Electrical wiring harness?

Picture of mine with the red loom and his without.

I don't see the other image. Can you please reupload it? If it is the main power feed wire then yes this is the problem.

Here is the picture of the other truck.

Any broken wires are not good and can cause no power, it is still difficult to see what you are talking about. Does the truck have power when you open the door and do the dome lights come on?

Sorry, the wires are two baby blue, one green, one white, and one black that are cut I think one is the chsml and maybe SGW

Maybe a better picture to see driver's side.

The red wiring cover is not factory, If the truck has no power is the battery in good shape? If so, let's check the main fuses.

Here is a guide to help and please check out the diagrams below:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

With the key on do you have power at these fuses? Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

Yes, there's power at the fuse box and power at the smaller junction box I'm leaning towards trailer/tow signals. The truck it's self has terrible response and engine power which is because of the misfire on cylinder 4 and 8, tons of oil in the cylinder heads and little metal dust particles, just going to pull the motor and do a tear down and rebuild for the customer, the wires in his truck have obviously been missing for some time because they're all cut the same length not like they've been ripped out, so I don't think its coinciding with his power loss...

I've got the same exact truck just with 4wd compared to his 2wd and I rebuilt my motor exactly like the rebuild of the 5.3 y'all have on YouTube.

Nice the engine looks good; I will pass this onto Ryan our engine builder to see if he has anything to add.

The only thing I can add is check your rocker arm to valve cover clearance. That might be your little metal particle problem.

When we first built the engine, I thought the normal height ones would work. But when I bolted them on there was like 1 thousandth of interference. The engine would turn over and seem fine. But when we ran it on the dyno there was a tiny amount of clattering, and it turned out that our rocker arms were just barely tapping the valve covers. That sent small bits of metal into the pan but luckily the oil filter did its job, and the engine was fine after an oil change, fresh filter and taller valve covers. These are the taller version https://www.summitracing.com/parts/sum-440362 if you used roller rockers like I did. But if you used the stamped steel rockers you are totally fine with the stock height covers!

So, if you did use roller rockers and the stock height pan that would explain a bit of metal in the oil. You might not need to tear it all apart.

I updated the link in the description about a year ago, but I cannot change the part number in the video.

Thanks so much for watching and for using 2CarPros!

Best,
Ryan

There are two different trucks the one I'm working on for a customer and the motor that is going in my truck but they are both 2006 Silverado 1500 5.3s and I did follow your videos on you tube but I used Texas speed and performance parts and my rocker arms are the gold comp cams with all arp studs and long tubes with true dual Flomaster exhaust with an xoipe, rebuilt front and rear end and all new guts in the transmission with a Corvette servo also still trying to decide what programmer leaning towards the diablo... as for the other truck we decided to donate rebuild on that one also.

To do a rebuild not donate a rebuild, sorry.

Oh, I see now. I misunderstood what you had meant. Your engine is a super cool build by the way!

Let me know how your client's build ends up and where those mystery wires lead to!

Best,
Ryan

Will do, I'll keep you posted thanks for the quick replies.