Ls3 376/480 initial start up issue
Thread Starter
Registered User
Joined: Nov 2023
Posts: 3
Likes: 0
Ls3 376/480 initial start up issue Ok guys I'm having issues keeping the motor running after cranking stops. Once the key is in the "on/run" position the engine dies. I've read a lot of posts stating that the PCM needs to be wired to a 12 V Ignition switch feed (little pink wire). The question I have is, should this power feed only be live when cranking? Or should it be live when cranking and in the "on/run" position?? I currently have it wire in the latter scenario.
Thread Starter
Registered User
Joined: Nov 2023
Posts: 3
Likes: 0
I did alot of harness work prior to start up. (Shortening of many wires) Is there a good connector pin out diagram for this GM Performance harness, so I can confirm I repinned all of these connectors properly??
TECH Fanatic
Joined: Sep 2008
Posts: 1,645
Likes: 526
Separate 12 volt constant wire for the ECM and separate 12 volt wire to the ECM in start and run. Doesn't say what kind of car but if older and had a points you need to confirm the voltage in run. If it had HEI I would just use the HEI ignition wire for 12 volts in start and run to the ECM.
