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 02-18-2013, 11:57 PM   #1
themb2g
Registered User
 
Join Date: Jul 2010
Location: Portland, Oregon
Posts: 411
LSX questions

I have a 1972 Blazer and a 6.0 lq4. We are putting the wiring harness together and i have a cuople of questions.

1. Can we eliminate the oil pressure wire to the PCM and use the old hard line straight to the gauge cluster, or will it mess up the computer somehow? Same question for water temp.

2. We have a one wire alternator from a vintage air front runner system. Do we need to run the alternator to the PCM or can we just bypass the PCM and run direct to the gauge?

3. Has anyone else used the Vintage Air Front runner on here for an Lq4? The alternator looks like it has a plug port, but there is a cap that wont come off.

Thanks!

MB
__________________
Check out my build: 1972 LQ4 Swap

http://67-72chevytrucks.com/vboard/s...=1#post5427693
themb2g is offline   Reply With Quote
Old 02-19-2013, 01:26 AM   #2
71chevystep4x4
Registered User
 
71chevystep4x4's Avatar
 
Join Date: Sep 2012
Location: Milwaukie OR
Posts: 135
Re: LSX questions

As far as the oil pressure goes, you can just remove the pins and wires from the PCM plug and run the hardline to the cluster. Keep the temp hooked up because the pcm needs to know the temps the engine is running. Not sure about the alternator, I was wandering that myself. So far, mines not hooked up to the pcm, and everything seems to be working fine.
71chevystep4x4 is offline   Reply With Quote
Old 02-19-2013, 03:51 AM   #3
ls1nova71
Registered User
 
ls1nova71's Avatar
 
Join Date: Dec 2009
Location: Independence Mo
Posts: 4,118
Re: LSX questions

As stated, you don't need the oil pressure sender. I usually break the plastic part of it off and drill and tap the aluminum base to accept the fitting for the line.

On the alternator, if it's.a 1 wire alternator then it's self exciting and nothing needs to be hooked up. That plug is where the wires would plug into a regular alternator but there isn't anything to hook up on a one wire so they put that plug in them.
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 02-20-2013, 02:16 AM   #4
BR3W CITY
meowMEOWmeowMEOW
 
BR3W CITY's Avatar
 
Join Date: Sep 2009
Location: MKE WI
Posts: 7,128
Re: LSX questions

Just to add, all the oil pressure wire does is tell the pcm that there is oil pressure...thats really it...and the pcm doesn't care what the answer is. I think its just used to trigger the idiot light if there is a complete loss of oil pressure. Some late model cars and trucks can get an oil pressure reading through the pcm, but these trucks do not.
__________________
'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING

MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD
BR3W CITY 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 09:07 AM.


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