You need to tune off the VATS. I also had the emissions stuff tuned off. Using a factory 2002 Harness and ECU. The ECU has 160 pins on it.
MAF (3 wire)Intake air temp (2 Wire)MAP (2 wire)TPS (2 wire)CTS (1 or w wires)Oil pressure Sended (1 wire)Oil Level (2 wires)Bank 1 o2 sensors (4 wires each)Alt (2wires)If your using a T56 you need 2 wires for VSS
Then 16 Injector wires, and the coil pack wiring (32 wires) (all factory GM harness stuff)
The ECU will also look for the high and low fans, I use the low fan on signal only (high tuned off), AC clutch fan relay, Fuel level relay,
Then MIL lamp to the cluster. You can use the Nissan gauges to work (Speed, Tach, oil, water)
Good links
http://www.ls1tech.com/forums/....html http://ls1tech.com/forums/conv....html
But yea, find a mail tune place. Tell them you want the VATS (Vehicle anti-theft system) off, Then have then edit some of the basic factory stuff.
This is my initial mail tune that got it running.
2001 - 2003 LS1 Operating System Installed - Eliminate VATS (vehicle anti-theft system) - Rear O2 Sensors Delete- Fan 1 Temperature On - Fan 2 Temperature Removed- 3.689 Axle ratio- Tire Size Changed- Top MPH Raised- 6800RPM- Diagnostic Trouble Codes Delete- A/C Deleted- EGR Deleted- Air Pump Deleted- Fuel Tank Pressure Sensors Delete- Disable Torque Management (automatic)- Eliminate Skip Shift (manual