Tip For *possibly* Better Gas Milage - Corolland: the Toyota Corolla Forums

Hello everyone!

I have an automatic '03 LE with 90,000 miles. I drive mostly highway miles to and from work during the day in Baltimore and get about 31 mpg on average, using the AC 50% of the time, and doing about 65 mph.

I took a trip to North Carolina last week. Before I left for the trip, I did something I had never done before. I cleaned the MAF sensor wires. Having never cleaned them before, I didn't know if I would see any noticable difference. My gas milage average increased to 38 mpg! I was doing everything that would usually hurt gas milage, and it still went up! I was driving in the mountains, so it was constantly going into 2nd gear and running > 3,000 rpm. Plus, 60% of my trip was on I-95 where I was doing 80-85 mph. And, I had my AC running non-stop. All things I was fearing would hurt my mpg. I attribute the gain to the MAF cleaning. Now that I'm back in Baltimore, my milage is still much higher than before the cleaning.

I run a K&N filter, which I know is a controversial subject in itself. Because of that, I really wanted to make sure the MAF sensor was clean. When I looked in, it was brown and cruddy as expected. I sprayed it down with the proper cleaner until shiny silver. When reading how to do this cleaning, I was told to expect slightly smoother acceleration, smoother idle, slightly better gas milage, and smoother shifting. All that came true for me... Obviously, different cars will experience different gains. But, if you've never cleaned a MAF sensor, it's worth looking into. You may be very happy with the results, as I was.

My wife has a 2001 CE. She has been complaining about bad milage lately. I'm anxious to clean her MAF sensor and see if she sees the same gains I did! I'll post the results of that test back to this post if anyone is interested.

Take care and I hope my post has helped someone out!

Mike

How to you clean MAF sensor in Corolla. Is it possible for a novice to do that?

Access-Denied (+1)

where is this sensor at? i got a 96 geo prizm.

MAF sensors are only on 2000+ Corollas. 7th gen Corollas (1993-1997) and early 8th gen Corollas (1998-1999) are MAP sensors - totally different situation (those do not respond this way to cleaning).

Cleaning is pretty easy - just make sure to get the wires on the inside.

Link to cleaning a MAF sensor on a MR-S - very similar to Corollas.

http://spydermagazine.com/2002/March/maf_clean/maf_clean.htm

How to you clean MAF sensor in Corolla. Is it possible for a novice to do that?

Totally! :-)

First, you need to buy a cleaner. The article I link to shows a different cleaner. But, personally, I went to Advance Auto Parts and bought "CRC Lectra-Motive Electric Parts Cleaner". A 20 oz spray can was $5. This stuff is good because it cleans, degreases, leaves no residue or oils, and won't hurt the plastic housing. CRC Lectra-Motive Cleaner. Worked perfectly for me.

Basically, I followed the steps on this Web Site for cleaning an MR2's MAF sensor. Orginally posted by fishexpo101 in the performance section of this site.

In addition, follow these steps... First, disconnect the battery. It will reset your radio stations, but it's a good thing to do when working with this stuff. I also cleaned the teardrop thing on the side (the thermostat) by spraying the cleaner on it. It should be an amber or brownish color - not black. Also, remember DO NOT TOUCH the thermostat or the wires inside the MAF sensor. These things are expensive and very fragile. And finally, when spraying the cleaner inside, don't spray it at full force. They're fragile and could break. Keep spraying and inspecting until the two wires inside are a shiny silver color like the pictures. I emptied almost a whole can on mine, that's how dirty it was. Let it dry totally and reinstall.

Hope that helps y'all out!

Mike

MAF sensors are only on 2000+ Corollas. 7th gen Corollas (1993-1997) and early 8th gen Corollas (1998-1999) are MAP sensors - totally different situation (those do not respond this way to cleaning).
Cleaning is pretty easy - just make sure to get the wires on the inside.
Link to cleaning a MAF sensor on a MR-S - very similar to Corollas.
http://spydermagazine.com/2002/March/maf_clean/maf_clean.htm

Fish, for a 98 corolla, is there anything to clean to improve mpg? Could you clean the MAP? And what does MAP stand for?

