how can i make a stock wire harness a stand alone harness. I need to buy one but dont have 600 to spend on one thats done. What do i need to do.

 

eliminate all the wiring tha tyou don't need and add the correct wiring, very difficult if you don't do it every day. Speartech did mine and it was only 450 for the harness and the work looked good.

 

im with u i can use those funds in performance parts...

 

I gotta tell you........I reworked my stock 99 Z28 Camaro harness to fit my 57 chevy and spent less than $30..!! That was for some shrink tubing, fine wire solder, roll of copper wire and electrical tape. It was the first one I ever did and I am no electrician. With the info in the stickies in this forum and several hours of fitting, measuring, soldering and taping I finished mine and it works flawlessly. Plus I decided where to put my PCM with no restrictions on harness length. I too didn't have the big bucks to buy one already done, so I just did it myself. I believe most average mechanical and electrical minded people can do this job if they really want to spend the time....and it does take time..!!!
No knock on the guys who build and supply the great aftermarket stuff intended..!!! That is MHO...!!!

Good Luck with your decision..!! DK

 

Im in the middle of modifying my harness. Ive done alot of searching for good how to post on harnesses and havnt found alot of info
What stickys or posts did u use?
I was thinking of moving the wires for the down stream O2s to the Upstream O2s on the PCM connectors so i wouldnt have to lengthen the upstream O2 wires and the connectors/wire colors are the same. Just about everyones using a header that locates the O2 below the firewall and many factory harnesses had the O2s mounted in the manifolds.

 

Before puttin the ls1 in my rx7.. I had never done ANY wiring.

Its not hard.

It actually not any harder than setting up a carbed car. Just need to ground the right pins on the PCM, and then different pins need 12v constant and then 12v at ign on and start.. Need to tune out vats and then tap into the tach output to get a tach signal..

Thats all I can remember off my head and I may be forgetting a couple things but its pretty damn easy. I was WAYYYYY overthinking it, I thought car electronics were a lot more complicated than they really are.

 

Did you check out the info in the FAQ sticky? https://ls1tech.com/forums/conversio...swap-faqs.html

 

I tweaked mine myself.. if you think about it, Harnesses are pretty much Stand-alone.. all you do it power it, ground it, and hook up the proper gauges for the signals.

 

I thinking of doing mine I can solder very well. And installed my own auto start in my truck. I hope I can do it. Also I have alldata. Think I can do it?

 

I have and what I guess most of us chicken sheets are hoping for would be a article that shows step by step what needs to be removed (and how/why) added -how and why. theres alot of wires and its intimidating until youve done one. with pictues ect - you know a real write up that they would make a sticky. so many replies are like add power to all the pink- ground all the blacks and remove what you dont need- read the pinouts thats it your done! I have a fair idea about how to do it but its like trying to defuse a Bomb- BOOM - oops I cut the wrong wire - now your F%#*ed! I have to say for most of us to look at a pinout and understand what you need to remove then what just cut that wire off ? maybe it'd be easier to say Dont cut this and this wire. Its amazing how many how to mod this, cam that on LS1howto hasnt done a harness mod write up? how bout it Gurus?

 

I'm a mass communications major and I plan on doing a complete writeup on how to make your own harness from scratch using junkyard connectors.

The unfortunate part of this is that I'm quite a ways from actually having my conversion ready for its first start up, so I may try building an engine stand I could run the motor on by itself to prove the harness works. Still this is a several months down the road unfortunately.

 

Here is a writeup that I did..it's for my Camaro, but if you know what you are doing you can adapt it to your application..

https://ls1tech.com/forums/conversio...o-lt1-car.html

 

Great post.
i am in the same boat ,I really would like to get a harness from speartech or painless, Etc
but i just cant see spending the coin on it. so i am going to modify it myself.
my swap is from a 2004 gto w/t56 i think the most useful tool is the alldata website if you have the diagrams you can identify all the wires and and all the components ( fuel pump relay , starter relay, cooling fan realys) and the correct wires for Clustr/gauges.
i will start a new thread with that progress however if we keep this post going maybe some folks who have done their own harness will chime it .

 

Even the basic PCM Pinouts come in very handy if you know what you are looking at. Then once you get in there you can trace out the wires. It does help alot to have the Connector Pinouts to start with aswell..it makes life easier.

 

Subscribing. I'll also be making my harness.

 

i want to use a factory harness and a factory computer. but i want to tune the car with a laptop any one no how i can do this?

 

HPTuners or EFIlive will let you do that. LS1 edit will too, but it seems to have fallen out of favor, haven`t heard much about LS1Edit in a long time.

 

Ok, just wanted to make sure you had seen them. Its difficult to do a step by step and what needs to be removed article because every conversion is different. I have personally wired 3 LS swap cars and there were a ton of differences between them. In the A/C alone, they were completely different. My swap used a hybrid of the LS controls and the el camino controls to turn the compressor on and off. On my brothers car the LS controls were left completely in place just incase he decides to ever add A/C to the car. On my friends car all of the A/C wiring was removed. Same for the fan setups. Mine has 2 relays to fire both fans at full speed at the same time. My friends has single relay and single fan. My brothers uses 2 fans and 3 relays to trigger the high/low fans the way the f-body did. Heck even the power is supplied differently. I didn`t really have room for the truck fuse box and I didn`t get it so I used a v6 f-body box and re-wired the truck harness to fit it and power the engine, along with using some of the factory computer fuses inside of my car that used to power the new PCM. On my friends car I made the engine basically stand alone with all the power for it coming from the LSx truck fuse box. My brothers car is the opposite, his 1964 fuse box from the car was in sad shape so we used the truck underhood fusebox to run the motor, but also a bunch of functions in the car.

I had wanted to do a step by step write-up for it, but haven`t really had the time and I haven`t figured out how to put it together because all the conversions are so individualized. Heck when I did my El camino I didn`t even have actual wiring diagrams for the truck, I had a ohm meter to trace the wires out and a set of mostly complete pinouts for the PCM, then I looked at the f-body diagrams to figure out what that circuit did. Let me know if you have questions about any of the specific wires/circuits I can explain them all pretty well now.

 

what does this software go for? and can i also data log?

 

You can datalog with HPT and EFILive, I believe also with LS1Edit, but I can`t say 100% for edit, I don`t know much about it as it was popular before my time.

For pricing you would have to check their websites, or the sponsors here. I know Wait4meperformance sells EFILive and I`m not sure if HPT is sold by some of the sponsors or just direct through their website (I bought it direct through the website). HPT was right around $500 when I bought it a couple years ago and IIRC EFILive7 was a hundred or 2 more expensive at that time.