Background: 2004 LQ4 from a Savannah 3500 cube van swapped into a 1951 Pontiac. Due to space constraints the ECM is located on the passenger side inner fender, while to new fuse/relay box is on the drivers side inner fender. The original harness is plenty long for this - I actually will be shortening and re-pinning about 50% of the wires. I've pulled all the excess wire to within a foot of the ECM and will redo each wire one at a time.

1. Is it ok to run all the pink +12v power wires in a separate loom side by side across the main wiring loom? There's no reason to keep any distance between them correct?

2. For the grounds - there is 7 heavier ground wires coming from the ecm to a heavy splicing that is grounded to the cylinder head. I have a several lighter gauge grounds from each side of the motor - can these all be combined to one grounding point, or do I need to ground to both cylinder heads (as originally wired). I am planning on running a heavy ground wire from this point back directly to the battery as well.

As always, any input is greatly appreciated!
Cheers
TM

 

1) There's no drawback to running them together like that. If you're concerned about RFI, then it's not a major problem for LS controllers in general

2) They're 18ga where most data lines are 20ga. Some lighter duty applications use 20ga for everything. As long as they're all properly grounded, it makes no difference
Additional grounds are never a bad thing

 

Thanks for confirming what I thought would be suitable. Best to ask and confirm before I get everything wrapped up and then later find about something I didn't know about !!!

Cheers