I pulled the entire engine/trans harness without cutting or breaking a single plug from a 2003 1500 series Chevy truck. I also snagged the computer and the under hood/fender liner mounted wiring junction box.

What will I need to do in order to make the wiring function in an older car which is running a new wiring harness through but it is carbed. Is there a way to just plug all of the wiring back into the junction block/computer and power it as it is without having to strip down the harness?(looks are not of a concern right now) Will the alternator charge? Will I need to run new ignition to starter/wiring? Does absolutely everything function through the computer?

I am not familiar with the computers in these either, will it run without special tuning or changes?

I did not grab any of the interior wiring going to the dash/cluster/interior, will this be an issue?

Im trying to do this on a budget but if you guys tell me to pay someone who knows what to do to dumb down the harness to make easier or if there are tricks and such please share.

 

http://www.thirdgen.org/techboard/po...009-post4.html
http://www.thirdgen.org/techboard/lt...-question.html
http://www.lt1swap.com/wiringharness.htm

At minimum you'll have to identify the proper wires in the body connectors to be cut free and assigned to salvaged portions of your swap car's wiring for gauges, fuel pump, fuses, ign etc. This is much easier by stripping the harness and building it to suit. It take a very long time, but in the end looks better and is much simpler to troubleshoot

Alt will charge using the new PCM. Read this if you dont want the PCM to control it
https://ls1tech.com/forums/conversio...aq-thread.html

Any PCM you use will require atleast basic tuning to disable VATS

Missing dash wiring is of no consequence

You can DIY, lots of info out there in both the minimal effort method and complete rebuild. Choose whats best for you and give it a try

 

There are a couple color hints too. Pink, key on power. Orange, always hot.

read up, there are lots of things to learn.

 

i used the lt1 swap website to build my harness. tons of info on the site and they walk you through how to build your own harness, they give you all the pin charts and tell you what you will and wont need. i kept the stock f.i on my harness. you will just have to do some research on what you will be able to eliminate because your running the carb. my harness took me about 8 hours to build. if you have the F.I why not use it? wont be alot of work to keep if your ripping into the harness anyway and would save you tons of time on the harness, you wont have to remove half the wires from it. if you dont have the FI you can pick them up cheap. IMO putting old technology on a new school motor isnt worth it.

 

I am keeping the fuel injection, I currently run a carbed sbc and th350. Im also using the 4l60e trans and wiring from the 2wd truck I pulled the whole setup out of.

 

ok good stuff, must have misread your post.

 

I think he meant that the old engine was carbed.

 

thanks for the clearup ls1.. good luck with this build. im doin a 5.3 w/ turbo 12 lbs boost w/th350. hope it all comes together as planned

 

I did mine with the info from lt1 swap and bought a new fuse block from current performance wiring has everything you need for wiring rebuild.