Conversions & Swaps LSX Engines in Non-LSX Vehicles
Sponsored by:
Sponsored by:

wiring issue/questions

Thread Tools
 
Search this Thread
 
Old Nov 13, 2017 | 07:04 PM
  #1  
bgbainbridge's Avatar
Thread Starter
Teching In
 
Joined: Jan 2016
Posts: 6
Likes: 0
Default wiring issue/questions

Short question: Is there any wiring that can't be cut and extended in the engine and trans wiring harness? What are the 3or4 small gauge wires that go into the ignition switch, can they be removed? -if not how can I hook them to a simple ignition system?

Long form of the same question:
Working on putting a lq4 into an old Cadillac. I was able to drive it around the block about a month ago at the time I had only cut out some wires from the original Express3500 harness that weren't needed (example radio harness, headlights....) After the drive I decided that I would mount the PCM and fuse box.
Now the car will turn over and cough, but won't stay running, (plenty of fuel pressure)
The 2 big changes that I can thing of are, extending a 12pin plug that runs from the ECM directly to the fuse box, not sure what they were but the were all copper ~18ga wires. The other variable was I wired in the Caddy's ignition. The van had a plain cut key and with the car turning over and coughing I assume that I don't have VATS, but there were 3 small gauge wires that go into the ignition that I didn't know what to do with, could this be my issue?

thanks for your time
Brad
Reply
Old Nov 13, 2017 | 07:45 PM
  #2  
JoeNova's Avatar
Restricted User
 
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
Default

Without knowing what wires you're talking about, its hard to say.
You can cut/extend any wire in the harness that you want. They are just wires, no magic there. The engine harness shouldn't have any wires that go into the ignition switch.
Reply
Old Nov 13, 2017 | 08:56 PM
  #3  
ls1nova71's Avatar
TECH Veteran
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (4)
 
Joined: Jan 2008
Posts: 4,406
Likes: 211
From: Liberty, MO
Default

Sounds like you're using the whole wiring harness out of the van? Column too? If so, the wires could be to the ignition switch could be your problem, because I'm pretty sure vans have VATS too.
Reply
Old Nov 13, 2017 | 09:04 PM
  #4  
G Atsma's Avatar
TECH Senior Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Default

I would bet any GM product from the last 20 years has VATS.
Reply
Old Nov 14, 2017 | 07:17 AM
  #5  
Old Geezer's Avatar
TECH Senior Member
iTrader: (3)
 
Joined: Jun 2004
Posts: 5,639
Likes: 71
From: GA, USA
Default

Spend a few $, download/print the wiring from Diyalldata.com.
Reply
Old Nov 14, 2017 | 08:20 PM
  #6  
bgbainbridge's Avatar
Thread Starter
Teching In
 
Joined: Jan 2016
Posts: 6
Likes: 0
Default

Thanks for the replies, I am using the harness from the van but didn't keep the column, just the ignition switch.
I will have to try and wire back in the ignition switch.

Here is a photo of the wires I wasn't sure about
Attached Thumbnails wiring issue/questions-20171114_185736.jpg  
Reply
Old Nov 14, 2017 | 11:18 PM
  #7  
green camaro's Avatar
Teching In
 
Joined: Aug 2017
Posts: 12
Likes: 0
Default

yes those are important and you need them matched to the VATS box. or get someone to unlock pcm for you. if the vats box and key are not correct to the pcm it will only have ign, for 1-2 seconds before killing signal.
Reply
Old Nov 16, 2017 | 08:51 PM
  #8  
bgbainbridge's Avatar
Thread Starter
Teching In
 
Joined: Jan 2016
Posts: 6
Likes: 0
Default

thanks again,I ran a jumper back to the ignition with it plugged into this little harness and seemed to do the trick.

I appreciate the help
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo




All times are GMT -5. The time now is 07:33 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE