Newby MPG Questions (Look out!)

[Yaryaryaris]

Hi everyone,

I'm a long time MPG-head (metro Xfi's, festivas, tercels, echos, etc.) recently got a good deal on what was my modest dream car (07 Yaris HB 5-spd) only options: A/C and cruise. I NEVER use the A/C (I wouldn't use it on the surface of the son, just out of principle)...

Anyway, I got it used with approx. 35K The only "mod" it came with is a K&N air intake (it was a surprise, not told to me until I flew from Mn. to Utah to fetch the car) I figured it wouldn't hurt MPG's, and might even help.

On my way back to Mn. I drove exactly 57MPH with one other person in the car and averaged around 39MPG.

I found this VERY disappointing considering my Echo (2-dr, 5-spd) got 50+MPG's driven this way (I never got less than 45MPG with that car)

But wait, it gets worse. I realize it's winter (and Mn. has plenty of it) but I can't get this car to get anything over 35MPG NO MATTER HOW EASY I DRIVE!!! Sure, I could push it around with the engine off.

I'm an experienced max-mpg driver, never speed, slow take-offs, low RPM's coasting when possible, etc.

My research regarding this so far has been that the relevant differences between the Echo and Yaris are: weight (Yaris is heavier) wheels (Yaris' are bigger and wider) and shape (I've read the HB has more drag than the sedan)

But I've been reading here on this forum (and other accounts elsewhere) of people getting much better MPG's with my exact Yaris, and even AT models.

Questions: Could the K&N filter be negatively effecting MPG's

I also run my tires at 44PSI (yeap, it's a rough ride, but I'm all about the MPG's)

Any advice would be much appreciated. I put in a request for the stock intake available over on the FS section BTW.

Brenton

[BailOut]

Welcome to the Yaris family, Brenton!

It sounds to me like the previous owner drove the car rather hard. The Yaris' ECU "learns" one's driving style and will run richer or leaner accordingly.

Try pulling the ECU fuse in the block under the hood for 15 minutes to reset it, and then give it a few weeks to adapt to your hypermiling style.

[Yaris Hilton]

I've seen reports of over-oiled K&N filters coating the mass airflow sensors with oil and messing up the mixture. Can't hurt to clean it. There's a thread on here somewhere on doing that. You should be getting better mileage cruising like that.

[TLyttle]

I ain't supposed to say this, but I have had less-than-stellar performance from K&N filters. Previous vehicles often suffered after the K&N installation, rectified by modifying the vehicle to take a larger paper filter. Sometimes this is not possible (my Volvo 245 is next), but a little bit of backyard engineering is all that it takes to make a decent (in one case, 10%) difference to fuel mileage, without damaging performance...

[Yaryaryaris]

I went out tonight and pulled two small fuses. If I'm readin the back of the lid correctly, the ECU is the small 15 amp about half way down the line? I also pulled the 7.5 next to it in case I'm reading it wrong.

Thanks for that advice, it's very possible (likely) the former owner didn't care as much about MPG's as I do, and thus drove it "normal"

And thanks for the welcome. I'll be here a lot.

Brenton

[Yaryaryaris]

Another Quick Question: Since the Echo and Yaris use the same drive train (as far I know) might the echo have a taller final drive ratio in the manual trans? It was like this with the metros (XFi trans runs lower RPMs at cruise, increasing the MPG's dramatically)

Just curious. I would switch mine out if it was the case.

Brenton

[jambo101]

If you have your heater controls in the defrost range the air conditioner continually cycles on and off,may not make much of a difference but that combined with other factors such as oil viscosity,engine tune,tires rolling resistance can all add up to lost efficiency,my scan gauge gives me a reading in the mid 40's when doing long trips at steady highway speeds in my 08 Yaris sedan and readings in the high 40's in my 05 Echo sedan. I'd go back to stock air filter as the onboard computer may be misreading something in the filters parameters and using more gas to compensate (just a guess)
There are also some forums that take fuel efficiency to whole new levels,give em a try.
example=http://www.cleanmpg.com/forums/

[Yaris Hilton]

You don't need to pull any fuses or reset the ECU. The adaptive learning goes on all the time, and it will adjust to your driving very quickly. It doesn't affect mixture anyway, mostly transmission shift points.

[Yaryaryaris]

and here I hoped for an easy fix...:)

Doesn't the defrost button (in the center of the bottom control knob) have to pressed in to be "engaged"?

Any takers on the Echo trans. question?

Brenton

[Astroman]

Nada on the defrost button. That is for the rear window. If you use the defroster at all it's linked to the A/C. Also, the sedan and hatch have the same drag coefficient rating of .29, it's just a myth they are different.

I managed to get 44.3mpg out of my girlfriend's '09 5sp hatch, going 65-70 with a car full of my stuff (was moving from Portland back to Wenatchee) and I wasn't doing ANYTHING to save MPG, and tires were normal PSI.

Just let that ECU learn your driving style, and run some good top-tier gas in the car and it should help. I also noticed a increase in MPG switching to full synthetic 5w-20 & 0w-20.

[Yaryaryaris]

Very helpful...thank you.

Further Questions: Can I just remove the AC system, or at least the belt (or fuse?) to render the AC nothing more than dead weight on the car (I REALLY hate AC BTW)

I run my defrost all the time due to weather conditions here in Mn. so are we saying the defrost doesn't work w/o the AC system somehow? That would be a dumb thing for Toyota to do IMHO.

Tires: Just checked, mine has 195/60/15's winter style tires. Would the increased size make a noticable difference in odom. readings and/or MPG's

Great group, I'm hooked already.

Brenton

[b_hickman11]

Does the AC compressor have it's own fuse? If so maybe you could just pull it? Not for sure if everything else would still work though.

[Yaryaryaris]

Originally Posted by b_hickman11

Does the AC compressor have it's own fuse? If so maybe you could just pull it? Not for sure if everything else would still work though.

If someone knows the answer to this, and where it's located, I'll try it.

Thanks,
Brenton

[Astroman]

Someone did find the part number for a belt designed for our engines without AC. The defrost should work w/o the AC, but slower. Having the AC linked up clears the windows up almost instantly.

[Yaryaryaris]

Here's a pic of the K&N unit:

http://www.flickr.com/photos/40581861@N03/4192984839/

There's no filth or oil anywhere that I can see. The little black boxy unit with wires coming off it (MAS?) rests a little lose on the silver tube, and air probably can slip underneath it. A possible issue?

Brenton

[jambo101]

An informative previous topic on AC and the defrost and a tutorial in the first post on how to bypass the system.
http://www.yarisworld.com/forums/sho...hlight=defrost

[jonismyname]

just found this thread after pming yar yar yaris everything already posted. sorry dude. looking at the picture, that's not a kn air intake, probably an ebay critter, and probably improperly installed. the MAF would def be a concern. google "clean MAF" or something along those lines. like i said in PM, CRC (chemical company) makes a MAF cleaner that is safe to hose it down with. NAPA sells it.

for the AC, you can unplug the wire going to the electronic clutch, which will not allow it to engage. this will only spin the outer pulley on the compressor, which is very light. just cover things up if you leave it unplugged, or use a fair bit of dielectric grease. something.

[why?]

I am pretty sure real winter tires do hurt mpg by a few.