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View Full Version : OBD1 and OBD2 Knock Sensor...



BlackWidowSS
04-14-2012, 01:08 AM
I converted my 97 SS over to OBD1 while I lived in Wyoming...no emissions there at ALL. I recently moved to Colorado...STRICT emissions. They are going to do a test on my car and I have to convert my PCM back over to OBD2. The only things I changed was I removed my rear O2 Sensors, and I added in a 94 LT1 Knock Sensor and installed the 94 PCM. Everything is great EXCEPT for the fact that "reverse engineering" my car is illegal in...say....50 states. Oops.

SO, now I need to pass emissions...which means I need to install the OBD2 PCM, Rear O2 Sensors, 2 Catalytic Converters, an actual exhaust system (Previously it was LT Headers to an LPP ORY to an SLP LM1 dumped at the axle), mock up my A.I.R. system and I need to tune the OBD2 PCM.

Now don't get me wrong...I HATE the LT1 OBD2 and I DO NOT plan on keeping it...therefore I am copying one of LS1Tech's esteemed member's threads almost to the letter...the ONLY change I am making is instead of 2.5" QTP Cutouts, I am doing 3" QTP Cutouts and I will have 3" to 2.5" reducers that will take it down to the 2.5" pipe AFTER the QTP's...the cutouts can be taken off and the reducers can be used BEFORE the CATs since the CATs will be 2.5". Here is the link: Project Bad Ass True Duals complete. Final pics inside... (http://ls1tech.com/forums/lt1-lt4-modifications/1168724-project-bad-ass-true-duals-complete-final-pics-inside.html)

My question is...when I do this, do I absolutely HAVE to change that Knock Sensor??? If I don't what will happen exactly?

Basically what I will be doing is throwing my ALL of my emissions stuff onto the car and having my tuner set up a VERY conservative "emissions" tune on the OBD2 PCM. Once that is done, I will take it back out and re-install the OBD1 PCM to rive it to the emissions shop. Once I get to the shop, I will remove the OBD1 PCM and install the pre-tuned OBD2 PCM. I will do my emissions test, and upon passing I will stop in the lot and remove the OBD2 PCM, re-install my OBD1 PCM and head back to my shop where I will remove all of the emissions crap, throw it into storage, re-install the QTP Cutouts and I am good for 2 years.

Thoughts, questions, concerns? Anything that I missed or am overlooking? Thanks in advance!

waggl1
04-14-2012, 04:27 AM
Just keep the camaro registered in Wyoming and you can be ok just deal with tags etc. My 94 was registered in California but I changed it to south Dakota and sent paperwork if you just keep license and reg. In Wyoming you'll be ok I mean the upa can't say much because you're a registered driver for Wyoming etc and you abide by there emissions

waggl1
04-14-2012, 04:29 AM
Funny thing I live in Laramie now

Jloshotz
04-17-2012, 07:29 PM
Pretty sure the knock sensors ohm out completely different from OBD1 to OBD2. Also wanna say OBD2 has two sensors, one on either bank. Pretty sure you'll throw a code. Hopefully someone else can chime in to confirm.

bRock
05-05-2012, 09:44 PM
I'm doing a build on my 97 LT1; talked with several rod/tuning shops (very reputable, I might add), and they've ALL stated that I can pass emissions with a tune! I'm planning on deleting all emissions crap, including cats. Seems that may be cheaper/easier!