gas milage

[phipps192]

realy gettting low milage on my corolla 100 wagon, any idea of the cause?

[Kiwi-Corolla]

Welcome to the forums. How many miles has your engine travelled? Start by checking how clean your air filter is and how inflated your tires are. Also try changing the spark plugs, spark plug wires, rotor, oil and filter. Have a look at the temperature gauge next time you're driving the car, it should sit on half or just under. If it's lower than that then there's a chance that your thermostat needs replacing, which can play a big role when it comes to fuel consumption.

There are a lot of other factors which could contribute to the poor fuel mileage, such as dirty or leaking injectors, vacuum leaks, exhaust leaks, sticking EGR valve, incorrect timing, malfunctioning oxygen sensor, worn valve guides, bad fuel pressure regulator or fuel filter, clogged PCV valve etc etc. Start by checking the simple things first and go from there

[phipps192]

same feeling i been getting about some of the stuff u mentioned, however i dont know where my oxygen sensor is located but that shoulnt be hard to find, hopefully!!!

[Corollajoe]

oxygen sensor is bolted into the front of your exhaust manifold

[phipps192]

the thing is mine is there its just that i dont know where the plug is for it

[Kiwi-Corolla]

Originally Posted by phipps192

same feeling i been getting about some of the stuff u mentioned, however i dont know where my oxygen sensor is located but that shoulnt be hard to find, hopefully!!!

Fortunately the oxygen sensor is very easy to find. As mentioned above, it's located in your exhaust manifold. Depending on the year of your wagon, it could be on the side or even part of the down-pipe. It'll be easier to see it by removing the heat shields. You can test the oxygen simply by using a digital multimeter. If you have one of these then let me know and I'll tell you how to test it

Originally Posted by phipps192

the thing is mine is there its just that i dont know where the plug is for it

The wiring for the plug should lead past the distributor. If there's no wiring/plug on the end of the sensor then someone has probably cut it off, hence the poor fuel mileage.

[phipps192]

i have a multimeter, but what exactly is the function of the oxygen sensor anyways and its significance

[Kiwi-Corolla]

Originally Posted by phipps192

i have a multimeter, but what exactly is the function of the oxygen sensor anyways and its significance

The oxygen sensor measures the amount of oxygen in the exhaust gas. The ECU will adjust the mixture either richer or leaner based on the signal from the sensor. When the oxygen sensor fails, the ECU starts guessing what the air/fuel ratio should be, so you use a lot more fuel than you should

EDIT: Typically when the oxygen sensor fails, your check engine light will come on. However, if the condition of the oxygen sensor is gradually getting worse and worse but it still hasn't failed completely, then the check engine light won't come on. This is why it pays to check it with a digital multimeter.

[phipps192]

no wonder mine as been blinking, so this really affect fuel consumpion rate

[Kiwi-Corolla]

Originally Posted by phipps192

no wonder mine as been blinking, so this really affect fuel consumpion rate

Yep, it plays a huge role in terms of the fuel consumption. The first thing you should do is make sure that the check engine light isn't giving you any codes in addition to the oxygen sensor code. Since you said yours is an AE100, it should be ODB-I. Look in the engine bay and you'll see a small black box next to the left hand side strut tower that says 'Diagnosis' on it. Get a paper-clip or a small piece of wire and put one end into the port labelled TE1 and the other end into the port labelled E1 (the labels are found on the underside of the diagnosis box cover, much like a fuse-box).

Turn the key to the 'ON' position, but don't start the engine. If your connections are correct then the check engine light should start flashing. Keep note of how many times it flashes as this is the code it is giving you. For example, if the code was 35 it would flash 3-times, have a short pause, then flash 5 more times, then have a long pause. If it repeats the same code after the long pause then that means it's the only fault detected, but if it flashes for a different period of time then that means there is more than one fault. If it flashes continuously with no pauses in between then that means there is no fault detected at all.

Once you have the code, post it here and I'll tell you what it means . For reference, the code for a faulty oxygen sensor is 21 (shown as two 0.5 second flashes, a 1.5 second pause, and one 0.5 second flash).

[phipps192]

thanks a lot, check it first thing tomorow an let u know wats really happen, bless up