Crazy readings on A/F, Any ideas on this..

[BOBS90TURBO]

About a month ago my autometer A/F gauge started acting up, it has been fine since I installed it about a year ago.
It works like it should under throddle and when I let off the gas at highway speeds, but when I stop at an idle it starts going nuts, it just starts reading like it was open loop, and here is the crazy part, even my logger o2-r is reading from 0.13v to 0.74v at idle, it just bounces back and forth. It seems to be running good aside from bad gas mileage latley.

Could this be a bad o2 sensor, if so is there any advise on buying a high dollar o2 sensor.
Thanks Bob

 

[Omega]

And you worry about the pretty blinkey lights why?

 

[super95awd]

Ya, that's how it should act at idle. I don't get it .

 

[LandoAWD]

Ya, that's how it should act at idle. I don't get it .

I agree.

 

[trebornash]

Mine too! Are you saying your Autometer A/F gauge didn't
do it when you first installed it? I was told that it's normal
for A/F gauges to do that. Bought my gauge used tho.
Same symptoms

 

[Defiant]

The DSM O2 sensor is a cheap device. All it has to say is "okay" or "whoa" to the ECU. The fuel map in the ECU takes care of most of the details, but at certain points in the engine running conditions, it has to ask, "Does this make my ass look big?".... no, wait, that's some other question. It has to ask, "You getting enough gas through there to keep from incinerating the piston-tops?"

If you want to get real O2 readings, you need to get a real O2 sensor, and they cost real money. About $400 dollars compared to $60. And your ECU's too stupid to appreciate the gift.


http://www.wbo2.com/

 

[PaleDSM]

At idle the O2 sensor voltage is supposed to bounce back and forth as the ecu makes constand corrections to try and attaint a stoichiometric mixture. If it isn't boucing like that either your O2 sensor is shot or you are out of the adjustment range of the ecu which I think* is about +-20%

 

[Defiant]

You mean it really matters what kind of o2 you get?

Did ya... look at the link above?

 

[Omega]

But defient, my LM-1 uses a $60 sensor

 

[BOBS90TURBO]

The reason I thought my o2 was bad is my crappy autometer a/f gauge used to go down in the red(lean) and then turn off(lights go off)untill I hit the gas again, and then one day it started boucing back and forth to stoich/lean at idle.

At idle my o2-r goes from 0.09v to 0.76v at idle.

At highway(openloop) speed (2750rpm) it does the same,timing is around 33*

My FTO2's go back and forth from 103.1% to 124.2% at idle.

Does all this sound normal???? I just can't understand why my a/f gauge changed up the way it did, it seems my gas mileage went to shit when the readings changed. What happens when an o2 sensor goes bad??? Thanks

 

[dsm10sec]

Bob, my car goes from .03v-.86v ALL THE TIME and it's a brand new sensor, yours is fine. I get pretty damn good gas milage though.

 

[DSMJim]

I honestly wish they never sold those stupid air fuel meters. Guys buy them have no idea what they are supposed to do then think something is wrong with their car because of it.

Buddy, just rip that gauge outta your car and drive like normal and forget about it. Your car is fine that gauge is a piece of junk. If you want bouncy lights I'll sell you a disco ball you can hang from your mirror which will tell you just as much about the condition of your engine. Plus you wont have to explain to your friends what its for.

 

[ivanr4g63]

true... the a/f gauge is a POS compared to a real monitor system, yet, a bunch of people have it, so its best to use the best out of it since we cant take it back.
I decided to do some research, a nd put together this small article, hope it helps.

http://www.dsmtuners.com/forums/showthread.php?threadid=161136