bobbyd

iTrader: (10)

what should be the normal readings on a o2 sensor?

i have a Aeroforce interceptor gauge and i was scanning both of my o2 sensors bank1 & bank2.

bank 2 (passenger side) i got readings of 445mv.

bank 1 (drivers side) i was getting readings all over the place anywhere from 75-8XX. it would jump from like 75 to 380 then to 775 then 452, etc just all over the place.

i replaced my passenger one yesterday with a denso. my drivers side one was replaced no more than 2 months ago with a corvette bosch one.

is that normal readings for the bosch? am i running lean / rich?

eseibel67

iTrader: (10)

How are you checking them? First of all, engine needs to be warm. Second, RPM should be revved up to about 2500 to get a nice exhaust stream over the sensors.

Voltage should constantly fluctuate between .125v and .875v. This up and down should happen a few times every second.

Average should be about .450v.

waterbug1999

iTrader: (3)

Yea, how are you reading it?

Bottom of the pic, thats the voltage and how it reads it... it will look different when its cold and when its under WOT. But, this is what its suppose to look like. You can see the wideband 02 in purple on the top switching like that too.






And here is what it does when it doesnt get a connection... You can see one is switching like its suppose to and the other one (in blue) isnt.

bobbyd

iTrader: (10)

i was reading it with the aeroforce interceptor gauge.

i think i found the problem.

basicly the interceptor has 3 o2 sensor settings.
sb1 sb2 and sb3.
i had it on sb1 (which im assuming is bank1 and sb2 which is the one that was staying constant at 445. so what i did was try to run sb3 setting and it started to scan and jump from 100-8xx. same thing that sb1 was doing. so im guessing sb2 wasnt reading anything which was the reason for it to be solid at 445.

haven't got any codes since last night once i change the passenger o2.

hopefully it wont give me the running lean code anymore po174. i sprayed some carb cleaner on the hoses that go to the intake and on the air plates and on the egr plug and none cause my idle to raise so i dont have any vacuum leaks.

i change my plugs just gotta do #8 tomorrow and see if that was causing my other problem where the car felt slow at about 50-60mph.

waterbug1999

iTrader: (3)

Not familiar with this interceptor gauge, but why you want to look at 02 voltage for? Is it just to make sure they are switching and not lazy or dead?

What other problem?

bobbyd

iTrader: (10)

i wanted to check them because i had been getting bad gas mileage and sometimes on idle it wouldnt idle good for a few minutes.
so wanted to make sure it wasnt lazy and that they were swhitching right etc,

besides the idle and bad mileage when im cruising and i get to about 50-60mph the car falls like a dog till about 65+. i know that this is more than likely do to the plugs though,

waterbug1999

iTrader: (3)

gotcha...

bobbyd

iTrader: (10)

tomorrow i just gotta change the last spark plug #8 and hopefully that fixes my problem.

waterbug1999

iTrader: (3)

i dont think one plug will fix the issue.. You need a wideband in the car so you can see your AF..

eseibel67

iTrader: (10)

Downstream sensors are not supposed to fluctuate as much. They should be closer to .450V most of the time which tells the PCM that the cat is doing it's job.

My guess is your "sb2" is a downstream sensor reading.

waterbug1999

iTrader: (3)

i guess I was assuming he had no cats, good point.

doublea87

iTrader: (16)

if your having lag issues on acceleration around 60 mph and a poor idle quality you might want to check your wires and coils. a poor coil resistance will cause similar conditions.

bobbyd

iTrader: (10)

you are correct. I don't have any cats.

bobbyd

iTrader: (10)

i will check this.

i was thinking of changing out hte wires aswell since I did the plugs.

im gonna have to check for vaccum leak where the intake gasket and tb go.

bobbyd

iTrader: (10)

you could be right on it being the scanner for a downstream sensor. but the car only has the 2 front ones.