Fuel Economy 2001 Ce Auto 4 Speed - Toyota Corolla, Chevy Prizm (1998-2008)

Guest KnifeEdge_2K1

Hello all I'm new on the forum and I'd like to thank all of you in advance for your help and guidance.

Over the past few months I've been taking my sister's car (2001 Corolla CE 4-speed Canadian spec 136 000km on the odo or 80 000 miles) to school. Its a rather short trip about 3 kilometers but it beats walking in the winter and heat in the summer. The problem is after my first couple of fillups I started noticing how much gas the engine consumed, I did some research on the internet and found that the 2001 engine should use 7.8L/100KM while my average for 4 fillups has been 11.1L/100km, now I'm not an aggressive driver so I'm confused and unable to locate the problem. I've checked the air filter which is fine and added some fuel injector cleaner into the tank at my last fillup (I'm still using that tank of gas, btw the fuel injector cleaner i used is about 3 years old so it might have lost it's effectiveness, ill buy a new bottle for my next tank of gas)

The only other fault that I can think of that would cause this kind of decrease in economy (using 43% more fuel) is a faulty oxygen sensor, faulty injectors, or faulty sparkplugs/wires. All of which I cant check ( i cant get under that black plastic thing that covers the plugs and wires, i dont want to remove it since i dont know what's under it. I know that in winter the fuel economy is expected to decrease but 43% is a bit too much, my friend who has a 2003 avalon only experienced a 15% drop from his rated fuel economy from 11.1 rated to 13.4 L/100km.

Please advise, I'm the one paying for fuel and it's getting to be a real pain since i have to save as much as i can for university.

P.S. sometimes when i stop and idle the engine makes a loud vibrating sound which goes away when i shift into neutral or start moving again, this doesnt happen very often and I think its due to bad engine mounts

P.S.2 I've read the review on the corolland site for my model corolla and it says that the interior noise is relatively quiet, in my car under even mild acceleration the engine seems quite loud, i do not have a tachometer on the car so i cant tell what the engine speed is, id estimate it at about 2500-3000 rpm when it shifts up

I've got a 2001 LE 4-speed auto - on my last tank I got 34.06 mpg, all city driving.

The only suggestion I can offer is to check the air pressure in the tires, I increased mine from 30 to 34/35 and it helped with the mileage.

My car has been very good at gas mileage, I rarely get below 30 mpg in the city.

Guest KnifeEdge_2K1

im still on my snowtires and they're all 30 psi cold/warm (i checked last week after i drove like 4 kms, do tires heat up that fast?)

(i checked last week after i drove like 4 kms, do tires heat up that fast?)

Yes. 4 km is enough to increase pressure 1-2 psi. Cold pressure really does mean cold (no driving, no direct sunlight).

Guest KnifeEdge_2K1

any other sudgustions?

anyone know how to open up that plastic piece of crap that covers the spark plugs wires ?

or anything to do with the wierd vibrations im getting?

Ti-Jean

"Its a rather short trip about 3 kilometers..."

Here lies the reason.

1) Trips are very short and your engine is in warm-up mode all the time plus frozen drivetrain, transmission, bearings, etc.

2) Cold canadian winter temperatures and winter tires.

3) Winter gas

I would hardly compare that with what Kathy or others might experience with longer distance city driving somewhere in the sun belt.

Before I would have the car looked at by a mechanic, now that the temperature is warmer and winter behind us, when you install your 3 season tires back on (if not already done), take a smooth long (several hundred kilometers) drive and check back your mileage.

I bet, you'll be back in the 7l/100 km range, maybe less for a tankful of highway driving.

Just imagine, you start your engine cold every 3 km. Over a 300 km tank, that's 100, yes, 100 cold starts over a period of a month.

Guy next door brags about how is Corolla is thrifty on gas. He drives 300 km straight down the road on a mild traffic free sunday morning. Comes back the same day. 600 km total, no more than 2 cold engine starts. Car gets 6.0l/100km instead of 11.

Guest KnifeEdge_2K1

yeah i guess ur right, techincally its 200 cold starts, today we're getting our last dose of snow fall, hopefully mileage increases, thanks for the help guys

on a final note, does anyone else on this forum live in canada (ontario to be exact) and own a corolla? id like to compare our fuel econ stats

I live in Quebec but I drive mostly highway (over 90%) as I take the bus to work. Anyway, I get about 6l / 100 km in the summer and about 7 to 7.5 in the winter. I use winter tires with pretty soft rubber.