MAP - Manifold Absolute Pressure sensor. Generally cannot be cleaned or not respond at all to a cleaning (may potentially damage the sensor).

Not much you can do (no miracle sensor cleaning). Somethings to check to make sure they are in good shape: fuel injectors, air filter, sparkplugs, plug wires, good chassis ground (ground points), exhaust system, tires and wheels, tire pressure, O2 sensors, etc.

If you noticed that fuel economy has taken a big dive - might want to check those O2 sensors. They could be slowly going bad - sometimes called a "lazy" sensor and sometimes will not trip a CEL. Best way to check it to backprobe the sensor harness and look at the voltage levels. If you car has more than 100K miles - might be time for new sensors since they have a finite lifespan.

MAP - Manifold Absolute Pressure sensor. Generally cannot be cleaned or not respond at all to a cleaning (may potentially damage the sensor).
Not much you can do (no miracle sensor cleaning). Somethings to check to make sure they are in good shape: fuel injectors, air filter, sparkplugs, plug wires, good chassis ground (ground points), exhaust system, tires and wheels, tire pressure, O2 sensors, etc.
If you noticed that fuel economy has taken a big dive - might want to check those O2 sensors. They could be slowly going bad - sometimes called a "lazy" sensor and sometimes will not trip a CEL. Best way to check it to backprobe the sensor harness and look at the voltage levels. If you car has more than 100K miles - might be time for new sensors since they have a finite lifespan.

Where is the O2 sensor? Is it at the exhaust mani or the intake box?

Not much you can do (no miracle sensor cleaning). Somethings to check to make sure they are in good shape: fuel injectors, air filter, sparkplugs, plug wires, good chassis ground (ground points), exhaust system, tires and wheels, tire pressure, O2 sensors, etc.
If you noticed that fuel economy has taken a big dive - might want to check those O2 sensors. They could be slowly going bad - sometimes called a "lazy" sensor and sometimes will not trip a CEL. Best way to check it to backprobe the sensor harness and look at the voltage levels. If you car has more than 100K miles - might be time for new sensors since they have a finite lifespan.
Where is the O2 sensor? Is it at the exhaust mani or the intake box?

Exhaust. Always.

Fish: How do we check fuel injectors, ground points and exhaust?

The first time I did oil change with Mobil 1 I spilled some on the valve cover, some got on the spark plug wires and left a stain. Will this affect them?

(Ah, first time DIY oil change. I bought a funnel shortly afterwards.)

Where is it on the exhaust mani for the 8th gen corolla? Is it underneath the header cover? Will I have to take that off?

Yup, like Buurin mentioned - O2 sensors are always on the exhaust system. You have two O2 sensors - one usually on the exhaust manifold and one behind the catalytic converter (sometimes referred to upstream and downstream O2 sensors or B1-S1 (Bank 1, Sensor 1), B1-S2 (Bank 1, Sensor 2)). Usually the propblem sensor is the upstream one, the one before the cat. You should be able to see it by looking down at it from the firewall (may be hidden by the exhaust manifold heatshield).

Spilling a little oil won't hurt anything - for larger messes, cleaning it up as much as possible is a good thing (keeps engine cleaner, also prevents it from burning off). Not much you can do about the stain - oil penetrates the out covering pretty quickly, sometimes softening them. If you don't notice any nicks or cuts on the wires - you should be good to go.

Checking fuel injectors - sometimes you can use a a piece of metal (screwdriver) set it ontop of the injector and "listen" to the solenoid (makes a ticking, clicking noise). Only really way to check them is to remove them and have them flow tested.

Ground points are easy to spot - visual inspections are usually good enough (check for good clean connections, no frayed wiring, etc.) If you have access to a multimeter - you can check the resistances from point to point. NOTE: If you notice you lights dimming quite a bit and the battery is in good shape - could be a bad ground point somewhere. For older cars that exhibit these dimming headlamps with an extra electrical load (audio system, power windows/locks, etc.) - those grounding kits (heavy gauge wires that replace existing chassis grounds) - really do work.

