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- - LS Engine Wiring (https://67-72chevytrucks.com/vboard/showthread.php?t=660798)

LS Engine Wiring

Guys I could use a sanity check on my engine wiring. Wiring up an 07 LQ4 using a PSI standalone and Speedway 12 circuit harnesses.

• PSI harness connect to the same terminal as the battery on the back of the starter
• PSI harness connects to the 4-pin plug on the alternator
• PSI harness connects to the ignition switch (On) – power during on and cranking
• Body harness connects to the battery on the back of the starter via the fused link.
• Body harness provides connection between ignition switch (start) to the NSS then to the starter
• Need a wire from the lug on the back of the alternator to the battery terminal on the starter
• In the body harness the following connections are not required: alt power, alt exciter, coil, choke

Questions:
• What is alt power in the body harness used for? Isn’t the harness getting power from the battery/starter terminal?
• Using a universal ignition switch – the IGN or ON has power during on and cranking?
• In the body harness the “ignition switch ign” brown wire does what?

http://psiconversion.com/tech_articl...structions.pdf
http://static.speedwaymotors.com/pdf/910-64017.pdf

I think that’s it for now. Thank you in advance.

Re: LS Engine Wiring

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Sometimes the weekends are a little slow on here. I don't have enough experience to help you out on this but someone will chime in.

LockDoc

Re: LS Engine Wiring

Henney,
I'm in Milwaukie Oregon and I have my wiring all done on my swap, if you want to come up and take and look at my setup. I did not use a PSI harness it is one from BP Automotive but they are all similar I think. I can't start it yet but can help with wiring. Shoot me a PM if you want.

Rich

Re: LS Engine Wiring

Speedway has a great harness. Did you read the directions. The direction we're very detailed for the install. If I were you, I would install you car/truck harness first. I can't trouble shoot your troubles now, cause I need to the direction. Pm me your number and I will call you direct. I'll help as much as I can. Clark.

Re: LS Engine Wiring

Quote:

Originally Posted by Henney (Post 7056396)

Questions:
• What is alt power in the body harness used for? Isn’t the harness getting power from the battery/starter terminal?
The alt power should be the power for the alternator. However, since the LS harness controls the alternator now, you shouldn't need it, you just need to make sure you have a wire to the battery from the big lug on the back of the alternator
• Using a universal ignition switch – the IGN or ON has power during on and cranking?
The IGN should stay hot while cranking, this is what you would power up the ignition relay of the LS harness with.
• In the body harness the “ignition switch ign” brown wire does what?
Assuming the harness is color coded after an older GM harness, which they almost always are, the brown wire would be the accessory power wire. This will power up all your accessories, like radio, windshield wipers, power windows, etc. Pretty much all the things that loose power when cranking the starter.

Hope this helps.

Re: LS Engine Wiring

Thanks for the input guys.

LS that was exactly what I was looking for.