nitrousc5

This is the first time I''ve ever had a problem after opening a motor where I cannot get a spark. I just replaced the head gaskets on my 389 LS6 stroker in my 2001 C5. All back together, everything plugged in, fluid in, etc. Engine only cranks and there is fuel, but no spark. Wont fire. I have triple checked all connections and fuses. No codes. I never had the cam or crank sensor unplugged. However, in the course of the repair there were times when the harnesses had some strain on them as I would manuver them out of the way. Also, I steam cleaned the motor at the half way point. I did make some effort to ensure all sensor connectors were dry and clean. I would think if i had a bad connection that I would get some code. Or, have I cooked the PCM somehow? If anyone has experienced these symptoms, please chime in. thanks.

2xLS1

iTrader: (25)

F-bodies have ground wire lugs that bolt to the back of the heads that if are not connected, will cause that. Not sure about vettes, bit it's something to check.

Bink

Vettes are the same - left head/bank.

Hey Robert!
joel

nitrousc5

These lugs on the back of the driver head was one of the first things I double checked yesterday. I was able to see the one lug with the two black w/white stripe ground wires for the coil packs. While it is nearly impossible to get a wrench on the 15mm bolt without taking intake off, I did feel by hand that it was tight + i made sure during reassembly to put these on (I have caused these symptoms before by leaving this ground lug off). Anyway, I racked my brain for a very long time on this problem. I was measuring some 15k ohms on each coil pack ground wire. I finally pulled the intake off again to triple check the ground connection on back of head. Visual showed it to be ok. However, I started pulling back the harness insulation to find BOTH wires nearly ripped in two as if the wires were smashed or stretched real hard. About two strands of braid held one together, the other completely pinched. WTF?? made the repair, all good now. I couldnt tell you how these wires got in this condition INSIDE the harness. Thanks anyway for your suggestions. Much appreciated.

1point3liter

I believe there are three wires going to each coil. It has been awhile, but I'm pretty sure.

One is a 12v source
One is a Constant ground
One is a ground trigger from the PCM

Take a multimeter and make sure they are getting power. The pink wire on the connector should be getting constant 12v is my memory serves me correctly. I would imagine the key has to be on to see power, but my ls1 is in a rx7 I'm not sure how you're cars are.

Also check the ground as other's have mentioned. There's another connector that goes into the harness that supplys power to the coils. I'm not sure where this is on your car ( I cut it out of my harness and rewired it) but if you unhooked it that could be another possibility.