Possible o2 Problem, Need Some Confirmation

[Street Wolf]

Alright, so first off...

Took my car out today with the tuner hooked up too it. Scanned a lot of things but the one thing my buddy riding with me noticed the most was my o2 sensor was fluctuating at idle, and even when accelerating quite hard. Regularly even going down as low as 50-60 at times before hoping back up into the higher triple digits one again.


Just does'nt seem right to either one of us. I'm assuming it's not normal to have it drop all the way into the double digits under any circumstances, right?

[Sabrewings]

Mine does that at idle or cruise.

[Iron Indian]

My stock one did that when it was dying. I replaced it and it solved the problem. It should never get in the double digits, at least it never does on my car anyway. I'd say try a new O2 sensor either AC/DELCO or Denso NOT Bosch...

www.sparkplugs.com and coupon code "dodgetalk" (may not work anymore). My Denso O2 ran me $45 shipped to me w/ the coupon code....

[Sabrewings]

My O2 sensor is less than a week old (brand new out of the bag from a dealer) and it still does it.

Granted, I may have a vacuum leak...

[Street Wolf]

Mine does that at idle or cruise.

My stock one did that when it was dying. I replaced it and it solved the problem. It should never get in the double digits, at least it never does on my car anyway. I'd say try a new O2 sensor either AC/DELCO or Denso NOT Bosch...

Spark plug, Spark plug wire, spark plug gap, spark plug cross reference and ignition wires at Sparkplugs.com and coupon code "dodgetalk" (may not work anymore). My Denso O2 ran me $45 shipped to me w/ the coupon code....

Awesome. Thanks, did'nt think it was ever suppose to get that low. Just trying to fix every possible thing I can becuase I know something is creating a hell of a lot of knock.

[Sabrewings]

Just trying to fix every possible thing I can becuase I know something is creating a hell of a lot of knock.

I'm getting the same problem!! And I, too, see readings dip into the doubles, then back up. I'm suspecting a vacuum leak, possible a lower injector o-ring and am investigation Saturday.

[Iron Indian]

Vacuum leak will do it too from what i've heard. I donno for sure though.

Street Wolf, i'd try a new O2 and see what happens. Maybe a little RTV from the blower install made gases go out the exhaust to damage the O2 sensor? I've heard of that happening to people, even on brands of RTV considered sensor safe. That could be a possibility, i've had good luck though (knocks on wood). Maybe its just a fluke thing, either way I think your O2 is bad. Good luck, let me know what you figure out.

[Street Wolf]

I'm getting the same problem!! And I, too, see readings dip into the doubles, then back up. I'm suspecting a vacuum leak, possible a lower injector o-ring and am investigation Saturday.

Weird, is your car idling rough or anything?

I'm pretty well stuck as of right now. I haven't the slightest clue where to begin looking for problems. As of right now I actually think I'm just going to take everything off back down to the intake and re-due it all over again just in case something was accidentally missed becuase my car runs, drives, idles perfectly fine, but as soon as I even tap the gas I have outrageous KR. Even with the 3.2 pulley I put on it just to see.

[Iron Indian]

Hopefully this aint a dumb question Street Wolf, but after what Sabrewings said, are you sure you have no vac leaks? Whats your IACs at warm idle w/ acc off? Whats your gauge read in hg vac at idle? You probably already checked this stuff and know its good, but I figured i'd throw it out there though. It easy to miss those things...

[Sabrewings]

Weird, is your car idling rough or anything?

No, it acts fine.

my car runs, drives, idles perfectly fine, but as soon as I even tap the gas I have outrageous KR.

This is too weird, as that's exactly what I'm seeing. I've also noticed it isn't as bad when the engine is cool (which I have a theory about that, too).

You can see my summary right here:

http://www.grandprixforums.net/f17/m...e-kr-5040.html

Iron, what should the IAC be showing etc so I can check that stuff out...

[Iron Indian]

I hear about 50-60 IACs are right . My Setup i'm runing around 55 IAC and 19-20 in hg vac at warm idle.

[Street Wolf]

Hopefully this aint a dumb question Street Wolf, but after what Sabrewings said, are you sure you have no vac leaks? Whats your IACs at warm idle w/ acc off? Whats your gauge read in hg vac at idle? You probably already checked this stuff and know its good, but I figured i'd throw it out there though. It easy to miss those things...

Right now I am fairly certain I don't have any vacuum leaks. It's possible though.

I've got a scan I did earlier saved on my laptop. I'll just grab it in a moment and see if I can get it posted up.

No, it acts fine.



This is too weird, as that's exactly what I'm seeing. I've also noticed it isn't as bad when the engine is cool (which I have a theory about that, too).

You can see my summary right here:

http://www.grandprixforums.net/f17/m...e-kr-5040.html

Iron, what should the IAC be showing etc so I can check that stuff out...

Strange.... for all I know we might have pretty much the same problem. Hopefully it won't take long to figure them both out.

[Street Wolf]

Wait......... let me check something real quick.. be right back.



Edit- Actually, I'm just going to hop on the internet in my car.

[Street Wolf]

Okay now.... scanning as we speak. At warm idle.....


EVAP: 15.69%

VAC: -8.23

MAP (INHG): 42.04

MAF: 2,456-2,479

IAT: 61

A/F: 14.7

Injector PW: 1.77-1.88

LTFT: 16.41%

[Sabrewings]

VAC: -8.23

What value is that?

[Iron Indian]

LTFT is at 16.41%? Vac -8.23? Sounds like you have a hell of a vac leak dude! Get some carb cleaner, do some searching Something ain't right on.

Whats your IACs at warm idle?

[Street Wolf]

What value is that?

Vacuum, not nearly the number it should be.

LTFT is at 16.41%? Vac -8.23? Sounds like you have a hell of a vac leak dude! Get some carb cleaner, do some searching Something ain't right on.

Whats your IACs at warm idle?

So I've noticed. lol Wasn't looking at that earlier.

IAC is around 55 warm idle.

[Iron Indian]

55 ain'r bad..... but that -8 and the 16% tells me you got a vac leak somewhere. I'd check some lines out if I were you, or check the S/C gaskets....

[TDCRacing]

the o2 flucuates like that at idle and cruise because of minute inconsistancies in the tune. It's normal

[Reptile]

55 ain'r bad..... but that -8 and the 16% tells me you got a vac leak somewhere. I'd check some lines out if I were you, or check the S/C gaskets....

X2 right there. Even a small pinhole can create LTFT's in the +12-16 range....a big leak like a TB gasket or SC gasket not properly seated will peg it at 20.