What is the MAF Sensor and what does it do??? What is the O2 Sensor and What Does it do??

More Importantly How do you tell if your MAF is Dead??
How Do you tell if the O2 Sensor is Dead???

I was going to answer but I seen tfv630 in this thread and thought theres no point, you will get the best possible answer.

P.s Search ^^ Button is your friend.

http://auto.howstuffworks.com/fuel-injection4.htm

sorry was being lazy

Maf usually use a "hotwire" to measure flow. essentially alls it does it is try and remain at an equal temp by increasing and decreasing voltage depending on the airflow.
the more flow the more volts required to keep the wire hot.

As for o2 sensor it measures the amount of o2 in your exhaust giving the best possible mixture in closed loop.

I did a Search and Came up with very little..
It still does not tell me how I know if one of them is Dead???


So I can assume if my 02 Sensor is Dead the car is gonna run Rich ?? ( Which Seems to be happening)
But not the MAF ??

some other cars use a "flapper or vein "type airflow meter not 100% sure on there internal workings though

I did a Search and Came up with very little..
It still does not tell me how I know if one of them is Dead???


So I can assume if my 02 Sensor is Dead the car is gonna run Rich ?? ( Which Seems to be happening)
But not the MAF ??


Normally if your o2 is dead then your ecu light would be on, ditto for the maf.

There is a simple test to see if your MAF is working,

Start your car let it idle for a min then disconnect the plug from the MAF. if its dead then there will be no change in the way your car runs, If it coughs splutters or the revs fluctuate then its still working to some extent. Thats just a simple test to try at home.

What makes you think one of them is dead??

So if the MAF was dead the car would not run ??

EDIT.. I just checked my Spark plugs and they are Black and they have done only 5000k's

It will run but not very well, generally the car will be "laggy" and not responsive at all.

Maf Works It started to Idle Badly then Reconnected it and it was fine..


So that leaves the Oxygen Sensor so where would that be on a TE 6g72?

have a look under the car were the front and rear pipes meet. Its the sensor with the wires coming out of there. Tried to see it on mine but its too low, can only see the wire leading to that area.

have a look under the car were the front and rear pipes meet. Its the sensor with the wires coming out of there. Tried to see it on mine but its too low, can only see the wire leading to that area.


It's covered by the heat shield isnt it

The o2 should poke out through the heat shield

Yeah it all looks connected but I have no way of testing.. I will leave that till the weekend and spend some time under there..

The o2 should poke out through the heat shield

Yep.


Magnat, dont get me wrong but if there was a problem with one of the sensors an error message would come up in the electric system.

CODE 11: Oygen sensor circuit
CODE 12: Air flow sensor
CODE 31: Knock sensor circuit
CODE 41: Fuel Injectors
CODE 13: Intake air temp sensor

etc

OXYGEN SENSOR
TO TEST.

Run engine until reaches normal operating temp
Backprobe the oxygen sensor wiring connector and measure the voltage while engine is running at 2.500RPM
The voltage should fluctuate between approx. 0.1 & 0.8 volts at least seven times over a 10 second period, indicating its fine.

there not to expensive to replace

Yep.


Magnat, dont get me wrong but if there was a problem with one of the sensors an error message would come up in the electric system.

CODE 11: Oygen sensor circuit
CODE 12: Air flow sensor
CODE 31: Knock sensor circuit
CODE 41: Fuel Injectors
CODE 13: Intake air temp sensor

etc

OXYGEN SENSOR
TO TEST.

Run engine until reaches normal operating temp
Backprobe the oxygen sensor wiring connector and measure the voltage while engine is running at 2.500RPM
The voltage should fluctuate between approx. 0.1 & 0.8 volts at least seven times over a 10 second period, indicating its fine.

there not to expensive to replace


Nice work ;) :thumbsup:

Generally isn't the test; Bad fuel economy = Quite possibly dead O2 sensor

I found this to be the problem in my skyline. Once the O2 was changed there was a huge difference in economy.

Generally isn't the test; Bad fuel economy = Quite possibly dead O2 sensor

I found this to be the problem in my skyline. Once the O2 was changed there was a huge difference in economy.


Its not always the o2 that causes a car to get bad fuel economy thats why there is more accurate testing procedures. Dirty injectors can also cause loss in economy so to can dud pressure reg or several other contributing factors.

Sorry magnat not intending to change your topic here...

Just quickly;
How often should things such as O2 sensors be changed or injectors cleaned to maintain the economy of a car???

Sorry magnat not intending to change your topic here...

Just quickly;
How often should things such as O2 sensors be changed or injectors cleaned to maintain the economy of a car???


IMO its best to have the injectors ultra sonically cleaned every 75,000k's and use an intank cleaner in the "between" time.

As for the o2 sensor only needs replacing when it's faulty.

Well Bad Ecomony is definately happening, Running Rich is also happening and I tested the Maf and it works so I am left with the 02 Sesnor.. I will see about it tommorrow when I get a Chance..

Like tfv630 said, it could be a number of things causing bad fuel economy. But I would imagine the O2 would probably be the cheapest part to start somewhere with. I used a EL falcon O2 sensor for the skyline (fits right in), cost $70 from repco. So I can't imagine a magna one being too expensive.

Let us know how you go if you do change it. :)

Just as a point of interest magnat how many k's has youre car done and how regularly do you service it, and have you had youre injectors cleaned. It could be as simple as that, even if it is youre o2 sensor it would def be worth you having the injectors done.

Always Service it at home..
All that stuff I cannot do is done by my Mechanic Every 50.000K's

So the Oil Change is done every 5000 with New Oil Filter, Fuel filter only just been done and is all good..
The Injectors should be OK as I ran some Boost and Clean about a month ago..

Always Service it at home..
All that stuff I cannot do is done by my Mechanic Every 50.000K's

So the Oil Change is done every 5000 with New Oil Filter, Fuel filter only just been done and is all good..
The Injectors should be OK as I ran some Boost and Clean about a month ago..



That stuff does very little to actually clean the injectors properly, i always thought it worked until i had my injectors done professionally. he showed me the before and after of the spray patterns. also the flow test and the leak down test. Needless to say since then i know the stuff in the bottles doesnt really work that well, and my car used alot less fuel after and ran alot smoother