Spark advance.

[Aaron1989]

I don't understand exactly what you're saying but I get what you're getting at. I understand that tuning is not just making one adjustment and going with it. See I followed something the driveway engineer put on YouTube and my truck wouldn't even start. Maybe has something else wrong I might try again tomorrow

[steveo]

well if you advanced the normal timing table, then it probably wouldn't affect start up
i dont know your specific computer but usually there's a 'cranking timing advance' table or something
what exactly did you change?