The wiring aspect of any LS swap is undoubtedly the hardest. Most builders are familiar with manufacturing techniques, troubleshooting, and replacing parts to make things work, but the electronics reach a much higher level of complexity. The wiring carried an air of mystery that sent shivers down the back of even the most seasoned builder, making him long for a simple carburetor and manifold. If you belong to this group, do not lose hope. In this chapter, you'll find the answers you're looking for, along with easy-to-understand instructions for LV switch wiring troubleshooting.
This tech tip is taken from the entire book,LS SWAPS: HOW TO SWAP GM LS ENGINES ALMOST ANYTHING. A comprehensive guide on this topic can be found at this link:
READ MORE ABOUT THIS BOOK HERE
SHARE THIS ARTICLE:You can share this article on Facebook, forums or any club you join. You can copy and paste this link to share:https://lsenginediy.com/ls-swaps-wiring-harness-and-wiring-guide/
Upgrading a standard wiring harness requires knowledge of electrical circuits, soldering skills and attention to detail. It's not a simple plug-and-play process, so make sure you're up to the task before breaking the wiring.
Gen III/IV engines feature complex computers that control everything from valve timing and ignition to fuel and air intake. On many LS engines, even the throttle is controlled by a computer; the pedal is connected to a sensor box that tells the throttle how much to open it. These systems can be overwhelming, but the key is to deal with them circuit by circuit. While factory systems are certainly top notch, the aftermarket has fully embraced the LS platform and there is definitely more than one way to get it right.
Wiring basics
If you picked up the engine from a junkyard or other used vehicle, you will need all the electrical components that came with it. I repeat: it is absolutely necessary to get everything. This includes the computer, wiring harness, mass air flow (MAF) sensor, oxygen sensors and, if the engine is electrically controlled, the accelerator and throttle control (TAC) module. Each engine requires the use of its own specific computer and wiring harness. Please note that changes are made to each system from year to year. To reuse as many factory components as possible, get them all together with the engine. It can be difficult to match key components such as the TAC module to the ECM without all the vehicle/engine details such as year, make and model.
The standard strap can be used as a substitute, or it can be put on a "thread diet" by cutting the loom and removing unnecessary threads. This is a great way to familiarize yourself with motor wiring. However, following each thread can be a headache.
Whether you use a stock or stock belt, the cleaner the installation, the better. This painless PowerBraid design protects wires from scratches and heat while maintaining a standard appearance.
Friction tape at the ends holds the braid. Regular electrical tape will work, but make sure it's a good quality material like 3M Super 33. Cheap stuff is rubbish.
Each Painless Performance kit includes all the necessary components: terminal block, relays and cable ties. You often need more terminals than are provided, so make sure you have plenty of different terminals handy. You can order bulk terminals directly from Painless.
Here is the complete assembly of the LS1 wiring harness. It takes some time, but the results are worth it.
Upgrading a standard wiring harness can seem complicated and possibly overwhelming. Actually, it's not that difficult at all. With proper diagrams and instructions, it can be modified to greatly simplify the motor wiring process. Most of the wires in the standard wiring harness are not needed for retrofits. Seriously, which 1969 Camaro needs evaporator tank coil control? However, there are different opinions on what should be removed from the standard wiring harness.
Classic Corvette wiring
Rat's nest, spaghetti, copper conjunctivitis; Call it what you will, but wiring is the most terrifying aspect of any car project. Whether you're chasing Gremlins via a 50-year-old survivor or swapping wires in a muscle car, most gearboxes just don't like wiring. But it doesn't have to be that way because there are tricks and tips that can turn a nightmare into a job well done. And you don't even need an electrical engineering degree.
There are two main types of wiring projects: repair or replacement of an existing system. For cables older than 40 years, a full replacement is often the best solution, especially if the car has already been stripped.
The Red Dirt Rodz crew provided all the wiring details for the 1967 Corvette roadster. This car, like many others, arrived at the dealership completely disassembled, as if the failed example was being sold from one to another. Although the original wiring harness was still there, most of the connections were broken, the wires were cracked and corroded, so it just wasn't worth fixing, especially since the car was completely restored. It's always nice to start over. One call to Painless Performance and the strap was on its way.
