Do engine tolerances affect mileage?

[jecht]

I have an '07 S. I got in a car accident with my 05 LE 4-sp. automatic. I was getting 41 at the peak (summer 10) and I got 29 mpg on 12/27/11. I got in my accident 12/31/11. It had 155k.

A few days later I got a red 07 S with 70k on it, same 4-sp. auto and 1ZZFE. The engine seemed rougher. I got 29 mpg on my first tank, all city. I got 29mpg on my second tank, a mix of highway and city. The mechanic looked at it. He said the left front has a flat spot, which I will fix by getting new tires soon all around. He said no tune up was needed and the engine looks good (fuel injectors, intake, air filter, spark plugs--all mileage-robbing items). Battery had to be replaced, as it was at 40 percent life.

My question is this: Are the newer 9th gens built differently re: engine tolerances, which could affect economy? 06-08 vs. 03-05? The 05 seemed quieter (even accounting for the front tire's little flat spot) and got 31-32 on average in the winter (I got it with 85k and it went for 70k until the crash, when it was averaging 29-30). This 07 can't even hit 30k.

Also, is the gearing different on the S? If it is 4.10 vs. 3.08 it could account for the fuel slurp, but the revs look the same on both cars.

On both window stickers it says 30/38. I am disappointed in the S as it can't even reach the 30 mpg in city/highway mix and I may sell it in a few years.

The S has the side skirts and fog lamps, but I'd be assuming it's only 50-60 lbs. more than the LE/CE. I like the S because it has less miles, but it doesn't seem as solid as my 05 LE.

Also, it does not have the deluxe armrest, 6-disc changer and map pocket of the LE. I got it for $8,500 ($9,196 out the door after taxes) for 70k...no cheap deals on these Corollas.

[hardtopte72]

They are the same. The 05-08 have an updated piston to correct oil consumption vs. older 1ZZFE.

Your issue could be dirty throttle body, poor maintenance, cheap gas, or just a placebo affect. Get the tires fixed and do the real maintenance (trans drain and fill, throttle cleaning, intake gasket(it may be leaking causing a lean condition that hasn't been picked up yet), and good oil.

If the throttle was dirty when you replaced the battery it may have caused it to reset the ECU and that is why it feels rougher.

Also you had to have know the S didn't have those listed options. You must have researched and test drove the car.

[johnoh]

Originally Posted by jecht

The 05 seemed quieter

I assume you mean quieter as measured by the driver while driving, as opposed to when you have the hood open and are bent over the running engine. The second position is the way to compare engine noise, and the two engines should be about the same. The first position compares tires, wind noise, exhaust noise, etc. If tire noise is an issue, you may be paying for it in mpg.

Originally Posted by jecht

I am disappointed in the S as it can't even reach the 30 mpg in city/highway mix and I may sell it in a few years.

I hate my mpg every winter too. Wait until July and measure a tankful then, with full tires. You'll be happy again. Although the S does weigh more, and has more wind resistance, so you may lose a little there as compared to the 05, but not more than 0.5 to 1 mpg.

You got 29mpg on your final '05 tank and 29 on your first two '07 tanks. You probably need to do an all-highway tank before really being concerned.

[jecht]

Originally Posted by hardtopte72

They are the same. The 05-08 have an updated piston to correct oil consumption vs. older 1ZZFE.

Your issue could be dirty throttle body, poor maintenance, cheap gas, or just a placebo affect. Get the tires fixed and do the real maintenance (trans drain and fill, throttle cleaning, intake gasket(it may be leaking causing a lean condition that hasn't been picked up yet), and good oil.

If the throttle was dirty when you replaced the battery it may have caused it to reset the ECU and that is why it feels rougher.

Also you had to have know the S didn't have those listed options. You must have researched and test drove the car.

Thanks for the post!

What do you mean by placebo effect? I ran a 3rd tank and it was 29.5....they were all between 29.2 and 29.5 so far.

[jecht]

Originally Posted by johnoh

I assume you mean quieter as measured by the driver while driving, as opposed to when you have the hood open and are bent over the running engine. The second position is the way to compare engine noise, and the two engines should be about the same. The first position compares tires, wind noise, exhaust noise, etc. If tire noise is an issue, you may be paying for it in mpg.I hate my mpg every winter too. Wait until July and measure a tankful then, with full tires. You'll be happy again. Although the S does weigh more, and has more wind resistance, so you may lose a little there as compared to the 05, but not more than 0.5 to 1 mpg.

