Raising switch points commands a slightly richer AFR whereas lowering them commands a slightly leaner AFR. I'm not so sure the location of the switch point has much to do with the performance of the sensor.

 

so instead of stoich at 14.6 @451mv the car depending on which CL mode it is in will be at whatever AFR the voltage is set at?

now wait, the performance of the sensor...if it truly is performance; that would tell me that my stock 02's are going bad
AND i got 2 bad corvette 02s as they do the same thing?

i know **** happens...and i know manufacturers **** up, its all a percentage error that you get out of making any damn thing these days; but i know since after i turned off all of the emissions crap and everything that it just started doing it. the car has 24k miles on it, stainless steel headers from kooks 1 3/4 and for 20k miles i didn't have a problem; haven't sprayed it or anything

 

My theory is O2 sensors act up for two reasons when you install LT headers. 1 - Low/Cruise RPM exhaust velocity is slightly lower than stock because the diameter of the tubing where the O2 sensor is located has increased. 2 - Temps at the point of the exhaust where the O2 sits now are lower than stock. When I mentioned switching performance, I'm refering to how many times the O2 jumps from ~300mV to ~700mV. When O2's sit on the 300mV side, positive STFT's are introduced. Same goes with negative STFT's for the 700mV side. The average of these is where your LTFT's come from. If you change the switch points, is that really going to change how frequently the O2 jumps up and down? I don't think so. I think that problem exists because of the lower temps, which is why some suggested a sensor like the Vette rears. Just for kicks, let's say your O2's worked perfect. Lowering your switch points effectively changes the averages to run leaner in this case. With lower switch points, the O2's will report back voltages on the higher side more often than on the lower side of that switch point. This will prompt the PCM to pull fuel to lean you out, which effectively brings the reported voltages in line with the switch point. If you look at stock tunes, you can see the engineers built in a bit of a pseudo lean idle by doing this. The point I'm driving at is, all of this doesn't really affect how often the O2 jumps up and down. I wish there was a straight up solution to this, but as far as I know there isn't. My experience with 2 other cars show the Bosch OEM replacements are junk though. That's why I asked if you're running their sensor. Both of my friends experienced significantly more swings in LTFT's after the install of the Bosch O2's. One is actually running a factory stock sensor in B1 and the Bosch in B2. Watching the log, it's fairly obvious since the B1 LTFT's are -3~+1 and B2 go from -7~+2. I think the stock ACDelco's are best, but with LTs won't last as long vs stock applications (maybe the heaters burn out faster over time?). Either way, switch points aren't the fix to this problem if you ask me.

 

why did it take 20k miles for something to happen

 

That's my guess...

 

the heaters try and keep it up hotter so they wear out quicker? i believe that... you know anyone else that has had this problem? thanks for all of your replies man, its been great talkin to ya and helping me figure it out

 

np...

 

Nice cut and paste. I appreciate the good press.

Elmer

 

haha, figured people would want that.

 

Sorry, I didn't realize copy and pasting factual information to aid others, wasn't a good thing to do. Let me fix that for you.

The information that I posted is courtesy of eboggs_jkvl, who is an administrator on ls2.com

ZL1Killa, this forum is great when you get responses like these from SSpdDmon, good luck getting everything straightened out.

 

No, it is a good thing to do. Usually, you note where you got the information as a courtesy. I typed that out and displayed it for public use, you guys are the public. What really would have been nice would be to link to the thread as it actually shows how to disable those codes with screen shots of EFILive and LS1 Edit. Had I had access to the beloved HP Tuners, I would have posted those screens as well. I'm not making waves. I always give credit where credit is due. When people on LS2.COM use ls1tech as a source, they usually link to the thread where the information is found. I see no reason the common courtesy couldn't be returned.


Now, get yer knickers out of a wad and enjoy the day!


Elmer

 

aight guys, had a problem with the insufficient switching in a different area, up in the higher CL mode....still trying..

 

mike, thanks for taking a look at my tune and logs... let me know if you need anything.

and guys, i will keep you posted

 

Guys found out MY problem.
Quote from WS6FirebirdTA00:
"Find out from the EFI boys if they have a table which controls the amount of fuel the injectors shoot to make the o2s switch. In HPT its called proportional fueling. This is where you problem is, nothing with the switch point. I would put them back to stock and set up a scan so you know at XX airflow what mV you see for the AFR you want. If you find this table we can take care of it, the problem is coming from the injectors. The computer is commanding large fuel swings, which with bigger injecotrs is even larger. This makes the o2 readings rail at idle (you can see that in the log)."

i will soon find this out from EFI LIVE.com and find out where that table is. i was noticing that my 02 mV readings were looking a little funny from normal. Hopefully this is the problem

 

DOES ANYONE KNOW? read post above

 

Guys found out MY problem.
Quote from WS6FirebirdTA00:
"Find out from the EFI boys if they have a table which controls the amount of fuel the injectors shoot to make the o2s switch. In HPT its called proportional fueling. This is where you problem is, nothing with the switch point.

 

Ive been getting the same error message [HO2S Heater Performance Bank 1 Sensor 1 (SES) (Pending) (Old) (History) (Current) (Immature)]. It has happen probably once a day since i put my cam/heads/intake on the car. But i noticed when it happen last time my car was idling for about 2-3 minutes and i then decided to take off, thats when i thought i heard a sound come from underneath the car. Someone made a suggestion on another form that a leak in the exhaust could make the O2 sensor do this.

What do you think?

 

no...not a leak in the exhaust unless its HUGE or really big...and after the cats(or not cats in some cases)