I have questions about wiring this sucker up.

[trapin]

Alright, I'm going to warn you all.....I am good at drivetrains, engine building, some fabrication and just about everything else involved in restoring cars (I even know a little about painting if you can believe it). However...the one area where I literally fall flat on my face is electrical, and I'm not afraid to admit it. I am so stupid when it comes to electrical and wiring stuff up it's not even funny.

So lets begin with a few questions that will be the first of many, many, many, many, many questions I will need to ask as I head into the home stretch of firing up this LS1. For the record, my PCM and Harness have already been sent out to be edited and tuned. I should be getting those back in a couple weeks. PCM is being done by Norris Motorsports, Harness is being done by Wait4meperformance.

My first question....where does the PCM draw it's power from? From the Starter? Somewhere on the engine? From the main fuse box? battery? Also...does the PCM need to talk to the ignition via a wire or does it do that through some other means?

I told you this was going to be bad.

......it's not too late to start running.

[LSx_88_Ciera]

It gets its power from the fuse box. Make sure that it has power in both run and crank.
There are no provisions for a comm link between the ign switch and ECM unless a pass key system is used which is not likely in your situation.
I have my thinking cap and running shoes on so I am ready one way or the other. :)

[dhutton]

It will need both switched (keyed) and unswitched power. I added a small fuse panel with relay made by Painless wiring. It goes directly to the battery and has a control line that connects to the "pink wire" in the column to control the relay for the switched power. Helps keep the power for your ECM etc nice and clean plus gives you the fuses you need for your fuel pump, ECM etc. I think this is the one I used:

http://www.summitracing.com/parts/PRF-70207/

[rockytopper]

I used the current performance fuse and relay stand alone unit. It has everything in it including fuel,a/c, and fan relays. it is pretty much plug and play. My ls1 swap is my first and frankly the wiring was the easiet part of the swap. I to am a metal head but there isn't much to it it you get the diagrams you need. http://www.currentperformance.com/Accessories/wiring_acc.html

[CarlC]

Tony, they should have a minimal number of connections for you to make. Ign +, +, -, fans, fuel pump, tach, etc. All very easy and should be labled.

As mentioned above there is a + to the battery. If you are considering using a battery shutoff switch to kill power to the vehicle I highly recommend that you have a small separate circuit to power directly to the battery to the + on the PCM. The GM PCM's have a learning function. The more you drive it, the more it learns and fine tunes. If power to the PCM is lost, so is this new data.

I have a small three-amp bypass that keeps the various memories in the car up when the main switch is thrown. However, every month or so I forget to turn the switch back on and then the breaker trips. I then get irritated as the car re-learns itself.

[LSx_88_Ciera]

I have a small three-amp bypass that keeps the various memories in the car up when the main switch is thrown. However, every month or so I forget to turn the switch back on and then the breaker trips. I then get irritated as the car re-learns itself.

Have you considered totally isolating the 3A bypass to where both + & - come straight off the battery this should prevent the breaker from tripping due to the closed loop of the 3a circuit.

[trapin]

God I wish I knew what you guys were talking about.

This exercise should get easier when I get the harness back and then I can post pictures of problem areas for you to help me with. I hope you guys are right in that a lot of it will seem obvious.

[camcojb]

God I wish I knew what you guys were talking about.

This exercise should get easier when I get the harness back and then I can post pictures of problem areas for you to help me with. I hope you guys are right in that a lot of it will seem obvious.
it will be obvious Tony. :)

Jody

[Bow Tie 67]

Tony,

Your PCM is the Brain, the wire harness is the arteries, your battery is the heart ( blood supply ).

The harness should be labeled and be very easy to hook-up. Don't overthink things.

All that will be needed is battery positive, battery negative ( or good ground ) and switched ignition power.

Switched ignition power is when your ignition key is in the on position. These wires are generally always Pink. ( power is only hot when the key is on )

Battery positive is hot / live all the time regardless of ignition switch position. This is also referred to B+ or hot battery bus.

I hope that helps, and is a little more laymens terms.



Feel free to contact me, I have been through this and am currently up on it. The last 6 weeks I have been messing with my vehicle and engine harness.

Matt

[CarlC]

Have you considered totally isolating the 3A bypass to where both + & - come straight off the battery this should prevent the breaker from tripping due to the closed loop of the 3a circuit.

That's what my recommendation is. A separate circuit to feed the + PCM that bypasses the main on/off switch. A negative feed off the battery is not needed in a negative ground based system.

[LSx_88_Ciera]

That's what my recommendation is. A separate circuit to feed the + PCM that bypasses the main on/off switch. A negative feed off the battery is not needed in a negative ground based system.

I know that a direct ground is not needed I was referring to your situation of the breaker tripping when you forget to close the battery disconnect.
But to be honest I don't see how turning the key on would trip the breaker of the 3a bypass you mentioned since there is no potential at the ignition switch when the disconnect is open.
The only thing that would make sense would be if you have 2 circuits feeding the memory circuits, one from the main harness and the bypass. If that is the case what is the point since they are tied together in the end giving a flow path to the main harness unless you use an inline diode.

Sorry just doesn't make sense and there has to be some sort of additional path to items other than the memory circuits if the breaker trips when the disconnect is open.

[trapin]

OK...and we're back.