You got 29mpg on your final '05 tank and 29 on your first two '07 tanks. You probably need to do an all-highway tank before really being concerned.

Thanks! I have a question...I have this thread set up as automatic subscribe, but this post did not get forwarded to my email like the one above! It should do that on auto-subscribe.

[hardtopte72]

Auto subscribe is sometimes finicky.

As for placebo I meant on the rough feeling. When you got used to your old car you weren't looking for problems. When you got the new one you were more than likely looking closely for issues.

[jecht]

Originally Posted by hardtopte72

Auto subscribe is sometimes finicky.

As for placebo I meant on the rough feeling. When you got used to your old car you weren't looking for problems. When you got the new one you were more than likely looking closely for issues.

thank you! I am a new member, so forgive my ignorance. This forum is better than a lot of other forums out there for the 9th gen. It is informative and the members respond quickly and with intelligence!
take care,
josh

EDIT to add: I am new to this particular forum, although I posted once in a different forum run by the same hosting service back in '04 I think...then left...but discovered the 9th gen forum when I got my S.

[Camryv6xle]

tire pressure could cause less mpg, if plugs were replaced they may be gapped incorrectly which would def lead to poor mpg, intake may be dirty, vacuum lines may be leaking, weight affects mpg aswell alot of variables to contribute. who know maybe the s body kit is causeing drag instead of actually cutting through the wind better

[MD1032]

Tire pressure has way more of an effect than you think. I'm talking a few psi can cause a few % decrease in mileage...which is insane. When I first got my used car from the Subaru dealer I bought it from, I couldn't believe the mileage I was getting. High 30's...39 MPG one time. Then I found out that my tires designed to be set at 30 psi were actually set to 40 psi. I dropped the pressure down and my mileage immediately tanked and now runs ~36 MPG average. Of course, I would never reinflate them to 40 because I had so little grip on the road that I almost lost it a couple times even driving at conservative speeds in the rain. Point is, inflate your tires. They will lose air (no matter how much they cost) on a monthly basis at a minimum and must be reinflated. I drive a lot so I check mine once every two weeks. If your LE had the non-alloy wheels, the tire size on the "S" model with the alloy wheels is larger, so you will have worse mileage... but, heck, even different brands of tires of the same size can cause differences in MPG.

So basically, to really compare the two, you would have to have identical tires inflated to the same pressure and drive under the exact same weather conditions with the exact same traffic conditions.

I have been told that the panels on the "S" serve no other purpose than appearance and that the aerodynamics should be the same.

But all that aside, I would first investigate cleaning the throttle body and MAF sensor (that would cause major MPG problems if it's dirty) and replacing the original intake manifold gasket if it's still on there. Even if you bought a beautiful clean Carfax one-owner car, never underestimate the ability of that one owner to screw up the car or otherwise neglect it during the time they had it.

[hardtopte72]

Originally Posted by MD1032

Tire pressure has way more of an effect than you think. I'm talking a few psi can cause a few % decrease in mileage...which is insane. When I first got my used car from the Subaru dealer I bought it from, I couldn't believe the mileage I was getting. High 30's...39 MPG one time. Then I found out that my tires designed to be set at 30 psi were actually set to 40 psi. I dropped the pressure down and my mileage immediately tanked and now runs ~36 MPG average. Of course, I would never reinflate them to 40 because I had so little grip on the road that I almost lost it a couple times even driving at conservative speeds in the rain. Point is, inflate your tires. They will lose air (no matter how much they cost) on a monthly basis at a minimum and must be reinflated. I drive a lot so I check mine once every two weeks. If your LE had the non-alloy wheels, the tire size on the "S" model with the alloy wheels is larger, so you will have worse mileage... but, heck, even different brands of tires of the same size can cause differences in MPG.

So basically, to really compare the two, you would have to have identical tires inflated to the same pressure and drive under the exact same weather conditions with the exact same traffic conditions.

I have been told that the panels on the "S" serve no other purpose than appearance and that the aerodynamics should be the same.

But all that aside, I would first investigate cleaning the throttle body and MAF sensor (that would cause major MPG problems if it's dirty) and replacing the original intake manifold gasket if it's still on there. Even if you bought a beautiful clean Carfax one-owner car, never underestimate the ability of that one owner to screw up the car or otherwise neglect it durinTg the time they had it.

Actually the LE and the S both have the same tire size regardless of if they have alloy or steel wheels. It is 195/65/15. The CE is the one that has smaller tires. It has 185/65/15. I went from 185/65/15 to 195/65/15 and noticed no difference.

