New 5.3 LM7 low on power

[70TWO NOVA]

Well I figured it out finally, the company I bought the harness from screwed up and put the wires in wrong in the main trans connector. Luckily I had a factory harness to compare to. The wires were put in 180 degrees backwards in the connector. I had to removed them all, turn the connector 180 and reinstall them. Everything seems to work fine now. I haven't gotten into 3rd or 4th gear yet but it seems to be shifting perfectly fine. Now all I have to do is figure this misfire out....

[Todd in vancouver]

Originally Posted by 70TWO NOVA

Well I figured it out finally, the company I bought the harness from screwed up and put the wires in wrong in the main trans connector. Luckily I had a factory harness to compare to. The wires were put in 180 degrees backwards in the connector. I had to removed them all, turn the connector 180 and reinstall them. Everything seems to work fine now. I haven't gotten into 3rd or 4th gear yet but it seems to be shifting perfectly fine. Now all I have to do is figure this misfire out....

Great news and glad you were able to figure it out. Make sure you post some burn out pics once you get it out

[tooblue]

Originally Posted by 70TWO NOVA

Well I figured it out finally, .

[70TWO NOVA]

So far on the misfire I have; verified good fuel pressure 58-60 psi, checked the plug wires and coil. Swapped the coil/plug wire and the misfire didnt follow the coil. I used a noid light to check the inctor circuits, removed the coil sub-harness and checked all the wires for continuity/resisance, pulled the valve cover and made sure the valves were opening properly, removed the plugs (#7 is clean and shows good continuity and isnt broken internally) I fired up the engine for a few seconds and touched each header and found that cylinder 7 is the only cold one. So far everything I have looked at checks out fine. The only things I havent done is verified good coil driver circuit for cylinder 7 or checked for a physical clog in the injector. Any other ideas??

[Z06vette]

If the motor sat for any length of time, that injector could be plugged. I could not get my LS1 to start after the swap. I checked everything & nothing was out of order. I couldnt figure it out. I pulled all the injectors and soaked them in sea foam overnight. Put them in & it fired right away. Have you checked that plug- is it wet with fuel? Bad plug possibly? Scott

[70TWO NOVA]

Well I went through the harness wires (power and signals to coil connector) all the connections and wires were good. Just to be sure I pulled the wires out of a GM harness that I had and ran them instead of the wires that came with the harness. Still no change, miss on cylinder 5. I switched the coil out with one I had and it seemed to not be misfiring as bad. Maybe both my coils are bad?? I dont know what the odds of that are but Im out of ideas at this point. I think Im going to check the injectors next. I know they did sit for a while, its possible they got clogged.

[70TWO NOVA]

After scratching my head over this for a while I finally figured it out I think. Since I pretty much ruled out an ignition problem I pulled the fuel rail and injectors last night. I found a few little pieces of what seemed to be silicone sealer (the orange stuff) in the inlet side of a few injectors. I cleaned them out, but the real issue was that the #5 injector wouldnt "click" at all when I applied power to it. I checked all 8 and that was the only one that didnt work. This makes perfect sense since #5 was the cylinder throwing the code (P0305). I ordered a new injector from Rock Auto last night. Hopefully it will come by Friday so I can verify that was the issue all along.

[Todd in vancouver]

How did you make out?