M6WS6

iTrader: (1)

Alright, I have had enough and am hoping some experts here can help before I take it in.

My car started getting worse gas mileage, so I used a OBDII that Bluetooth to my phone and noticed one of my O2 sensors volts was bouncing around while the other stood relatively still (bad one was jumping around like crazy from .0-.9, the other was around .4-.6). I purchased and replaced the O2 and the problem still existed, did the same thing. I swapped the O2 sensors and the problem followed the O2 sensor to the other side, so figured I had a O2 sensor that was new that was ****. Well, I am on O2 #4 and still having the same issue. I swap them from side to side and problem always follows the new O2. Beginning to think something else is up, but not sure what.

I have heard of issues finding O2 to work with LT's etc., but this is ridiculous. Tried Denso's, and Bosch's. I am not getting codes, but the car isn't running quite right, and the mpg's dropped. I cleared up an exhaust leak by the exit of the header and re-sealed the exhaust up and put new plugs in. Car was tuned by Speed Inc. in 2005, and I haven't changed anything motor wise since.

I live in Iowa so this is my time to drive my car, if I cant get a direction sooner than later it is going to the shop so I can enjoy it. Been a problem from the start of the year, and was not able to work on it for over a month due to surgery.

Thanks,

Trevor

Bowtie316

iTrader: (1)

The one that is not swinging from .0 to .9 is bad, or called a lazy o2. you should have changed the other one out.

M6WS6

iTrader: (1)

It moves, just not drastically as the other. It will go to .9 and drop down to .3 as it needs, the one side literally jumps from .9 to .0 in a split second while on a flat road using cruise control... I would imagine there is not that much change with the motor a/f while holding steady RPM down the road with CC....

Not saying you are not right, just dont see it I guess. With steady RPM and flat road, it just dont believe it should be bouncing from .0 to .9 and back and forth in split second times....

Can anyone else comment?

Rise of the Phoenix

iTrader: (27)

Does the car perform or sound different?

M6WS6

iTrader: (1)

Yeah, it seems to be making a difference at times when driving around. Sluggish down low for sure, and once in the higher RPM it seems to be better but not great. Not always running bad, not always good.

Bowtie, you might be right on that, I started thinking about it more and I guess with how many readings it takes a second, I might be seeing some of those, assuming I should be seeing it always around the .45...With how many per second it takes, it is pry reading those #'s and bounces around like that.... If that is case you will make me feel like a complete idiot.lol. Fairly sound on cars and work on all my own stuff, but I might have been miss thinking this one too. I will have to try tonight when I get home and see what happens when I put the another O2 on the other side...

Bowtie316

iTrader: (1)

While I don't think it would be normal for the o2 voltage to jump between .0 and .9 with every swing, what you want to see is the voltage moving and moving quickly. I would say it is more common to run between .250 and .800 an occasional jump to .0 or .1 and .9 seems fairly normal to me. One that only sees .4 - .6 would be suspect.

Got to remember to that when in closed loop, the fuel is constantly metered to go rich then lean then back to rich. This happens very fast in real time.

M6WS6

iTrader: (1)

I will give it a shot tonight. The way I was looking at it is it should be in the .4-.45 area for optimum, but kind of forgot how fast/often O2's read and I could be seeing each reading that makes up my .4ish tune.

It doesn't dip to .0 very often, just every now and then. The one I thought was bad would be around .4-.6 and jump to .9 with the other one, but hardly dipped down below. I can see it your way as well. Will be looking at that tonight, and hopefully follow up as soon as I figure it out. Thanks for the help.

If anyone else has input great, but hopefully I was just slapped with the stupid stick and have this narrowed down.

gagliano7

Here is a log of my 5.3 with lt headers 5 speed manual in a 1992 chevy pickup. Look at my 02's. Truck runs perfect.