Last year I bought a 98 Corolla VE from the original owner, it has 117,500 miles on it. I have known them for 4 years. The car had been wrecked in the right front corner. I gave their insurance company $500 for the car, and put $538 in it to put it back together.
It runs and drives GREAT. But after running my first tank of gas, I was surprised that I only got 27 mpg, both in town and highway, but more highway miles.
When I had it apart, I did replace the air filter, and checked the air pressure in the tires.
Am I expecting too much? Or should it be getting better gas mileage? Maybe throw in a set of new plugs? What else?
With this second tank of gas, I ran some Seafoam thru the pcv to clean it out, it seems to run smoother. I put the rest of the bottle in the gas tank to clean the injectors.
Go to Toyota and get Iridium plugs, should last about 100K miles, change the oil to synthetic just get the cheap stuff "its still better than pure dyno",
also go get a Reusable K&N filter or TRD "but it cost more" and drill some door knob size holes on the lower airbox and take out the hose...
and ask your Toyota dealer for their fuel system cleaner
It should run better and get a better fuel economy...
AND YEAH... THE Mass Air Flow sensor MUST BE GUNKY.
To clean, you will need:
Philips screw driver "should be right sized"
MAF sensor cleaner
"can be bought at any autoparts store, if not available just get the Electronic contact cleaner"
AND A BRAIN! LOL!
1.Find the MAF sensor
2.It Should be on top of the airbox or intake hose "it always has toyota embossed on it"
3.Unclip and pull the harness "spray clean the contact too" and undo the screws on the sensor.
4.Pull it out gently and check if theres dirt "even thin oil can affect fuel eco bad"
5.Spray the sensor clean, it looks like the "uvula" and and if you look up on it there should be the temperature sensor"s" clean it too, let it dry... and check if its clean, if not redo number five, until clean and dry...*
6.Replace MAF sensor, screws and sensor harness.
7.Start engine and take it for a test drive "make sure to floor it." 2*
*:member not responsible for wrong procedure on MAF cleaning, wrong procedure should be repaired at auto owners cost.
2*:member not responsible for speeding tickets and or accidents.
An oxygen sensor must be tested with a digital voltmeter. If an analog meter is used for this purpose, the sensor may be damaged.
Testing O2 sensors that are installed
The engine must first be fully warm. If you have a defective thermostat, this test may not be possible due to a minimum temperature required for closed loop operation. Attach the positive lead of a high impedence DC voltmeter to the Oxygen sensor output wire. This wire should remain attached to the computer. You will have to back probe the connection or use a jumper wire to get access. The negative lead should be attached to a good clean ground on the engine block or accessory bracket. Cheap voltmeters will not give accurate results because they load down the circuit and absorb the voltage that they are attempting to measure. A acceptable value is 1,000,000 ohms/volt or more on the DC voltage. Most (if not all) digital voltmeters meet this need. Few (if any) non-powered analog (needle style) voltmeters do. Check the specs for your meter to find out. Set your meter to look for 1 volt DC. Many late model cars use a heated O2 sensor. These have either two or three wires instead of one. Heated sensors will have 12 volts on one lead, ground on the other, and the sensor signal on the third. If you have two or three wires, use a 15 or higher volt scale on the meter until you know which is the sensor output wire. When you turn the key on, do not start the engine. You should see a change in voltage on the meter in most late model cars. If not, check your connections. Next, check your leads to make sure you won't wrap up any wires in the belts, etc. then start the engine. You should run the engine above 2000 rpm for two minutes to warm the O2 sensor and try to get into closed loop. Closed loop operation is indicated by the sensor showing several cross counts per second. It may help to rev the engine between idle and about 3000 rpm several times. The computer recognizes the sensor as hot and active once there are several cross counts. You are looking for voltage to go above and below 0.45 volts. If you see less than 0.2 and more than 0.7 volts and the value changes rapidly, you are through, your sensor is good. If not, is it steady high (> 0.45) near 0.45 or steady low (< 0.45). If the voltage is near the middle, you may not be hot yet. Run the engine above 2000 rpm again. If the reading is steady low, add richness by partially closing the choke or adding some propane through the air intake. Be very careful if you work with any extra gasoline, you can easily be burned or have an explosion. If the voltage now rises above 0.7 to 0.9, and you can change it at will by changing the extra fuel, the O2 sensor is usually good. If the voltage is steady high, create a vacuum leak. Try pulling the PCV valve out of it's hose and letting air enter. You can also use the power brake vacuum supply hose. If this drives the voltage to 0.2 to 0.3 or less and you can control it at will by opening and closing the vacuum leak, the sensor is usually good. If you are not able to make a change either way, stop the engine, unhook the sensor wire from the computer harness, and reattach your voltmeter to the sensor output wire. Repeat the rich and lean steps. If you can't get the sensor voltage to change, and you have a good sensor and ground connection, try heating it once more. Repeat the rich and lean steps. If still no voltage or fixed voltage, you have a bad sensor. If you are not getting a voltage and the car has been running rich lately, the sensor may be carbon fouled. It is sometimes possible to clean a sensor in the car. Do this by unplugging the sensor harness, warming up the engine, and creating a lean condition at about 2000 rpm for 1 or 2 minutes. Create a big enough vacuum leak so that the engine begins to slow down. The extra heat will clean it off if possible. If not, it was dead anyway, no loss. In either case, fix the cause of the rich mixture and retest. If you don't, the new sensor will fail.
Testing O2 sensors on the workbench.
Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.
(*instructions for an MR2*)
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89 Corolla All-Trac Sedan White 188,xxx (Sold)
89 Corolla All-Trac Wagon Blue 172,xxx (Current)
On long runs I get 32. Stop and go 27. I have 169000 miles on a 94. The manuals and 4 spd automatics have an overdrive. When my mileage fell off I changed the spark plug wires. These cars eat the spark wires up due to the heat. I had the same problem with 91 Capri. Get wires with a lifetime guarantee.
On long runs I get 32. Stop and go 27. I have 169000 miles on a 94. The manuals and 4 spd automatics have an overdrive. When my mileage fell off I changed the spark plug wires. These cars eat the spark wires up due to the heat. I had the same problem with 91 Capri. Get wires with a lifetime guarantee.
Is the 32/27 before or after the wires?
I can manage 38mpg on the highway and summer gas @ 60-65mph. Go any faster, Im looking for a 6th gear
That 38 is with a manual transmission, I assume. While yours has overdrive, the original poster is suffering from a 3-speed automatic without it. It would be expected that their gas mileage would be worse, especially at speeds above 65 mph (if I recall correctly, the 3-speed does close to 4,000 revs at 75 mph, while my 4-speed does around 2600. I'd expect the difference in mileage between the two to get bigger the faster you go.)
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