LS no start Help

[paul mora]

Just completed by second LS conversion. Using a PSI harness for the first time. I got the entire package from a friend of a friend who I trust. Went to start it for the first time and it cranks fine got power everywhere but when I crank it I get a fluctuating voltage to the coils and other power systems. I gone over the wiring diagram and lit all seems right. Could the relays for the ignition and fuel pump send a signal that causes the voltage to shut down. The battery is strong and it show over twelve volts till I start cranking. I see the same voltage fluctuations. I have several ground to body frame etc. Any ideas where to start troubleshooting

[kglowacky]

how long has this engine not run. my first swap Mine would not start. Called programmer he said when an engine sits awhile the injectors get stuck. I tapped on all the injectors with the end of a screwdriver and it fired right up. Your assuming it is in the spark side but it may be the fuel side. o you have fuel pressure? NOTE I am a poor mechanic so take this advice for what it is worth. Good Luck keep us posted

[mongocanfly]

Like kgl says...could be injectors or fuel pressure.....I know the psi harness has grounds but what about your other grounds?...battery to engine, engine to frame, engine to body, body to frame....cant have to many on a LS

[paul mora]

I am up and running. There is a ground wire that connects to the head on the backside of the motor. I overlooked it and after a review of the harness drawing I saw it and we are up and running. Thanks for the input everyone

[kglowacky]

great news now start enjoying it.

[bigmoe]

That'll be a relief you got it started. Man there's nothing like that feeling when it fires up! Glad it was something simple that you could figure out. Now get it on the road!

[mongocanfly]

Good deal...