They managed to order a factory replacement wiring harness, which is already broken and is in the box just like the factory wiring harness, and everything is where it should be with stock components. But that wouldn't work for this project because the roadster has the LS1, electronic transmission, aftermarket gauges and all the new stuff you'd find on a new car. This situation required a new plan with new routes for this complex cabling system.
Wiring tools are critical. Using unnecessary clamps and dull knives does not make it any easier. The main tool for wiring work are clamps. Clamp connections are often notorious for incorrect installation. A well-made bend is as good as a solder joint. The wrench consists of properly selected tips and high-quality clamps. These cheap combination bending and edgebanding tools are no good; throw them away. They are only suitable for emergency repairs. You need a set of good terminals designed for insulated terminals. Klein Tools and KD Tools are excellent balers.
The first step is to disassemble the wiring harness and separate the groups of wires.
Plan your seat belt placement before you get to your car.
It is very important to install the wire clamps correctly. A high-speed striper really speeds up the process and is a worthwhile investment.
High-quality presses are the key to good stamping. This pair works great for insulated connections like the ones used on this car. They also work for non-insulated terminals.
Select the appropriately sized wire connector and insert it into the appropriate set of tool jaws. Using the wrong jaws can result in over-tightening (resulting in broken connection) or under-tightening (resulting in loose connection).
A properly placed clamp should look like this. The insulation is slightly bulged, but not crushed. Always pull on the cord and connector to make sure they are not loose.
Then find where the wiring harness on the engine side goes through the firewall. In the Corvette, we used a warehouse location. Be careful because sometimes the selected hole has a different function.
The fuse box is attached to the firewall with two screws. It can be difficult to install the fuse box; having a helper relieves a lot of frustration here.
The size of the metal support plate is adapted to the interior of the firewall.
Inside the car, the wiring harnesses are grouped and routed to their locations. Do not cut the wire until the entire wire harness is laid.
It is a push-to-start Painless Phantom Key system that includes keyless entry. This system replaces the ignition push button and includes all relays mounted under the center console in the Corvette.
The neutral safety switch and auxiliary light wires were routed to the transmission and terminated with spade terminals. This makes the removal of the shift lever no cuts required. You may not need to remove it, but it will be easier if you do.
All main ignition wires are gauge 12. They power most of the electrical system. The key to safe wiring is to use wire with the correct cross-section for the amperage. The longer the wire, the larger the diameter should be.
There are two main power cords terminating in a large power cord connected to the battery. Complete this with a large 12mm cable connector. The two wires on one side are smaller than the main wire.
Most Painless kits are not equipped with grounding. This is usually not a problem, but in the case of the Corvette, finding good terrain can be difficult. Use ground harness for rear lights; use the lug terminals and 14mm diameter lead wire to ground each lamp.
This tech tip is taken from the entire book,LS SWAPS: HOW TO SWAP GM LS ENGINES ALMOST ANYTHING. A comprehensive guide on this topic can be found at this link:
READ MORE ABOUT THIS BOOK HERE
SHARE THIS ARTICLE:You can share this article on Facebook, forums or any club you join. You can copy and paste this link to share:https://lsenginediy.com/ls-swaps-wiring-harness-and-wiring-guide/
The key to good grounding is a solid connection. The paint must be removed from the metal surface of the substrate. If you can't remove the paint, a star washer is an alternative as it cuts into the metal as you tighten the screw.
Then attach the ground cable to the frame using the fuel pump mounting point as a ground point. Using the same screw reduces the number of holes in the case and keeps everything neat and clean.
Then run a bunch of ground wires to each light. The rear lights are grounded to the mounting bolt. When using quick-locking nuts, be careful not to overtighten them or they may come loose.
Under the hood, separate each group of wires as in the car. There are quite a few small groups of threads here, so it's important to approach each one individually.
