Previously had a 5.3 with term x which ran great-now have a 6,0 with 862 heads and ms3 cam ( same fuel system, same injectors and everything as before. Now I’m only getting a weak spark at cylinder 3 and 2.
Ive already triple checked the injector and coil wires as well as the coil grounds. Engine starts right up and runs rough before eventually stalling.
#7 led for cam is red-I’ve already tried another cam sensor with no change.
any ideas?
All I can think of is to try coils next but it sounds like a wiring issue somewhere.

 

Check your grounds for starters.

 

Done.

 

Try running it in batch fire and see if it goes away. If it runs normal in batch then you have cam sensor issues.

 

Verify power to problem coils. Compare to good coil. Look at coil trigger signal. You can use a meter however a scope is best to do this. Again, compare to good coil.

 

just checked and I’m getting power to coils and injectors are getting signal(checked via noid light).
I swapped coils from a good car and I’m getting spark now but it’s red which I’m assuming means it’s weak.
also still have the red led for cam.
I also checked the coil grounds for the millionth time.

 

I've seen a YT video of someone with similar issues, turned out to be a terminal pushed back out of the coil harness inline connector and making poor/intermittent spark on one cylinder.

 

I’ve got a new ac Delco cam sensor on the way and will have to go through the harness/connectors this weekend. Not sure what else to check.

 

Still having issues-engine starts right up but getting a red led for cam.
Lq4 sbe.
Tried 2 good cam sensors. Cam wiring is getting 12v+.
Each coil grounded to head. Harness ground at frame. Red harness wire to junction box-box and battery have 13v+.
Red/white wire to factory fuse box and has 12v.