The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain > LSx Swaps

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-11-2012, 12:26 PM   #1
thump16
Registered User
 
thump16's Avatar
 
Join Date: Jul 2005
Location: Valdosta GA
Posts: 708
power source

okay square body guys. What wires are you using from the truck's firewall to power the ECU and LSX harness. Pics would be cool too. I know that the purple wire from original starter harness goes to ls starter but i want to make sure I am doing everything right. Thanks in advance
thump16 is offline   Reply With Quote
Old 04-11-2012, 02:31 PM   #2
ls1nova71
Registered User
 
ls1nova71's Avatar
 
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,118
Re: power source

Use the big heavy gauge red wire that originally went to your HEI to power the ignition relay for your engine harness.
Posted via Mobile Device
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html

5.3 swap into my RUSTY '71 C10
http://ls1tech.com/forums/conversion...71-c-10-a.html
ls1nova71 is offline   Reply With Quote
Old 04-11-2012, 07:12 PM   #3
clinebarger
Senior Member
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
Re: power source

Red is battery power
Pink is ignition hot
clinebarger is offline   Reply With Quote
Old 04-11-2012, 09:04 PM   #4
ls1nova71
Registered User
 
ls1nova71's Avatar
 
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,118
Re: power source

Quote:
Originally Posted by clinebarger View Post
Red is battery power
Pink is ignition hot
That's generally true, but did they change sometime between '73 and '87? Because I pulled an HEI out of I think a '79, and got the power wire for it and it's definitley red. Ok my phone sucks and it looks pink in this pic, but it's red.
Attached Images
 
__________________
My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html

5.3 swap into my RUSTY '71 C10
http://ls1tech.com/forums/conversion...71-c-10-a.html
ls1nova71 is offline   Reply With Quote
Old 04-11-2012, 10:14 PM   #5
clinebarger
Senior Member
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
Re: power source

Quote:
Originally Posted by ls1nova71 View Post
That's generally true, but did they change sometime between '73 and '87? Because I pulled an HEI out of I think a '79, and got the power wire for it and it's definitley red. Ok my phone sucks and it looks pink in this pic, but it's red.
Im putting a LQ9 in a 77 C10, The HEI lead "was" pink kinda a dirty off white now. The B+ wires were A real light red. The colors on my 85 burb are still vibrant so Pink/Red are easy to spot. I generally go by the White terminal on the end of the HEI wire.

The wire you have looks red to me, Maybe someone replaced the wire on the 79. As far as I know all 75-86 large cap HEI power wires were pink. 73/74 still used points
clinebarger is offline   Reply With Quote
Old 04-20-2012, 06:01 PM   #6
mooseknuckles
Registered User
 
mooseknuckles's Avatar
 
Join Date: Sep 2009
Location: ottawa,canada
Posts: 4,550
Re: power source

Quote:
Originally Posted by clinebarger View Post
Im putting a LQ9 in a 77 C10, The HEI lead "was" pink kinda a dirty off white now. The B+ wires were A real light red. The colors on my 85 burb are still vibrant so Pink/Red are easy to spot. I generally go by the White terminal on the end of the HEI wire.

The wire you have looks red to me, Maybe someone replaced the wire on the 79. As far as I know all 75-86 large cap HEI power wires were pink. 73/74 still used points
mine has the pink wire that used to go to the HEI, this is a switched 12v constant right?
mooseknuckles is offline   Reply With Quote
Old 04-20-2012, 07:40 PM   #7
clinebarger
Senior Member
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
Re: power source

Quote:
Originally Posted by mooseknuckles View Post
mine has the pink wire that used to go to the HEI, this is a switched 12v constant right?
Yes.
clinebarger is offline   Reply With Quote
Old 04-20-2012, 08:14 PM   #8
Dustytrix
Registered User
 
Join Date: Jan 2012
Location: Petal,Ms.
Posts: 428
Re: power source

Glad yall asked that question, I will be starting in a few weeks. Ok does this pink wire go to the stud on the ecm?
Dustytrix is offline   Reply With Quote
Old 04-20-2012, 08:36 PM   #9
mooseknuckles
Registered User
 
mooseknuckles's Avatar
 
Join Date: Sep 2009
Location: ottawa,canada
Posts: 4,550
Re: power source

I doubt it.....mine will be connected to a brown wire from my psi harness....
mooseknuckles is offline   Reply With Quote
Old 04-20-2012, 08:59 PM   #10
clinebarger
Senior Member
 
Join Date: May 2009
Location: Fort Worth, TX
Posts: 6,370
Re: power source

Quote:
Originally Posted by Dustytrix View Post
Glad yall asked that question, I will be starting in a few weeks. Ok does this pink wire go to the stud on the ecm?
Please elaborate. There is not a stud on LS PCMs.
clinebarger is offline   Reply With Quote
Old 04-21-2012, 09:02 PM   #11
Dustytrix
Registered User
 
Join Date: Jan 2012
Location: Petal,Ms.
Posts: 428
Re: power source

Sorry I meant fuse box, I guess I read ecm to many times.
Dustytrix is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:48 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com