My PCM and Wiring Harness are now back in my possession. Many thanks to Mike Norris and Norris Motorsports for the PCM and Wait4meperformance for the wiring harness. Here are a few pics of the areas of the harness I will need help with. It appears I am going to have to finish these aspects of the harness myself and I guess a first question would be...when lengthening any of these lines, does it matter what kind of wire is used? I notice some different colors and not sure what gauge or material is required based on the color of the wire. Or does it not matter? Thanks

Also, can you recommend a good soldering gun? Thanks again.

https://static1.pt-content.com/images/pt/2010/04/4536286737_3f272d5952-1.jpg

https://static1.pt-content.com/images/pt/2010/04/4536283161_59e5ff05a4-1.jpg

https://static1.pt-content.com/images/pt/2010/04/4536281289_4ba528f11f-1.jpg

https://static1.pt-content.com/images/pt/2010/04/4536913178_5013b09706-1.jpg

https://static1.pt-content.com/images/pt/2010/04/4536911538_0d4e23e6a4-1.jpg

[dhutton]

For the O2 sensors you can buy C5 rear sensors that come with long cables that will reach no problem. You can also buy O2 sensor extension harnesses.

In that second pic the terminal goes to the starter solenoid and the other two plug into the appropriate sensors down by the starter. One is the crank sensor, the other one looks like the oil level sensor but I can't remember 100%. Either way they should be the right length to just plug in.

For the other ones if you match the gauge of the wire in the harness (bigger is OK too) you should be fine.

Don

[trapin]

Thanks Don. I am going to have to try and find the part numbers for the C5 sensors and maybe the extensions.

I'm also going to have to check to see that my AutoKraft pan has the sensors in it. I seem to remember that my factory pan had sensors in it where the AutoKraft didn't have the provisions.

[CarlC]

You don't need the pan oil level sensor. The ECM does not use the signal for anything.

Do you have plugs that will fit your current O2 sensors? It's not hard to extend these.

To extend the wires use a splicing wire that is the same gauge as the parent. Use a crimp connector to join the ends, and if you want, solder then together. Use heat shrink to insulate each splice. Soldering alone does not make for a good splice. Solder is not as good a conductor as copper wire, hence a splice where the surfaces of the two wires are clamped together is best.

A Weller soldering iron will serve your needs nicely. I don't like guns since their size limits accessibility.

[dhutton]

Thanks Don. I am going to have to try and find the part numbers for the C5 sensors and maybe the extensions.

I'm also going to have to check to see that my AutoKraft pan has the sensors in it. I seem to remember that my factory pan had sensors in it where the AutoKraft didn't have the provisions.

If you use C5 sensors you don't need the extensions. It is one or the other. The extensions are aftermarket parts.

[parsonsj]

I've switched over to a butane soldering iron. It gets hotter faster, and no cord is required. As Carl said, always make a secure connection with wire and splice device, and then use solder if you want. Solder will eventually fail when it is the connection.

jp

[ErikLS2]

FWIW, most if not all OEM harness splice points don't use solder. They are crimped and insulated properly and rarely fail. As has been said, soldering only will eventually fail and if it's crimped properly with the right tools solder isn't needed in the first place.

[trapin]

What splicing crimps do you guys use? You're not talking about the plastic encased ones that they sell at the hardware store are you?

[parsonsj]

I cut the outer plastic off of those, and use them with a "pegged" crimp, followed by at least one layer of heat shrink tubing. I often use two or more layers of heat shrink to give a more professional/OEM look.

jp

[6'9"Witha69]

I cut the outer plastic off of those, and use them with a "pegged" crimp, followed by at least one layer of heat shrink tubing. I often use two or more layers of heat shrink to give a more professional/OEM look.

jp
+1, I also bought some packages of non insulated crimp crimp connectors pretty cheap from a local electronics store. Heat shrink too. I have rolls and sections of the stuff in various sizes. Much better and professional looking than insulated butt connectors.

[CarlC]

+2.

One day I'll try to track down the expanding foam sealant types that are used in LS engine harnesses. They are really nice, corrosion resistant, but are a bit bulky.

[trapin]

Thanks guys.

More to follow.......

[Bow Tie 67]

I've switched over to a butane soldering iron. It gets hotter faster, and no cord is required. As Carl said, always make a secure connection with wire and splice device, and then use solder if you want. Solder will eventually fail when it is the connection.

jp

When extending wires, and there are several in one area, I like to solder and heat shrink to reduce the bundle size. My method: strip back both wires enough to twist them together axially then solder and heat shrink.

[dhutton]

When extending wires, and there are several in one area, I like to solder and heat shrink to reduce the bundle size. My method: strip back both wires enough to twist them together axially then solder and heat shrink.

I like to use the "Western Union" splice when connecting wires followed by solder and heat shrink. I've seen too many poorly crimped splices fail, mostly due to the wrong technique and/or crimping tool.

http://www.tpub.com/content/neets/14176/css/14176_46.htm

Don

[Bow Tie 67]

I like to use the "Western Union" splice when connecting wires followed by solder and heat shrink. I've seen too many poorly crimped splices fail, mostly due to the wrong technique and/or crimping tool.

http://www.tpub.com/content/neets/14176/css/14176_46.htm

Don

Thats it, I did not realize it had a name. Learn something new every day.

[6'9"Witha69]

Thats it, I did not realize it had a name. Learn something new every day.
x2.

[trapin]

Nice.

Do you guys have a source for the crimps that you use?

[6'9"Witha69]

www.mcmastercarr.com

or your local electronics shop

[parsonsj]

I like to use the "Western Union" splice when connecting wires followed by solder and heat shrink. I've seen too many poorly crimped splices fail, mostly due to the wrong technique and/or crimping tool.Nice link! I've seen similar methods and used them a time or two as well. The key to this method is to strip enough wire for a secure connection before soldering.

jp

[CarlC]

Agreed. I use that type of splice as well. However, note that Western Union type of splice has a very high percentage of wire contact. A simple in-line helix twist does not have sufficient wire contact and is not mechanically sound.