Complete your LS replacement with an independent wiring harness (2023)

For the LS motor replacement series, we can't skip wiring! Your '69s Camaro, '70s Chevelle, and even your '90s Firebird are not tuned to the LS engine, so you'll need a wiring harness to make it all work. Fortunately for you, this is not as difficult an obstacle to overcome as it might seem. In fact, starting this LS can be an easy task.

What are my options for using the LS engine?

You have two options to start the LS: or you get oneindependent baror customize with aCARBURETOR. I icarburetor.This is a really cool idea, and if you want to know more about it, we have an article for you.

But let's say you stick with fuel injection. In some cases, a standard wiring harness can be fitted, but this requires more than just basic wiring knowledge. Second option? Professionally designed, self-contained plug and play wiring harness.

What is a standalone bar?

You might be wondering what the hell independence means. The independent beam is used only to control the motor, i.e. the base. Compared to the factory harness, the stand-alone harness is slightly smaller and has fewer connections. It is not intended that there will be many additional options such as cruise control or fuel management.

Also, while some standalone devices only have four connectors for starting the engine (e.g. one for battery, ground, ignition and fuel pump), you will need to make other connections to the computer, registering data sensors and so on.

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Complete your LS replacement with an independent wiring harness (1)

So they are as simple as they appearcapable ofbut in nature it can be quite complicated. Either way, with basic knowledge and a measurable amount of patience, we're confident you'll be able to handle the installation.

What should I do if I want/need these additional options?

If you are in a smog situation that requires pollution control, or if you are trading in an LS for a vehicle that needs/want these extra options, don't worry. You can always buy a factory custom harness designed for riding the LS. Please note that the make and model will determine which manufacturer is required for this purpose.

If you are in a state like California, the law requires you to transfer the donor vehicle's emission options. Even though you are getting into a vehicle that is 30, 40 or even 50 years old, you still need to add all the emission sensors and components, including the MAF and EVAP sensors. You might be wondering if a standalone bar is a possible option. While it is possible to add these additional controls to the system after initial installation, many manufacturers will simply remove the factory wiring harness from the donor vehicle and transfer it to the replacement vehicle to avoid the hassle of customizing the aftermarket system.

Watch the video below to learn what to consider in this situation.

(Video) ĹS Wiring For Dummies, Easiest Stand Alone Harness Installed - 1957 Chevy First Start In Years!

Complete your LS replacement with an independent wiring harness (2)

Buy the right stuff

The vast majority of LS aftermarket parts use a standalone belt because it is simple and inexpensive. Sure, you can build your own system, but considering a standalone Painless Performance system, e.gTenfor the GEN III LS engines it costs around $600 retail, you really can't beat that. Please note that not all LS motors are created equal, so it is very important to do your research and purchase the correct wiring harness.

Painless Performance is a great source for standalone belts as they offer them for the LS Gen III and Gen IV engines. All you have to do isspecify the generation of the engine you are working with, select the correct part number and get ready to assemble.

Complete your LS replacement with an independent wiring harness (3)

Each belt is a painless performancecontrolled qualitybefore leaving the building to make sure all circuits are working. In addition, all kits include easy-to-follow instructions and color-coded, labeled wiring for easy installation. Most Painless harnesses come in a standard four-foot length, which is ideal for builders looking to mount components under the dash or in the glove box. For those wishing to mount under the seat or on the center console, 2.5m harnesses are also available. However, please note that Painless cannot predict how routing will be performed in every vehicle. This means you have to do your homework.

Plan, plan, plan...

No matter how "simple" the installation is, plan enough trial assemblies and take the time to mimic the various components to eliminate errors and redundant work. To be honest, installing a wiring harness can be tricky because the wires have to go through the firewall.

(Video) Wire harness instructions

Inside the vehicle, find a place to mount the PCM and fuse box, making sure there is enough slack in the wiring to route the electronic wiring of the gauges, if used. Beyond the firewall, you need to make sure that all connections can work properly without limiting each other's range or putting yourself at risk of contact with hot or moving parts. And let's not forget that all this must be done in such a way that it looks nice.

Complete your LS replacement with an independent wiring harness (4)

In short, LS is LS; so connecting the wiring harness to the engine and sensors is not a problem. However, there are some restrictions on the location of the fuse box, PCM and O2 sensors in the vehicle. This requires extra finesse and planning. The last thing you want to run into after running your cabling through your firewall is not having a good place to mount your components.

Sometimes it will turn out that there is no good "factory" assembly site, regardless of planning. In these cases, custom O2 sensor mounts and/or extensions are often the solution.

Wiring made easy

Once a game plan is developed, these systems basically become plug-and-play. However, wiring can be a problem as it keeps sticking. So work slowly and keep order. Take the time to straighten out the wiring harness, find the most attractive/safest way to route the wires, and get to work. As far as where to start, the best way to hold the wiring harness down is to start with the coil pack and injection connectors while working on all the other connections.

(Video) How to make an LS Engine Stand Alone - L96 With an E78 ECU

Complete your LS replacement with an independent wiring harness (5)

There is no racing and keeping a relaxed attitude is simply a way to achieve a show quality schedule for your belt. Many people find it intuitive to know which connector is connected where. But even if you're a complete layman, most providers are kind enough to identify each connection with identification tags. Turn on music orgood car podcastTry not to think about the claustrophobic environment you work in and act.

Working in such a tight space, it's easy to damage the cord.Check out our series on the basics of repairing the electrical system in a carto make sure everything goes well.

Take PCM

Remember: you still need a custom PCM to run this LS. If you do not pay attention to the PCM module, despite the correct wiring, nothing will happen when you turn it on for the first time. Of course, this can be extremely frustrating.

Often this problem is due to the fact that factory VAT has never been excluded. Unfortunately, professional help is almost always needed to get it right, but there are some very good resources available for programming and fine-tuning the PCM for LS swapping. I definitely recommend giving it as a giftLT1swap.comtake a photo when the time comes or if you just want to know more about the process.

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