As each group of wires is placed on the motor, the wire harness will begin to connect. Keeping each group of vertebrae together can be tricky, so be patient. The hardest part of wiring is the planning.
Choosing the correct wire size for your terminal is critical. Using too large a terminal will result in a poor connection. Most terminals are color coded for size. Red is the smallest suitable wire with a diameter of 22 to 18; blue is for thread size 16 to 14, and yellow is for thread size 12 to 10. Anything larger is sold by size, not color.
The primary wire is typically 18mm diameter and is the most common wire in wiring harnesses. Larger high-voltage power cables are typically 14 to 12 mm in diameter.
The wire in Painless Performance kits is slightly larger than standard; main wires are 16 gauge and for heavy items like headlights they are 12 gauge.
Opening a box and seeing several thousand feet of wire can be intimidating. Do not be afraid. Is not so bad; be patient. The first step is to take everything out of the box and lay it on the couch or floor. Separate all bundles. Painless kits are pre-packaged in all major groups: motor, panel and rear. From there, they are divided into subcategories.
Another component used in Gen III/IV cabling is the Weather Pack and Metri-Pack terminal. These are small pins that require special bending tools. They are used in every connector on newer engine models. Most builders don't have to deal with disassembling and reassembling the calipers, but if you upgrade the stock wiring harness it will.
The MetriPack or Weather Pack terminal components are Molex housing or nylon silicone wire gasket and connectors. The housings have a specific shape; you need to make sure you have the correct male and female components. Terminals can sometimes be case-specific.
These are the terminals used for connections. They are available in many configurations and most of them have latches for full tightening.
The terminals must be crimped twice, once on the bare wire and once on the silicone insulation. Be sure to run the wire through the silicone sleeve before crimping.
Each terminal style has different pin types. All models lock into the plug housing using latches built into the terminal itself. Unlocking them can be difficult; The trick is to unlock it with a small toothpick or an unfolded paper clip. Each terminal uses a different lock location.
The DLC or OBDII port is essential with any LS replacement and is often overlooked when retrofitting a standard wiring harness. Be sure to take the wiring harness from the donor car. If you don't, you'll have to go back to stock or take a chance on eBay. (Photo courtesy of Street & Performance)
They are suitable for a typical project, but there may be some wires that need to be moved to another section. Now it's time to run all the wires again. Once you get in the car, the situation becomes much more difficult. Check each wire and its position and inspect the car. For example, if you are installing an electric fuel pump under the hood, you will need to reroute this wire as it is usually located at the rear.
All trouble-free wiring kits only feed the power side of the circuit. Except in a few situations, secure all ground connections. While this is usually a straightforward affair, the Corvette requires a bit of extra care as fiberglass is not a good substrate. Painless Performance has put a lot of thought into this and offers a grounding kit that includes a wire and terminal blocks to give you more grounding circuits where you need them.
Wiring the entire car takes planning, time and a lot of patience. If you feel frustrated with any particular part, get up and walk away for a while. A novice builder should be able to complete a simple wiring harness replacement in three to four days. The more circuits and complications like EFI, audio systems, etc., the longer it takes. However, if you take the time to plan the location of all the wires before cutting them, your wiring project will look and work great.
Extra straps
All information about connectors and relays (pages 87-91) shows what you can do with the LS1 harness. Designations for later models are on pages 81–82, however, each computer and engine has different operating requirements. This is complicated by drive-by-wire motors and on-demand positive displacement motors.
An off-the-shelf retrofit harness is generally the best solution for any Gen III/IV replacement. As a result, all responsibility rests with the technicians who have tested each belt and made sure it is correct. A simple crossover cable can mess up a standard PC and render it useless. In addition, purchasing an additional wiring harness also gives you the luxury of access to technical support for troubleshooting. If you have problems with an aftermarket belt, simply call tech support to get it running, saving you valuable time and money and potentially damaging your computer.
