testing o2 with scan tool

[Quadsportz]

My 97 eclipse gst is running lean. I have a scan tool/ obd2 reader. How would I check my front o2 sensor with it to see its working properly. I have stock ecu,Injectors,stock boost psi. 21hg of vacuum at idle and no boost leaks.

 

[delta448]

How do you know it's going lean and not rich? Usually when the sensor dies, you run rich.

Are you getting misfires? Misfires are seen by any oxygen sensor as running lean. No matter how much unburnt fuel gets into the exhaust, the sensor still only cares about the extra unburnt oxygen that would accompany a misfire. Extra oxygen in the exhaust = lean value sent from sensor.

If your scan tool allows you to view live data, find the front O2 sensor and watch to see if it cycles between 0.2 and 0.8 volts. However, if the sensor is good and you really are running lean it's going to be hanging out at low volts anyway, which is also where it will be if it's dead. You can do the same thing with a voltmeter across the signal leads of the sensor, if the voltmeter is quick enough to follow it's cycling.

 

[ICM_MikeLago]

O2 sensor wiring, testing, operation, changing, bypassing

 

[Quadsportz]

I know its running lean because the plugs are gray ish white and there's white build up in exhaust manifold. So your saying a bad spark plug wire that's causing misfired will make it run lean?

I have no codes for misfire. The car has a lil stumble for a second like every 15 sec at a idle. Also stumbles between 1800-2200 Rpm it makes the car shake and buck a little.

 

[delta448]

So your saying a bad spark plug wire that's causing misfired will make it run lean?

No, it won't actually run lean, the ECU will just think it is and will adjust fuel trims to add fuel.

A grayish white plug and white exhaust can mean different things. Depending on how white, the car may actually be very well tuned. It can also mean you're burning oil or coolant though. Know anyone with a wideband?

 

[Quadsportz]

No I don't know anyone with a wideband. I was concerned about the white carbon build up inside the exhaust manifold and turbo o2 housing. Also the turbo hot side propeller is white. My coolant level does not go down any and I don't smell antifreeze out the exhaust

 

[delta448]

You may indeed be a little on the lean side, but without a picture we can't say for sure. Maybe you can compare it to the pictures in this thread:
http://www.dsmtuners.com/forums/newbie-forum/348674-took-my-exhaust-housing-off-found-my-turbine-wheel-white.html

 

[DSMnoobsause]

you need to go in and watch the O2 sensor voltage when its fully warmed up. should cycle between .20-.80v if it goes lower then .20 and higher then .80 it will need to be replaced. that is if you have no exhaust leaks or vac leaks.

http://www.gnttype.org/techarea/ecmsensors/O2sensors.html

 

[Quadsportz]

Ok I drove my car around got it fully warm. On the scan tool the lowest reading I got was .1 the highest was .720