Hey, I was wondering if you could pass an emmissions test with long tube headers and no cats in Tennessee. I know the last time I was in there all they did was check my gas cap and read the pcm for trouble codes. They didn't even look under the car, pop the hood, or put the sniffer in the tailpipe. I am pretty sure I could have passed last time I was in there. Now I hear that they are putting into effect stricter laws. My buddy with a 3/4 ton 94 GMC truck was previously exempt. Now he has to get it tested.

 

If they just do a sniffer test, then you can still pass. Just make sure the car is tuned well. It wouldn't hurt to run some GM Top Engine Cleaner through and some Techron in the gas. Make sure you're not running much spark advance as that will create more hydrocarbons. This has been done many times on a variety of cars including some of those 454SS pickups.

Jason

 

okay, but they don't do sniffer tests on OBD II cars. They do sniffers on OBD I and carberated cars. All they do is scan the PCM. Since I won't be running the AIR pump or EGR, will that show up on the computer?

 

a couple bottles of rubbing alcohol on $5 worth of gas will blow clean as a whistle, then hurry to the gas station and fill the tank up. Yes, missing EGR and AIR will show up on your PCM scan.

 

well if I get long tubes I'll have LS1 edit done, or a custom PCM tune that will delete the AIR and EGR from the computer program. So will it show up on their codes scan, because it shouldn't show any trouble codes with these systems.

 

I'm not sure about this, but deleting codes on LS1 edit basically disables the computer from recognizing or "knowing" what 02 sensors, EGR, or AIR is and it not able to tell the emission computer it has any data on this stuff.

Jason

 

The way I understand it is that they just scan for emmissions malfunction codes. If the EGR & rear O2 codes are disabled then no malfunction codes and a pass.

 

the computers at most emissions sstations will register a "System not ready" when they scan PCM for the air & egr delete. They'll try again and just pass after that as long as you blow clean. I had like 6 codes when I went to do emissions and they passed me anyway because I was way under the emissions "standards" they set. Low voltage for o2 sensors 1 3 & 4, CAGS system malfunction (big frickin deal), and AIR system malfunction, EGR system malfunction. They passed me anyway. SInce then I've had the codes deleted. Took like 10 minutes.