In modern drivetrains, everything is electronic, so proper earthing of the transmission is important. A simple braided ground strap to the frame will suffice. This also helps reduce electrolysis in the cooling system. (Photo courtesy of Street & Performance)
The body must also be grounded. Scrape the paint off the metal at the ground point or use a star washer to ensure a firm contact. (Photo courtesy of Street & Performance)
Some LS wiring harnesses have a fuse box under the engine. Paste it in a convenient place. If you are using a replacement wiring harness without a fuse box, make sure the power wires are secured. (Photo courtesy of Street & Performance)
A grommet is required when routing cables through the body. This protects the wiring from rubbing against the body, creating grounding and the possibility of fire.
These wires are standard ignition connectors for most GM cars. The large purple wires connect the relay to the starter motor. This is the quickest way to connect your vehicle's ignition switch to your LS starter.
The plug-and-play nature of Companion Armor, coupled with its relative affordability, makes it the best option and overall looks better than standard Hack Armor. Another thing to consider is that many factory belts are quite old. Over the years, the wires become brittle and corroded. The aftermarket wiring harness is brand new, so the replacement extends the life of the wiring. It is also impossible to tell if the computer and wiring harness has been carefully removed or pulled out, which can damage the wiring and connectors.
This tech tip is taken from the entire book,LS SWAPS: HOW TO SWAP GM LS ENGINES ALMOST ANYTHING. A comprehensive guide on this topic can be found at this link:
READ MORE ABOUT THIS BOOK HERE
SHARE THIS ARTICLE:You can share this article on Facebook, forums or any club you join. You can copy and paste this link to share:https://lsenginediy.com/ls-swaps-wiring-harness-and-wiring-guide/
Order a belt
Most stock strips are similar in their connections; they are separated by finer finishes and overall appearance. Many strips after sale remain in free form, that is, without a loom and wire wrap. Some wires, e.g. fuel injector wiring harnesses, are grouped together due to their location in the engine, but more on that later. It's up to you to cover the strip to give it the finishing touch.
Some aftermarket wiring harnesses group each set of wires together as if they were in the engine, and finish the job with wire or tape, making it easy to install right out of the box. If any part of the stock is replaced or moved to another location, the belt may need to be replaced. So please keep this in mind before ordering.
To ensure you get the correct replacement belt, there are a few things to consider before ordering. First, identify the engine and computer, whether it is an automatic or manual transmission, and whether the transmission is electronically controlled.
Old style automatics like the TH350 and manuals like the Muncie M22 are not electronically controlled, but the 4L60E automatic is electronically controlled. This is important because it requires connection to a computer. The MAF sensor has three or five pins (obtain this information from the donor vehicle).
It is also important to determine whether the throttle body is cable or wire operated.
The fuel injector type is the last piece of component information you need. There are three types: the old STD injector (which has a large metal clip), the T-type injector (which uses a Delphi 45 plug), and the Flex Fuel injector (also known as the Z-type). The LS motors are plug-and-play which makes wiring harness installation very easy.
Libra
After connecting the motor, there are still those annoying little extras like gauges that need to be connected. Since the original vehicles relied heavily on a computer system, all gauges were computer controlled. While this is fine for the 1999 Corvette, most older muscle cars require significant modification to retrofit computerized gauges from the latest model.
Each drive-by-wire motor requires its own pedal, throttle body, and possibly a TAC module. This is the LS2 kit for the GTO. The small box in the lower right corner is the Transmission Control Module (TCM). (Photo courtesy of Street & Performance)
Most companion harnesses are plug-and-play: just plug them in, plug in four wires, and theoretically start the engine. However, before you order, make sure you know the specifications of your engine and transmission as there are many options. The loose wiring harness allows all wires to be routed to components that may have been moved.
