hard cold starting LS7

Gents,

not sure if I am on the correct sub-forum for this one, but I have a problem with a LS7 cold starting. Involves lots of cranking, cracked open throttle and sometimes backfires, periodically causing a broken starter ring gear.

I'm running an LS7 throttle body converted to cable drive. There is no idle air bypass. Car has been professionally dyno tuned and runs great when warm, but cannot seem to get it in a state where it starts easily when cold, and it also doesn't like to idle when cold. I remember guys tuning LS motors used to drill small holes in the throttle plate to allow some air flow when throttle closed to help with idle.

Not sure what solutions to pursue from here. I'm tempted to try a learning ECU, how many standards are there for the harness plug (i.e is it likely a different mfg ECU will connect with my harness).

All thoughts appreciated.

Tom
 

Terry Oxandale

Skinny Man
I would think that the existing ECU could be flashed for improved idle mixture/rpm mapped to temperature.

In my case, I used a learning ECU, It was a huge learning experience for me (no pun intended), but the cold start idle is not an issue today, even with 8-stack injection.
 
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