you killed there. And I do a lot of things there that probably would get me killed here.

In northern VA, I generally keep up with traffic, and work to conserve momentum - it's all about rolling smooth. It generally doesn't work and only results in people blocking two lanes trying to nose in ahead of me.

No midwestern mosey, slow-roll, or whatever, since that sort of thing leads to heated discussions with soccer moms in Ford Explorers or Honda Odysseys who seem to believe it's your fault when they plough their vehicles into your front fenders trying to cut you off. Heck, one even thought it was my fault I caught her bashing her door into my car ... twice.

 

[mgrande]

Use the manual method: Fill up to click, record milage. Next fill up do same. After 3-4 fill ups you can take miles/gallons for each fill up to get individual tank average. Keep a running record and you will get a much more accurate number that you can then use because as you are filling up you can then put "mostly city, winter" for example and then you will know what your average is for mostly city driving in the winter. Same for summer and you can add as much detail as you want to then figure your fuel consumption during any condition, even off road. After you have done this for awhile you can then figure an average for your specific vehicle during all conditions. I do this and can tell you exactly how my vehicle is doing and spot troubling trends fairly quickly. I am a little leery of people complaining about their gas milage when they have no real baseline to compare for their specific vehicle and driving habits.

If you have larger tires that still wont be accurate. Your mileage will be off because youre new tires rotate less in the same distance than the stock tires do. Thats why I suggested a scangauge because it allows you to set your tire size.

 

[1000MPH]

Definitely check the ethanol content of your gas if you are experiencing poor mileage.
I can't get a straight answer as to which states now have year-round ethanol tainted gasoline but I think Florida does.
I'm a bit curious as to how all the little mods we do affect mileage.
Probably negligible but still curious.
Same sized tires but different brand
bug guard,
roof rack rails
hub caps
clean vs dusty (ok now I'm getting a little crazy).:jump:
I wonder if removing that front air dam from the SR5's has affected mileage.

 

[City4Runner]

Update

So this is a preliminary update for the problem I have been having.

Before any changes:
I cleared my MPG meter on my way to work and back Highway 85% and 15% city (to and from work and interstate) I was averaging 21.2 MPG. I noticed once I got into the city (back from work and farting around town) my MPG QUICKLY dropped to 17.9MPG.

Further investigation should that on the recipe from the dealer they used 5w30 in my 4runner. I changed it to Castrol Synthetic 0w20. I did not change the oil filter (primarily b/c I couldn't find it, it started raining, and I was too lazy to take down the skid plates). After I finished I cleared out my MPG meter with about 3/4 of a tank of gas in it. The rest of the miles I averaged 18.6 MPG ( for 245 miles), this was mainly city driving because I was on vacation and did not have the highway commute to work. I also forgot, before changing my oil, to check the level of oil the dealer placed in it.

In the works currently:
Techron fuel system cleaner with a tank of 93 octane with ethanol
K&N Air Filter (on order)

In Florida we are forced to have a maximum of 10% ethanol blended gas. They do not really tell the amount but anything up to 10%. They do have ethanol free gas but it is $.65 more a gallon by me in Brandon (if they have any).

Air filter currently is clean and no signs of visible issues. As my truck the only modification I placed was a bull bar on the front 6 months ago. Stock tires and stock combo.

We will see what happens... :redbrick:

 

[Quentin]

95% highway driving, rolling on stock bridgestones on a stock truck (well, I have mudflaps).

Tracked via Gas Cubby on my iphone over 15000+ miles.

 

[114run]

City4Runner...........How in the H did the dealer put in 5W-30 when the filler cap clearly states 0W-20? Then again, I had a Cadillac dealer rotate the rear 18 inch tires to the front of the car and the 17 inch front tires to the rear. Not to start a dealer bashing campaign, but - come on this is pretty basic stuff.

tjnaples.........Given my "fiscally responsible" i.e. cheap nature, I do try and drive with the ECO light on. If I want to go fast, I have other toys for that. As you mentioned, the gas milage difference is surprising.

 

[tjnaples]

114Run, I've begun to think of keeping the ECO light as a game I play. I've been road tripping the country with my new TE and would say 55-60 mph I have gotten as high as 22.5 mpg. 80-85 mph equals 17-18 mpg. Those would be my lows and highs, everything else was in the middle. Did I mention I also hate ethanol? I hope NY does not have it in the gas. And yes, BIG difference man.