Ground the PCM
 

Went for my first start today with 5.3 swap homemade harness. Dead with no fuel pump kick on. I imagined the worst, did the harness myself with lt1swap instructions. Read on another sight to ground the pcm case. It fired right up

Re: Ground the PCM
 

Thanks for the insight.

Re: Ground the PCM
 

The PCM body doesn't need to be grounded......If it did, You're missing ground connection somewhere.

Re: Ground the PCM
 

I've never grounded the case of the PCM on my LS swaps. But I've never built a harness myself. Always purchased the PCM and harness from the same supplier.

Re: Ground the PCM
 

Now that I think of it, there were a few stray ground wires not accounted for, but grounding the case fixed it

Re: Ground the PCM
 

With a LS swap, the more grounds the merrier...

Re: Ground the PCM
 

I had to do the same thing on my swap about 300 miles into swap I had lot of run issuses turns out I never bolted the grounds to back of the head and they where touching hit a bump lost ground I felt like an idiot but never went back and ungrounded the pcm

Re: Ground the PCM
 

As said above Ls swaps love good clean grounds. Main ground cable from the battery I run the 00 gauge cable directly to the engine block. Then on each side of the engine block back to the frame. Similar size cable. I try to hide them. If you have any paint on the block make sure you sand down to good metal. Star lock washers help bite into the head bolt holes.

Re: Ground the PCM
 

think it masks the problem of a missing ground... more than likely, something that's needing ground is going through a path its not designed for...

if that's the case, your going to be creating problems thats going to be hard to trouble shoot over the web....