HEY GUYSI DID AN ENGINE SWAP ON AN 03 TAHOE BUT IT DOES NOT START I GET NO INJECTOR PULSE FROM IT IM THINKING ITS THE SECURITY THAT IS LOCKING ME OUT DOES ANYONE KNO IF THERE IS SOME SORT OF PROCEDURE OR ANYTHING THAT MIGHT HELP

 

well u could've left some grounds undone. or connectors. wat happens when u turn ur key on? we need a few more details.

 

turn key on evrything lights up on dash turns off like normal ignition stays on when the key is on no security light but as soon as i crank it to try to start it security light comes on and then turns of i trippled check all my connectors ground evrything that i could think of i hear the fuel pump cutting on i have spark just no injector pulse

 

[ol]Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON; the vehicle will not start.
Observe the SECURITY telltale; after approximately 10minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5seconds.
Repeat steps 1 through 4 two more times for a total of 3cycles/30minutes; the vehicle is now ready to relearn the Passlock Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK.

Important
The vehicle learns the Passlock Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.

Start the engine. The vehicle has now learned the Passlock Sensor Data Code and/or password.
With a scan tool, clear any DTCs, if needed. History DTCs will self clear after 100ignition cycles[/ol]
try this hopefully it works for u.