Cammed LS3 startup issues.

Im tuning a friends car to idle and drive good. It idles fine, and it also drives great already, It does not stall on deceleration or hard braking. But on startup it just starts and dies right away. It is really weird because before it was starting right away. I even tried the previous tune and no change, still starts and dies. I went back to my current tune and added airflow, tried adding spark, tried more fuel but nothing makes a difference.

I was thinking maybe the throttle body is bad?? Another friend had similar issues with his ls3 throttle body and switched for a truck throttle and stopped having issues on start up.

Anyone have had this problem before? I feel like i tried everything and it acts the same. Might it be the throttle body?

MAF or SD?

You can log throttle blade position to see if it's moving reasonably close to how it should

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Originally Posted by schpenxel

MAF or SD?

You can log throttle blade position to see if it's moving reasonably close to how it should

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MAF. I did log some of the start ups, do i look at the tps? Or do i have to add another channel?

I think i have figured it out. Startup airflow around the temp the car wont stay on is reallt low. I think that might be it but i remember bumping these tables up. Either way ill try it later today and hope it works.

On another note i have been have trouble with the car dying on idle when the ac kicks in. In gwar the car wont stall when the compressor kicks in, but If we start the car with the ac on it will stay on. It is not controlled by the ecm and is wired as a standalone unit since this engine is in an early 70s car. Is there anything i can change to keep the car on when the ac kicks in?