[jecht]

Originally Posted by hardtopte72

Actually the LE and the S both have the same tire size regardless of if they have alloy or steel wheels. It is 195/65/15. The CE is the one that has smaller tires. It has 185/65/15. I went from 185/65/15 to 195/65/15 and noticed no difference.

thank you!

I had the mechanic do a valve clean and fuel injector clean. Last tank I got was 34 mpg. 218.7 miles/6.363 gallons. But I ran 89 octane that time. I wonder if the 89 is that much better. I may run 89 then from now on if that's the case. usually, you can tell the halfway mark (I measure it at 7 gallons in a 13.2 gal. tank for clarity) two notches below the 1/2 tank gauge display. Hence, if you're at 210-30, 217-31, 224-32, 231-33 etc. etc. Just get a # and divide it by 7 when it goes 2 notches below and you'll know your FE.

I have the 195/65/15s set up at 30 psi as recommended by the manufacturer.

[hardtopte72]

Originally Posted by jecht

thank you!

I had the mechanic do a valve clean and fuel injector clean. Last tank I got was 34 mpg. 218.7 miles/6.363 gallons. But I ran 89 octane that time. I wonder if the 89 is that much better. I may run 89 then from now on if that's the case. usually, you can tell the halfway mark (I measure it at 7 gallons in a 13.2 gal. tank for clarity) two notches below the 1/2 tank gauge display. Hence, if you're at 210-30, 217-31, 224-32, 231-33 etc. etc. Just get a # and divide it by 7 when it goes 2 notches below and you'll know your FE.

I have the 195/65/15s set up at 30 psi as recommended by the manufacturer.

I run mine at 32-34 PSI cold. Not dangerous and a little bit better MPG.

89 Octane is a waste of money. That is a definite placebo affect.

Try and go back to 87 and see if you still notice a difference.

[MD1032]

Actually, 89 and 91 octane have a lower energy density than 87 and you will technically have lower mileage. If you get better mileage with 89, that could be bad. Does it ping a lot with 87? I think mine has pinged at high rpm's maybe once or twice, period, in the 10k I have driven thus far. These engines are designed to run on regular.

By the way, you can buy fuel injector cleaner at Wal-Mart and places like Auto Zone/Pep Boys. Simply add it to a full tank of gas and it will clean your fuel injectors and valves. Alternatively, buy a brand name kind of gas like BP or Shell that has fancier detergents, and that will also clean better than cheap gas.

[fishexpo101]

Depends on how they boost the octane rating - some use iso-octane, various butane, methanol, isopropanol, etc. to pump up the octane rating, generally varies from state to state, region to region. Some use more ethanol - ethanol which does have lower energy densities than regular gasoline, so in large enough amounts of it will more than likely result in net drop in fuel economy.

Higher octane ratings correlate to higher activation energies or amount of energy required to start a chemical reaction. For the most part, the majority of the fuel blends out there, the energy densities (energy per unit volume is the same) for the different octanes are amount the same.

Higher observed fuel economy with higher octanes than requires point to excessive engine pinging or detonating on the lower octane, which will cause the ECM to pull timing resulting in less fuel economy. Most likely due to heavy internal engine deposits. This is more common on cars with a considerable amount of mileage on them, as they are more likely to have these heavier deposits. Very common to see on older classic cars and high mileage commuter cars.

Varies from car to car - some see a marked increase in fuel economy, sometimes on the order of 10%-20% gain - depending on the cost per gallon of gas, you might actually save at the pump running higher octane. Others, see no change at all, and you just end up paying more at the pump.

In tank fuel injector cleans may help in cases where you see a bump in MPG after running a tank of higher octane gasoline. Stick with brands that have a large portion of polyetheramine (PEA) as part of their active chemistry. PEA was developed by Chevron in the 80's and is still considered one of the more effective gasoline additives still. Gumout with Regane complete fuel system cleaner, Chevron Techron Concentrate Plus complete fuel system cleaner, Redline SI-1 fuel complete system cleaner, and Valvoline complete fuel system cleaner (note the "complete fuel system cleaner" designation, as most of them also sell a less powerful fuel "injector" cleaner variant) - all have loads of PEA in them. I personally like Redline and Chevron - loads of PEA (~50%+), Valvoline and Gumout have quite a bit (~30-40%). With Gumout generally the best bang for the buck, as it goes on sale around here so often.

[hardtopte72]

This is why I said for him to attempt a switch back because he just had work performed. It's too early to decide that he has a marked increase caused by the octane.