Fingers

What is it's function on an fc? Could it contribute to a bad idle, running pig rich, and bad mpg?

eljefe62

ummm... to determine amount of oxygen in exhaust pulses... ie, too rich/too lean A/F mix
Yes, Yes, and Yes

Black13B

iTrader: (1)

the oxygen sensor is sorta like the engines "final product overview."

it determines what it just did, what the results were, and sends a signal on what should be changed in order to achieve better results.

so, yep.. affects alot of stuff..

Fingers

hmm... is it used only in closed-loop mode or does it monitor all the time?

jon88se

02 sensor is not used for WOT as I understand it

Fingers

what about idle? used for idle?

Aaron Cake

iTrader: (1)

The O2 sensor is NOT used for idle.

jon88se

we have the lovely lean/rich adjust to govern idle mixture hehe

Fingers

no we don't not s5 t2's anyway

Aaron, is it used for no load, but revving between 1000-2000?

RETed

O2 sensor is only used for high vacuum/low load cruising ranges.&nbsp It's only used for gas mileage at highway speeds.&nbsp It does not influence idle...unless you short the wires and blow the ECU.


-Ted

Bruce

A single wire o2 sensors only purpose is to test exhaust gas temperature. It is extremly inneficient thats why stand alone use a multi wire o2 sensor that tests cars that are running lean or rich.

Dan H

Multi wire 02 sensors....are they also known as wide band sensors? Or are they not the same?

Fingers

Right but i'm wondering whether or not it will affect my 1000-2000RPM in neutral misfire. Meaning the car randomly misfires if i depress the accelerator between 1000 and 2000 rpm

Would the o2 sensor be responsible?

MrFuzzy

iTrader: (1)

if you toasted the ECU it would kill the O2 sensor also? i fried my ECU and the O2 is an error code now.

Fingers

Anyone know?

HAILERS

What part of *the o2 sensor is not used at idle* is not understood? Idle being in this case, sitting still and not moving. Anyway, it's not messing your cars idle up or making it run pig rich. Look for bad plugs, bad timing, bad water thermo sensor, bad tps, bad timing, bad plug wires,.Bad compression on one or more sides of a rotor, compression varying by toooo much b/t front and rear rotor, air leak from acv (the anti-afterburn part of the acv), bad bad (bad, bad is the hard to find one).

This: **A single wire o2 sensors only purpose is to test exhaust gas temperature.***** is an incorrect statement. Read: http://www.flash.net/~lorint/lorin/fuel/lambda.htm

http://auto.howstuffworks.com/question257.htm

Fingers

does the gauge and the ecu share the same water thermo sensor?

And with regards to timing, i checked without the initial set coupler. Will there be a big difference if i check with the jumper in place?

Thing is, i'm getting no backfires. It just misfires at idle between 1000 and 2000RPM, and upon decelleration (not backfire... but small popping sounds as the rpm goes down, rpm is affected when popping is heard)

Thanks
-Ross

HAILERS

does the gauge and the ecu share the same water thermo sensor?

NO

And with regards to timing, i checked without the initial set coupler. Will
there be a big difference if i check with the jumper in place?

NO. As long as the idle speed is close to 750rpm when you set the timing. Anything around/over 1000 when setting the timing, the timing is messed with by the ECU progarm. So do it around 750rpm give or take. Just not over 1000rpm.

NZConvertible

No, wide-band sensors are completely different to the sensors used in cars. Multi-wire sensors have a heating element in them that brings the sensor up to temp quicker. O2 sensors don't give any useable readings until they're quite hot, so the sooner they can start working the sooner they can start reducing fuel consumption and emissions. Other than the heating element, multi-band O2 sensors work exactly the same as single-wire ones.

NZConvertible

No, the ECU thermosensor is on the back of the water pump housing under the alternator; the temp gauge sender is on the rear plate under the oil filter. If it doesn't do it under load I really wouldn't worry about it. How often do you need to rev your engine between 1000 and 2000rpm while sitting still? If it becomes a problem while driving then you should start troubleshooting.

NZConvertible

Completely wrong. O2 sensors do just that, sense the amount of oxygen in the exhaust gas. They have no way of measuring temperature. This is a very inaccurate statement. O2 sensors are installed into cars for one purpose, and that's to let the ECU maintain a stoichiometric A/F ratio while cruising to save gas. They are extremely good at measuring mixtures close to stoichiometric, so they do their job very well. The O2 sensors undeserved bad reputation comes from people hooking glorified voltmeters up to them and expecting to accurately read full-load mixtures. It was never designed for this and doesn't do it well. When you say multi-wire do you actually mean wide-band? If so then you're wrong again. Standalones can only use the same O2 sensors as factory ECU's use. Wide-band sensors require sophisticated temperature measurement and compensation solftware to work and AFAIK there is no aftermarket programmable EFI computer that has this ability. If you did mean multi-wire, then from my post above you'll see that these are no different to single-wire ones at reading mixtures, so you're still wrong.

Dan H

Oh ok, I see now. Thanks for the informative reply!