Here's the basic setup.

402ci LS1
10.75:1
Texas Giant on a 113LSA
520RWHP/475RWTQ
th350 trans

The drivetrain is in my '91 GTA and runs a '98 LS1 PCM and harness. Its currently running an open loop speed density tune and has a FAST 90/90 setup with a 4" CAI pipe from the fender well to the motor.

The main issue is idle... it surges terribly and cold startup sucks. My tuner is great but we can't always get together and work on it so I'm trying to learn some stuff on my own as well. I'm using HP Tuners to tune it, I can realtime log my AFR from my wideband on my laptop (using the EGR wire and custom PID's)

Question... where should I start at with the cold start issues and the surging idle? The car basically will not cold start unless you use the throttle to fire it up and help it stay running. As for surging idle, its all over the place.

I've done searches and read alot about tuning idle but I'm not sure how much of it applies to me since I'm open loop speed density.

Can anyone help point me in the right direction?

THANKS!
-Jeremy

 

increase your base running airflow. also, i delay the friction airflow 200 camshaft revolutions in the lower temps.

 

First you have to make sure the TB is set so IAC counts are 30-45 at hot idle(seems like 98's like that count)Then you raise the idle airflow table,expecially cold side.Make sure you are idling at the set timing like 22-28 degree's too.

 

So I should get it running and warmed up, then loosen the TB screw until I achieve 30-45 IAC counts? Then go from there and play with the idle airflow table?