hi ,
Subject: Black Smoke On Cold Start
Models: 2009-2012 Buick Enclave
2009-2012 Buick Lacrosse
2009-2012 Cadillac CTS SRX STS
2010-2012 Chevrolet Camaro
2010-2012 Chevrolet Equinox
2009-2012 Chevrolet Malibu
2009-2012 Chevrolet Traverse
2009-2012 GMC Acadia
2010-2012 GMC Terrain
2009-2010 Saturn Outlook
2009-2010 Saturn Vue
with 3.0L LF1, LFW and 3.6L LLT, LFX engines only
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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Concern:
BLACK SMOKE ON START UP ONLY.
With the introduction of direct fuel injection systems, GM has revised the cold start control system to reduce cold start emissions. Quicker catalytic converter heating helps meet the ever changing emission requirements and improve fuel economy.
Recommendation/Instructions:
A dual-pulse injection strategy is utilized during engine cold start to reduce the time required to bring the catalytic converter up to operating temperature. This split injection strategy lasts for about 60 seconds on cold start.
This process will cause the customer to see increased black smoke or soot during cold start and should be considered normal.
This cold start strategy is enabled upon start up after the engine has soaked for sufficient time such that the catalytic converter requires rapid reactivation.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
:beer: