95 lt1
i have no injector pulse what so ever. 12 volt side is solid. so far i have checked the restiance on the opti harness and have none. i have spark at the plugs, just no fuel. i have also replaced the ICM and coil. i was looking at the low res signal of the MSD opti . i noticed i am getting between 1 to 3 volts max. should i actually be hitting 5 or just in the range of 0-5? i have checked all the pcm grounds. i can spray gas into the intake and it will fire, then die when it runs out of fumes. could the MSD be bad out of the box, on the low res side? anyone else had this issue with a new msd or other opti?

ps. i also have a low impedance injectors and driver box. i have made sure the wires are not crossed and even bypassed the box.

 

I believe the level has to be 4 to 6 volts. Be sure you have a full 5 going to the opti on the red wire.

 

yeah i have the 12 volt signal on the red going to it. the 5 volts on the other 2 and then 0 on the pink and black. if it is supposed to be between 4 to 6 i am coming up short. any other ideas off the top of your head? oh yeah i disabled vats also

 

yeah I said 5 but it's 12 going to it. Are you throwing a DTC16? Call MSD and talk to the tech line to find out what the low res is allowed to be. But like I said, it should be 4 to 6 according to the shop manual for GM.

I would also check for injector pulses with all the injectors disconnected. Since you have low impedance units.

 

yeah i used a test light looking for the pulse on the connectors. i even looked for the signal before the wires go into the injector driver. i pulled the msd off last night to check the cam dowel pin and its engagement. all of it looked good, so i put it back on to try again. this time around i had fuel and no spark. i called summit and they are sending another unit. later today i am going to open the opti harness, from the ecm, and check the female ends and make sure they are not collapsed. as far as codes i am not seeing any codes at all. kind of weird. thanks for the advice so far speedy, keep those ideas coming. i need all the help i can get on this.