bret Great Site! Have 89 full size 5.7 TBI, Burns Rich runs well,Fuel Pressure Regulator? Plugs looked very clean and uniform. Approx. 30,000 miles with new injectors. HC GPM 4.38, need 3.0, Failed Emissions Test. Thanks!

 

We do those emission tests here in BC. What ive done in the past is run the gas down real low and pour a gallon of Methyl Hydrate into the tank, its alcohol and is clean burning. It dropped the HC emissions by 100 points which was enough to pass the test, I imagine 2 gallons would have lowered it even more. The stuff is about 12 bucks a gallon at the parts strore. You should also see if you have a fuel leak at your injectors maybe? If they are dumping raw fuel as well that would explain the high HC readings too. What condition is the cap and rotor and plugs in? A crappy burn makes for high HC readings too.

 

Does it have an adjustable fuel pressure regulator on it? You can check the fuel pressure, however you have to install an inline adapter to do so.

When was the last time a tune up was done? I'm guessing that the O2 sensor is wonky or you have an exhaust leak ahead of the O2 sensor causing it to read a false lean condition and richen the fuel mixture.