Hi guys I've run in to a problem. First of all this is for 730 8D.
I'm running a heated O2 in the collectors. Int is 108 and I did a plug reading. They are burning perfectly, but how can that be? I have no vacuum leaks, if I did then the Int wouldn't be that rich. Question is "If I am using a heated o2 should I change the mv of the 02 sensor constants in the bin? I am using AUJP, and the only things I've changed are the cooling fans, highway mode enabled, disable EGR, no air pump. VE, spark advance and most every thing else are still stock.
I've read just about everything, including posts by 11's or bust, Grumpy, Rbob, Trax, saturn, funstick, and countless others.
Somebody help me.

Domenic

 

The most obvious thing is that you wired the O2 sensors incorrectly. Make certain that the center wire on the O2 sensor connector (or the wire that is different in color than the other two) is hooked up to the O2 signal wire from the ECM. You may have wired the that O2 signal wire right into the 12V power circuit- the ECM would be seeing a stuck-rich condition and is trying to lean it out.

You shouldn't have to mess with the O2 constants at all. The heated sensor operates just like a standard one.

 

Thanks for replying.
I was thinking that I might have wired it wrong as well, but it pretty hard to screw that up since every ac/delco 02 sensor I have ever seen, the sensor lead is always purple, plus my painless harness was labeled that way to. I was just wondering if I might be able to tighten up the swing point of the sensor itself.
Domenic

 

If you're certain there are no malfunctions in the engine such as a misfire, then it looks like you have some tuning to do!

I don't know what mods you have on your engine, but it the VE and spark tables may need to be tweaked.

 

Hi ULTM8Z
Thanks for trying to help me out, I really appreciate it. My engine is pretty stock, pulls a good vacuum at idle, but to be honest with you I really don't know whats been done to the motor, It was with the car when I got it, and it was carburated. I wonder if it has anything to do with the fact that I don't run cats. What do you think?
And it really does run excellant. Maybe I should just leave it, but the more I learn the more I want to play. I think I going to send it to the dyno and throw a wide band on it. I know it's the best bet, but I like to try and fix it myself.
Domenic

 

If your running 108s that just means the ecm is doing a large correction to get to Stoich.. So the plugs reading correctly, just lines up with what the ecm is commanding AFR wise.

Since you've set no codes, the ecm thinks things are within allowable tolerances.

If you had a small vac leak, then the ecm would be having to raise the BLs.

No need to change the O2 constants, for what you've mentioned.

 

You know what would be interesting? Finding a hac that uses a heated 02, and finding out what the mv constants are set at.
I tried looking at a EE, but maybe TC doesn't think it is that important. Come to think of it, maybe it's not important.
Dom.

 

Hey Grumpy thanks for the input. Under what circumstances would I want to change O2 constant? Sorry if that's a stupid question.
Domenic

 

I believe you'd want to change the O2 constant if your engine is setup such that it doesn't run optimally at 14.7:1 AFR. Some "built" engines (especially at low rpms) may like to run at sub-14 AFR's. So the owner may adjust the ECM to shoot for a, say, 14:1 or 13.5:1 in order to make the engine happy.