My experience is that one of the most important factors is how fast I drive. Checking tire pressure in the winter is also crucial otherwise your fuel economy will dip with the temperature (you loose about 1 psi for every 5 °C). Make sure you don't check it in the sun or only on warm days.

Guest KnifeEdge_2K1

i was wondering, why is it that the engine must reach operating tempreature before you get the best fuel economy ... why is there an operating tempreature at all? is it because the engine oil viscosity?

Engine must reach operating temps to get the best efficiency - all boils down to emissions and drivability. Engine must be at certain temperature - so that certain engine variables are eliminated. This would include items like stable coolant temp and warmed up engine oil. Switching over to a thinner oil will not help much - just be easier to start - once it get hot enough, a thicker oil is preferred.

Short distance driving will really kill fuel economy. For the distance you mentioned - the car is barly out of open loop mode. During warm up, full throttle and in the event of a failed sensor - that the system is running in open loop mode (not using all sensors to optimize fuel calculations). This mode - it ignores feedback sensors like the O2 - just looks at throttle postion, engine speed, and temperature.

The plastic engine cover is held on with two 10mm nuts on the front and two plastic-fluted clips on the back. To pull the plastic clips out - grab the flatted edges on the top with some pliers (needle nose works perfectly) and pull straight up with a slight turn. Becareful - those are real easy to break off - not a deal breaker since the cover is only cosmetic in function.

If you drive those short distances - be a good idea to "clear" out the engine with a longer trip every once in a while (weekend?)- might even help with the fuel economy.

Guest hanijamal

yeah.. thats rough.. thats really poor milage even for winter.. during winter.. im up to 9.3 ish but 11 is an awful lot..check tire pressure.. if thats ok..then take it in to Toyota.. get a full check up done...i get about 500Km's on a full tank during winter and about 600 during the rest of the year

Guest KnifeEdge_2K1

that's what i said, the pressure is fine, like 29-30 psi cold

i dont know if they charge money for a check up, i know a tune up will cost money tho

To get the black plastic piece off the top of the motor you need and set of wrenchs or a socket set will do. Either is fine. Preferibly the socket set. There should be four screws holding on that piece. Remove the oil cap out of the way because it might catch when you lift up the cover. Thats it just four screws. To get to the spark plugs, after you take off the plastic piece you will see the four cylinder areas. Take off the the cover to the spark plug wires and to remove the wires you need to remove the bolt holding it in to place. They are not spark plug wires but I can not remember the name of them. To remove the spark plug you will need a 6 inch extension and the spark plug socket. Hope this helps.

Dai_Shan

Although it says 30psi on the door frame...30psi is considered very low among most people i know...and people here.

Higher the PSI the better the gas mileage. Most people i know drive there tires at 34-36. Keep in mind that these tires are usually rated for up to 42-45PSI.

tire pressure doesn't sound the issue here tho (as you seem to know)

gLuck man

I am facing even worse situation: about 11.5L/100km! In January, I got even 12.5!!

I think my driving schedule is the reason. Every day, I go to 2.4km distance and return after about 15 minutes. And I do it 4 or 5 times a day, from before sunrise to until about 8pm. My tire pressure is 33-34psi. The average winter temperature in this part of Ontario is less than -15C in January.

-- Is it OK to get 11.5L/100km in such situation?

-- Is my driving habit doing damages to the engine? What kind of 'extra' maintenance do I need (like more frequent oil change)?

My car is Corolla 96/1.6L/Auto.

Thanks.

Ti-Jean

1-- Is it OK to get 11.5L/100km in such situation?
2-- Is my driving habit doing damages to the engine? What kind of 'extra' maintenance do I need (like more frequent oil change)?

1- Yes, unfortunately. As we said, short distance driving kills fuel economy, especially in the winter. If you have an engine block heater and can use it, it would be a great help for your conditions. You'll more than save on gas what it would cost in electricity bills.

2- In a case like this, I would say change your oil after no more than 3-4 months, no matter the mileage, as you may have only a couple K Km on your oil. Don't go heavier than 5W-30. Take the car on the highway for a 20-30 minute ride from time to time to clear the moisture and condensation that is present in the oil of a frequent short distance car.