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    Results 1 to 9 of 9
    1. #1
      Join Date
      Oct 2011
      Posts
      547

      LSA Intercooler Wiring

      Trying to wire the intercooler pump from my LSA. I have a PSI engine harness which has a (pink wire) for intercooler trigger itís a ground wire. PSI sent me the below pic on how to wire the relay but Iím still confused.

      The intercooler pump has a positive and negative wire.

      Is this correct?
      Pink ground trigger goes to 85
      Positive wire from intercooler goes to 30
      12v ignition source goes to 86
      Power wire from battery goes to 87(where do I get this from? Starter or alternator?)

      What do I do with ground wire coming out of intercooler pump? Does that tie together with pink ground wire that goes into position 30 on relay? Or am I connecting it to an actual ground on the frame?



      Also if I have a 12v ignition source why is another 12v battery wire needed? Is that just to power the relay?
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    2. #2
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,906
      Country Flag: United States
      I am a little confused but that wiring diagram is not using the pink wire from your ECM to trigger the pump. Not a big deal, just confusing. It will work fine. I embedded comments below.

      Quote Originally Posted by joeko23 View Post
      Trying to wire the intercooler pump from my LSA. I have a PSI engine harness which has a (pink wire) for intercooler trigger it’s a ground wire. PSI sent me the below pic on how to wire the relay but I’m still confused.

      The intercooler pump has a positive and negative wire.

      Is this correct?
      Pink ground trigger goes to 85
      No it is unused as near as I can tell. Switched ignition goes to to 85.

      Positive wire from intercooler goes to 30
      12v ignition source goes to 86
      Power wire from battery goes to 87(where do I get this from? Starter or alternator?)

      I would connect it to the starter since you refuse to have a battery junction. I have to say as an engineer I tend to shy away from this sort of form over function thinking. I always have a battery junction post under the hood on cars with trunk located batteries.

      What do I do with ground wire coming out of intercooler pump? Does that tie together with pink ground wire that goes into position 30 on relay? Or am I connecting it to an actual ground on the frame?

      Ground it to the frame.

      Also if I have a 12v ignition source why is another 12v battery wire needed? Is that just to power the relay?
      They are trying to avoid overloading the switched ignition circuit with the pump
      current. Make sure you fuse this connection.
      One other comment. It is highly unusual to use pink for a ground trigger. Please post the documentation you have that says the pink intercooler trigger is a ground trigger.

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    3. #3
      Join Date
      Aug 2004
      Location
      Red Deer, Alberta, Canada
      Posts
      1,330
      Country Flag: Canada
      Quote Originally Posted by joeko23 View Post
      Trying to wire the intercooler pump from my LSA. I have a PSI engine harness which has a (pink wire) for intercooler trigger it’s a ground wire. PSI sent me the below pic on how to wire the relay but I’m still confused.

      The intercooler pump has a positive and negative wire.

      Is this correct?
      Pink ground trigger goes to 85
      Positive wire from intercooler goes to 30
      12v ignition source goes to 86
      Power wire from battery goes to 87(where do I get this from? Starter or alternator?)

      What do I do with ground wire coming out of intercooler pump? Does that tie together with pink ground wire that goes into position 30 on relay? Or am I connecting it to an actual ground on the frame?

      Also if I have a 12v ignition source why is another 12v battery wire needed? Is that just to power the relay?
      All they are saying is that the ECM sends a ground signal to activate the relay to turn the pump on. Much like the electric fans on stock ecu setups.

      Ground the pump to the chassis.

      In regards to the 12v ignition source, my understanding why they do that is, without the key on power, the relay does not have the ability to turn on when the ground signal is sent. Hopefully that makes sense.
      Matt
      72 Chevelle 370ci LS Turbo. Speedtech equipped.
      Instagram: Cst_koon

    4. #4
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,906
      Country Flag: United States


      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    5. #5
      Join Date
      Oct 2011
      Posts
      547
      Name:  2C3AAA70-CA5F-4AB7-A388-0B53B6A526C9.jpg
Views: 101
Size:  364.6 KBHereís the documentation:

    6. #6
      Join Date
      Nov 2006
      Location
      Mountain Springs, Texas
      Posts
      3,906
      Country Flag: United States
      Quote Originally Posted by joeko23 View Post
      Name:  2C3AAA70-CA5F-4AB7-A388-0B53B6A526C9.jpg
Views: 101
Size:  364.6 KBHereís the documentation:
      There you go. Really poor choice of color imho. I have no idea why the ECM needs to control the pump. I just turn my on when the car is running.

      Anyway you could connect this to pin 85 of the relay instead of connecting it to ground if you like. The pump ground still needs to go to chassis ground.

      Hope this makes sense.

      Don
      1969 Camaro - LSA 6L90E AME sub/IRS
      1957 Buick Estate Wagon
      1959 El Camino - Ironworks frame
      1956 Cameo - full C5 suspension/drivetrain

    7. #7
      Join Date
      Jun 2020
      Location
      Denver
      Posts
      21
      You need to run heavy gauge wire to 87 with a jumper wire to 86, pink from PCM to 85, heavy gauge wire intercooler power to 30, and ground intercooler to chassis.

    8. #8
      Join Date
      Oct 2011
      Posts
      547
      Why do I need heavy gauge wire? The stock intercooler pump wiring is maybe 16 or 18awg. Also the intercooler pulls around 5amps. Stock zl1 has a micro relay with 10 amp fuse.

    9. #9
      Join Date
      Jun 2020
      Location
      Denver
      Posts
      21
      I thought I remembered my buddies 03 cobra had 8 or 10 ga wire suggested. Maybe because it had a bigger aftermarket pump for a huge tank in the trunk. Use whatever the pump requires and you think is right. I always use at least one wire size larger than a pigtail is.