94-95 Mustangs Tuning Emissions
From Mustang-Tech
The HC is indicative of a rich burn, a VERY lean burn, or a cam that's got too much overlap and is letting raw fuel slip out the exhaust. If this is the emission you are getting nearly dinged on, then you can probably help this by delaying the injector fire until after the exhaust valve has closed. EEC Analyzer can help you calculate out an Injector Timing table to accomplish this.
CO is indicative of a rich burn...where there just wasn't enough O2 to turn the combustion into CO2. Burning leaner should be the cure for this one. If you are getting dinged with this one and the car runs Closed Loop, you may need new HEGOs or you may need to play with the HEGO Bias/Amplitude settings to force a slightly leaner burn during Closed Loop.
NOx is indicative of a HOT burn generally caused by being too lean. Your NOx goes up if the EGR isn't working. If this is the emission that was just scraping by, then you can increase the EGR percentage used during the 1500-2500 RPM range. You don't want to go excessive here, but increasing it some, especially with a Cobra tune, should lower the NOx emissions by a fair amount. Another thing you can do is put Kerosene or Alcohol additives to a 1/2 tank or less. Kerosene burns slower. Alcohol burns cooler. Either of these should lower the burn temps and reduce NOx as well.
Tips:
- Hotter cars run more efficient -- raise fan on/off temps
- Decrease spark advance
- Make sure your O2 sensors are working correctly and MAF element is clean
