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Ls1 idle issues

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I have a ls1 vy Commodore it has a mild cam inlet and long tube extractors.and a mafless tune.i adjusted the idel using hp tunners software it was all good except some times it would stall when air con was on it has got worse now to the point when ever the cooling fans come on it stalls even in neutral. I've checked tps idel control solenoid and just put new crack angel sensor in and coils .does it need more timming in gear and if retard or advance

Thank u

Kind regards

Rob walker

To make more torque, while idling, you generally add timing (ignition advance). We usually retard the ignition from MBT to get the engine to idle.

Hi, Rob!

You'll want to log a few parameters to dial in your idle: Engine RPM, Idle Desired RPM, Idle Air Control Position, Idle Air Control Desired Position, Idle Desired Airflow, Idle Base Gear Airflow, Idle Base PN Airflow, and Idle Adapt (STIT).

Start the car and use the throttle pedal to "walk" it down to idle. If you can do this, open your scanner and log those PIDs. Let the car idle for some time so the values normalize. If the car needs more air, you will see a positive value in the Idle Adapt area. From here, you can add air to your Base Running Airflow in the Engine>Idle>Airflow tab. It helps a great deal to use the g/sec measurement.

If you can't get the car to idle, follow the TPS and IAC relearn procedures.


1. Make sure the throttle is completely closed (TPS showing 0 on the scanner).

2. With the key off and scanner disconnected, unplug your TPS and IAC.

3. Turn the key on, engine off for 30 seconds.

4. Turn the key off, plug in TPS and IAC.

5. Start the car.