About cold start tuning

[imponte]

Hi. Car is 2010 ss with l99 engine, cold air intake and cattles exhaust. I had a dyno tune. We canceled the front oxygen sensors because 1 of them was faulty. My tuner said it'll ok without them. I think my car is always running on open loop, and cant trim the fuel. I'll replace the 02's and will retune. But my question is not that. First start on the cold weather engine starting but immideatly dying after 1-2 seconds. But if i press the gas pedal little bit, it doesnt die. On second start, it totaly fine. This issue was 2 months ago. After that my tuner retune it. Now it never dies on first start but it starting like little bit coughing. I checked the afr, and it was 9.5. It slowly rise to 14.6 as the coolant temperature rise to 185 F. I think my tuner lowered the afr due to engine die on cold start. Do you have any opinion or experience? Thanks

[imponte]

Any thoughts??

[dreksnot]

Generally it's air or fuel. It could perhaps be Startup Airflow. That's a airflow-over-time (up to 4secs) after startup setting depending on time since last engine shutdown (that's probably why didn't start on first crank but did on second (it reset to zero)). I had to increase mine with my engine build. Could also be Cranking Fuel off. Then there's Startup Cranking spark timing...

[imponte]

Originally Posted by dreksnot

Generally it's air or fuel. It could perhaps be Startup Airflow. That's a airflow-over-time (up to 4secs) after startup setting depending on time since last engine shutdown (that's probably why didn't start on first crank but did on second (it reset to zero)). I had to increase mine with my engine build. Could also be Cranking Fuel off. Then there's Startup Cranking spark timing...

Thanks, i will check that