Exhaust - also initially a visual inspection. Looks for physical damage, heavy corrosion, dents, cuts, and dark, sooty spots around joint and fittings (guaranteed sign of an exhaust leak). For other exhaust issues, like a slagged over or clogged catalytic converter (poor acceleration, huffing noise from exhaust, very poor fuel economy) - you would have to bypass the cat to check it (cut off, sometimes they back out the upstream O2 sensor and see how it runs).

Like always fish, very thorough

Can you clean the O2 sensor at the mani? Will that help the engine in any way?

I would NOT attempt to clean the O2 sensor. Usually, it will result in a dead sensor - I know I tried default_biggrin . But they can last a long time - if you notice that the car is getter very poor fuel economy - then it might be ready to change it and see what happens. Note - get OEM style Denso or similar O2 sensors. They run about $70 to $150 depending on where you shop. Be wary of "universal" sensors - run about $30 - they do not have a connector on the end, just bare wires, have to cannibalize the original sensor. Unless you really good a soldering connectors - not worth the hassle.

But check the easy stuff - like tire air pressure. I wouldn't start swapping parts until I exhausted other avenues first.

On my 2002 Corolla, 4-speed auto - I usually average between 32-34MPG on the highway - with a little city driving on the weekends. Running the A/C constantly and heavy traffic conditions will suck that down to around 28-30MPG.

G'day,

I am using a ram pod filter, everytime i clean and re-oil the foam filter element , it is routine for me to squirt electrical contact cleaner on the maf sensor and wipe it with a clean rag.

rey t

G'day,
I am using a ram pod filter, everytime i clean and re-oil the foam filter element , it is routine for me to squirt electrical contact cleaner on the maf sensor and wipe it with a clean rag.
rey t

Good idea Rey. Now that I've seen just how dirty those buggers can get, I'm going to clean my MAF sensor each time I do a filter charge (K&N) as well.

Thanks!

Mike

Bikeman982

MAF sensors are only on 2000+ Corollas. 7th gen Corollas (1993-1997) and early 8th gen Corollas (1998-1999) are MAP sensors - totally different situation (those do not respond this way to cleaning).
Cleaning is pretty easy - just make sure to get the wires on the inside.
Link to cleaning a MAF sensor on a MR-S - very similar to Corollas.
http://spydermagazine.com/2002/March/maf_clean/maf_clean.htm

What can people with 7th generation do to increase their gas mileage??

MAF sensors are only on 2000+ Corollas. 7th gen Corollas (1993-1997) and early 8th gen Corollas (1998-1999) are MAP sensors - totally different situation (those do not respond this way to cleaning).
Cleaning is pretty easy - just make sure to get the wires on the inside.
Link to cleaning a MAF sensor on a MR-S - very similar to Corollas.
http://spydermagazine.com/2002/March/maf_clean/maf_clean.htm
What can people with 7th generation do to increase their gas mileage??

I would say by using every old technique possible: oil changes like mad, tires fully inflated (i've ridden bicycle with low air and pumped it up, and man, was it easy to ride), an air intake (that's my belief though), slow accel, put in neutral when possible (ie. down hills, coming up on a red light), LIGHT LIGHT LIIIGHT cargo, clean your car and wax, when the dirt builds up on the surface of the car, the air flowing is no longer laminar flowing., if old fuel injectors get some fuel injector cleaning solution. If old engine, use oil treatment/additive - that makes the oil more viscous and whatever scratches or warps you have in the cylinder, it patches it up., tires aligned.

I have this ideology on my 1998 toyota corolla (the one with the f'd up trannsmission), and I get 38mpg with 192,000 miles on it. So... .............................good luck default_wink

Bikeman982

MAF sensors are only on 2000+ Corollas. 7th gen Corollas (1993-1997) and early 8th gen Corollas (1998-1999) are MAP sensors - totally different situation (those do not respond this way to cleaning).
Cleaning is pretty easy - just make sure to get the wires on the inside.
Link to cleaning a MAF sensor on a MR-S - very similar to Corollas.
http://spydermagazine.com/2002/March/maf_clean/maf_clean.htm
What can people with 7th generation do to increase their gas mileage??

I would say by using every old technique possible: oil changes like mad, tires fully inflated (i've ridden bicycle with low air and pumped it up, and man, was it easy to ride), an air intake (that's my belief though), slow accel, put in neutral when possible (ie. down hills, coming up on a red light), LIGHT LIGHT LIIIGHT cargo, clean your car and wax, when the dirt builds up on the surface of the car, the air flowing is no longer laminar flowing., if old fuel injectors get some fuel injector cleaning solution. If old engine, use oil treatment/additive - that makes the oil more viscous and whatever scratches or warps you have in the cylinder, it patches it up., tires aligned.

I have this ideology on my 1998 toyota corolla (the one with the f'd up trannsmission), and I get 38mpg with 192,000 miles on it. So... .............................good luck

Some very good tips which can be used by anyone on any car to help increase economy. Thirty-eight MPG is excellent. Maybe I should put more air in my tires and take all the extra stuff out of my trunk??

I don't have any hills back and forth to work but if I ever find one, I will shift to neutral and coast.

friendly_jacek

May I suggest slowing down?

When I started driving 75mph instead of 80mph, the mpg went from 30-31 to 33-36!

Bikeman982

May I suggest slowing down?When I started driving 75mph instead of 80mph, the mpg went from 30-31 to 33-36!

So if I just drive slower I can get better fuel efficiency??

What is the optimum speed?

I only drive fast when I am in a hurry (I always seem to be in a hurry).

May I suggest slowing down?
When I started driving 75mph instead of 80mph, the mpg went from 30-31 to 33-36!
So if I just drive slower I can get better fuel efficiency??

What is the optimum speed?
I only drive fast when I am in a hurry (I always seem to be in a hurry).

I dunno...I've gotten better fuel economy driving faster around 75-80 than 65-70. But that's in an 8th gen corolla. I've found out that I press on the accelerator a certain "x" amount to maintain speed at 60-65 as I would driving 75-80. But of course you can say, its not the gas your controlling, its the air. But...I dunno. O yea, try driving at night when cooler (not super cold). I drive like 100 miles every weekend one way to see my gf and I've gotten 400 miles to the tank before. But then again, in so.cali, there are minor hills that I just go neutral on. Well bike, what you might want to try since you don't have a bunch of hills, is when your approaching a stop light, put it in neutral, even if you slow down in traffic because letting your foot off the gas causes you to engine brake a little bit, and guess what, that uses gas too. The best fuel economy is going idle at 80mph!!! default_biggrin

Bikeman982

May I suggest slowing down?
When I started driving 75mph instead of 80mph, the mpg went from 30-31 to 33-36!
So if I just drive slower I can get better fuel efficiency??

What is the optimum speed?
I only drive fast when I am in a hurry (I always seem to be in a hurry).
I dunno...I've gotten better fuel economy driving faster around 75-80 than 65-70. But that's in an 8th gen corolla. I've found out that I press on the accelerator a certain "x" amount to maintain speed at 60-65 as I would driving 75-80. But of course you can say, its not the gas your controlling, its the air. But...I dunno. O yea, try driving at night when cooler (not super cold). I drive like 100 miles every weekend one way to see my gf and I've gotten 400 miles to the tank before. But then again, in so.cali, there are minor hills that I just go neutral on. Well bike, what you might want to try since you don't have a bunch of hills, is when your approaching a stop light, put it in neutral, even if you slow down in traffic because letting your foot off the gas causes you to engine brake a little bit, and guess what, that uses gas too. The best fuel economy is going idle at 80mph!!!

I am going to experiment with my speed and gas mileage.

Today I went 70 (well, 75 sometimes) back and forth to work. I am going to try doing it for a week and then see if I get more MPG that way. That would be two tankfulls of gas. If I don't - then back to 90.

Bikeman982

My gas mileage has improved from 28.5 to 33.0 MPG and the only change is the speed I drove.

When I got 28.5 MPG I was driving 80-85 MPH.

When I got 33.0 MPG I was driving 70-75 MPH.

There were no other significant differences and that is the sole basis for better fuel economy.