hey i jsut finished most of the wiring on my 3rd gen swap to a 96 LT1 and i am using a obd1 PCM. I dont think my pcm is sending any signal or getting any power? the fuel pump wont prime but i can get it to work by jumping it. the engine turns over and everything but i am not getting any spark so i think its the pcm. How does the pcm get power and where does it ground? there should be a wire that sends a 12v constant or when the ign. is on to the pcm? i went over all the wiring a few times and i have one ground coming off the block by the distributor coil? is there any more grounds coming off the block?

 

The battery grounds on the block,there should be acouple grounds at the coil grounds to the coil stud.

 

Was VATS disabled in the PCM before you attempted to start it? That could be whats causing your problem if it wasn't, if its set up in the PCM like it is in the OBD2 LT1s. Engine swap cars without the 'chip key' and often even ones that DO have them, have to have VATS disabled before the PCM will let the engine fire.

 

Actually VATS won't cause the problem he's having, the motor will still fire and run for about 2 seconds before it runs out of fuel due to the VATS from keeping the fuel pump coming on.

There are two different power wires for the PCM (actually I think 3) 12v switched and 12v constant, then the ignition also has 12v switched as well. Sounds like the PCM isn't getting any power with the fuel pump not priming.

 

yea the vats was disabled along with a few other little things on the pcm. I think my pcm ground should already be connected since the wiring was already attatched to the motor correct? Its mostly likley those couple power wires it needs. I dont remember seeing these power wires on any of my harnasses? do you guys know which harnesses they are in or should i tap into them by the pcm??

 

nevermind guys. i ran those ignition wires found out one was only getting 1.5 volts for some reason and switched to another ign. wire and heard the fuel pump prime then turned it over and it fired rite up . not gonna be able to drive it til i get a few other things fixed but its getting close to completion. Thanks alot for you guys help tho.