Your car will first have to pass visual inspection. That means it must be fuel injected with all the orginal smog equipment present and functional. If you don't have a catalytic converter H pipe, get one, since they will likely look for it. Very few cars will pass the snifffer test without a good set of cat converters.
Once you are able to pass visual inspection, here's some tips to help get you into the acceptible emissions range.
How to pass emissions testing:
1.) Make sure all the emissions gear the car was made with is present and connected up properly. That includes a working Thermactor air System (smog pump) and cats.
2.) Make sure that you have fresh tune up with spark plugs, plug wires, cap, rotor, fuel & air filters. An oil & filter change is a good idea while you are at it.
3.) Dump the codes and see what the computer says is wrong…
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.
4.) Post the codes and get help to fix them. Don’t try to pass with codes not fixed. Clearing the computer just temporarily removes them from memory, it doesn’t fix the problem that caused the code to be set.
5.) Be sure to do the testing on a hot engine. Drive for 15-20 minutes prior to taking the test to get operating temps up into the normal range. Do not shut off the engine while waiting for your turn on the test machine. An engine up to full operating temperature puts out fewer emissions.
High NO - high combustion temps - retard timing, check EGR for operation.
High CO - EGR isn't working - fix it.
High HC - fuel mixture too rich - check O2 sensors, smog pump, and cats. Clean MAF element. Do the ethanol thing as suggested.
My case is ... rather complicated (see sig). Essentially the beast is now carbed. I am thinking that the car is OBD I - 1992 LX. That means I must pass the sniffer and the visual in the New York City Metro. I have the full STOCK cat system installed, w 02s.
TO PASS :
Soooo, that either means
1. Pay for the pass on visual and tune the car down (if even possible) with the carb. The car then can ideally pass the dyno sniffer with the tail pipes loosened. This is understanding that the car is NOT connected to the system at the ECU.
IF FAILURE,
2. Install the ECU and eliminate all codes via existing means, and have it connected to the dataport and pray with above detuning/ breathing.
3. Drop $$$$ go EFI, and have a tune for emissions to pass.
There is almost no way you will pass the sniffer test with a carb'd engine. Crazy Pete, the resident Stangnet die hard carb guy did his best and failed. Pete is probably better than average with carbs and he could not get it to where the car was driveable and still clean enough to pass emissins testing.
Loosening the tail pipes won't do anything but make an exhaust leak. It will not suck air into a pipe that is pressurized inside.
vristang has a fuel injected 408 that has all the smog equipment working. You can be sure that it is just as fast as a carb'd 408. PM or email him for his input.
there is a place in queens, i know is near shea stadium, you have to go up to the guy and tell him you need to pass inspection no that you want to do the inspection.
and if u are willing to come to long island, there is a place near me also, but is like 150 or so....
either way let me know, i have an 86 that will be carb in 2 weeks or so