Black Smoke (Rich Mixture)

Check the following:

• Check fuel delivery system. Go to TEST HB, step 1)  (Natural Gas models), or go to TEST HC, step 1)  (all others) under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.
• Check secondary ignition system. Go to TEST JB, step 1)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.