^^^x2!!

 

What you are doing when you remove the code is actually telling the computer that when the catalytic system is not performing as it should "do nothing" instead of "trigger MIL" so the computer still sees the 2 sensors being the same, but thinks that is ok. When they plug the car into the emissions computer it will report everything normal, because you have changed what normal is.

 

But I thought that HP tuners or any tune will shut this code off forever??
You mean to tell me it could come back? Because I was thinking to get a tune, but I do not want to go back and fourth, shutting off "check engine" lights and/or etc.......

 

Here is a link to an o2 simultor, just 1 of several still available online
http://www.o2simulator.com/?gclid=CL...FeZL5Qod3VR9Fg

 

check this out, they claim 96% sucess, but you can make it your self real cheap. Buy a pair of antifoul spacers at most auto parts stores, drill one to 1/2" for sensor to fit, stack them and instal sensor easy!
Cost $4? what have you got to lose?

 

http://www.autotube.net/

 

The HP Tuner will remove this forever. I own an HP Tuner and can turn anything off that could trigger an engine light. I just wish it could turn off the tire light since I have changed my rims.

 

I love my state(CA)but hate all the damn laws about addin and removin parts 2 your own ride...all other 49 states got it made,looks like no dp or catless on my ride...

 

Massachusetts has similar tougher laws now, but when it comes to emissions if the OBD says everything is good on the late model cars, than you're good to go.

Thank you HP Tuners - not that I drive my car on the road anymore...

 

FOund this on another forum:
http://www.grandprixforums.net/f65/r...ewer-7092.html

Tuned on an '05 Monte SS L67 the other day. Owner installed a ZZP DP to delete the cat and he also removed the rear O2 (even tho there is a bung in the DP).

Anyway he brought it to me for a tune. Went in a disabled the CAT diagnostic code as well as the rear O2 diagnostic codes. Went for a test drive and discovered that after driving the car for a couple of minutes the ST and LT fuel trims would both max out and the car would go pig rich and stay there.

Talked to TrannyMan since he has heard of this before and found out this problem seems to exist with only the 01-up PCMs. This got me thinking, and then I remembered back to my GM OBD-2 training at the dealership -- reading about this diagnostic self-test the PCM runs to determine if the rear O2 and cat are both working as desired. Basically the computer commands the fuel trims rich for a while and expects to see the rear O2 signal to eventually go rich after the cat gets saturated.

Well, as it turns out if you remove the rear O2 and disable the trouble codes for it, the computer seems to still want to run this diagnostic but will never stop running it. I had the wideband plugged into the car I was tuning and the AFRs were ranging from 10.5:1 to 11.5:1 pretty much all the time unless you floored the gas or decelerated from a high speed. So obviously this is not good.

I went back into the programming and turned the trouble codes back on for the rear O2 (but instead set them to "No MIL" just so the check engine light wouldn't turn on) and did another road test. Same thing happened again, the rich condition came back as the diagnostic test ran but this time it only lasted for about 20 seconds before the computer set a P0140 code (rear O2 not enough activity) and then the fuel trims and AFRs returned to normal for the remainder of the drive cycle.

I think what this diagnostic may be called is a "Cat Diagnostic". On some older vortec truck cals I have the ability to tune, I can actually disable this diagnostic. So now I am working with my tuning software vendor to see if we can add this ability to 01-up L67 and other V6 applications. Just thought I would pass this info along to you guys for reference. Of course I will let you know what we come up with.

Before I changed my DP to the ZZP I went from 30-32 to 26-28. I am checking inot this more.

 

picked up a catless DP from hogan performance in topeka ks today.... excited to put it on yay

 

Nice!! You'll love it!!