Emission Failure
 

Hey folks,

Need some help with emissions passing on a 84 mustang gt convertable. All stock, runs great but this is the first year it didn't pass out of the five years I've had it. I'm in Georgia and the passing and non passing grades are as follows:

Reading Allowed Result
HC ppm 309 174 fail
CO % 3.67 1.12 fail
NOx ppm 749 1258 pass
RPM 900 2500max
CO+CO2 % 14.46 6.0min

Fuel cap test pass

please help, i've got 30 days to make any changes so that i can retest at the same place for free instead of another 25.00 (the rich get richer).

thanks

Emissions tips
 

I believe that Georgia went to the dyno test method this year and that may have tripped you up.

Does the engine burn any oil - and did you prepare for the test? Warm-up the engine and give it a good run before pulling up to the testing site. Have a fresh oil change, too.

I don't have any specific advice except to perform a total tune up, including new spark plugs, plug wires, cap & rotor, air filter (important), PCV, gas filter and adjust the timing to stock (10 degrees BTDC). You may want to have the carb checked, too. This should help a lot - if you haven't done it all already. Use 87 octane gas, not hi-test.

If you've already done the tune-up, have the catalytic converter checked for effectiveness.

I believe that if you improve substantially in the re-test you can receive a waiver. This may be your best bet, especially if you just miss the mandated limits. Others may have specific tips but this is the standard prep for emissions tests.

I thought I did but apparently not. The plugs were changed about 4 or 5 months ago but just plugs. Wires have been on for about 2 to 3 years and it could use a new dist cap and rotor and I probably have about 2000 miles on the last oil change. Fuel filter, pcv, air, and breather filters are all new. I didn't run it for a real long time before testing maybe about 15 minutes and had hi test gas in it. And my driving has changed for alot of freeway driving (30 to 40 miles one way to work) to 3 or 4 miles one way on the back roads. I sure could use any other help you may have and thanks for the previous info, I will definitely follow up with that, just didn't know if I needed to look for specifics within the emission system itself and yes ga does use the dyno but I passed it last year.