There are three types of fuel injectors. Shown from left: flex-fuel Z-pillar, old STD and Delphi 45 T-pillar. The flex-fuel engines are Z-style and the other two were used in different years, makes and models. (Photo courtesy of Street & Performance)
Even the throttle bodies are threaded. The throttle position sensor and MAF sensor must be connected. The MAF sensor is mounted directly in front of the throttle body. It can be moved using elbows and other components of the intake pipe. There are three types of MAF sensors: three-pin, five-pin and LS7 type. They cannot be replaced without changes to the ECM. (Photo courtesy of Street & Performance)
Throttle by cable is most compatible with older gearboxes as brackets for kickdown or TV cables already exist. (Photo courtesy of Street & Performance)
A cable-operated speedometer does little if connected to the VSS wire; it is also not a standard 1965 tachometer. Special attention must be paid to transmit information from the engine to the driver.
Speedometer
Tachometers are simple gauges that measure engine revolutions per minute. Although they are not absolutely necessary, they are particularly helpful, especially in cars with manual transmissions. If you drive your car aggressively, you need to know how hard the engine is working.
Ignition coil packs for Gen III/IV engines are very good from the factory, so there is no need to replace them at all. Their failure rate is very low. It will be difficult to find a dealer who has seen faulty ignition coils. (Photo courtesy of Street & Performance)
An adapter is required to transfer the tachograph signal to the old standard tachometer. The signal is modulated at a different rate than a typical V-8 tachograph. The LS signal must be converted by the module to a standard signal. These modules are available from Dakota Digital. Their SGI-8 module converts the tachograph signal to different settings, e.g. 4 or 6 cylinders. The tachograph signal coming from LS1 represents a 4-cylinder signal. Therefore, the factory tachograph with 6 or 8 cylinders must use this module to read the correct signal and display the correct value.
Programmable tachometers such as AutoMeter or VDO do not require this module as they can be set to read the 4-cylinder tachometer signal.
Speedometer
In the case of an electronic transmission, the electronic speedometer may receive the VSS signal via the computer, or the aftermarket speedometer may receive the VSS signal directly. If a newer model transmission uses a standard cable drive speedometer, the transmission must be cable driven.
From left to right: K&N air filter, three-pin MAF, 90 degree elbow with three-pin MAF and five-pin MAF. (Photo courtesy of Street & Performance)
If you are using a carbureted LS engine with a newer electronic gearbox, you will need a gearbox controller. This TCI 4L60E/4L80E ECU provides precise control and robust shifting of electronic automatic transmissions.
In the case of OEM 4L60E and T56 gearboxes, this is not a major problem. Street & Performance offers replacement cable-actuated rear axles. Most aftermarket transmissions already have a cable start option.
Oil transport unit
The oil sending assembly must also be adjusted. The oil cooler bypass port on the oil pan, just above the oil filter, is the ideal location to install the oil pressure port on the sending unit. Depending on the specific engine you choose from three bypass connection options: drilled and threaded connection; hollow extension that can be drilled and cut; or domed top.
While not strictly part of the wiring, you will need such sensor adapters if you plan to use an engine monitor that is not connected to the ECM. From left to right: coolant temperature, block oil pressure, and oil bypass adapters. (Photo courtesy of Street & Performance)
The 1997–2004 Corvette engines have a factory drilled and tapped 1/4 inch pipe thread, and the 1998–2002 F-Body has an extension but is not drilled or threaded. The 2005 engines have a domed cover without a head. You can use any of them. If you want to drill and tap the port, simply drill and tap it to the thread size required for the oil sensor port. You can also use the 16mm threaded port behind the intake manifold with an adapter that converts to 1/8, 1/4, 3/8 or 1/2 inch NPT threads for the oil pressure sending module.
Wire ride
The drive-by-wire system is a potentially confusing part of wiring conversion. Each drive-by-wire engine requires a separate pedal, throttle body and, in some cases, a TAC module. In most cases, drive-by-wire components are not replaceable. The foot pedal, TAC, and throttle body must remain attached to the engine for the pedal to function properly. The only interchangeable components are the Vortec truck modules, but the computer programming also needs to be changed. There are different parts packages that vary from vehicle to vehicle.
1997–2004 Corvettes use a pedal and a separate TAC module to operate a separate throttle body. In 2005, General Motors switched to a ride-by-wire pedal that incorporated a TAC sensor in the pedal, requiring only the pedal and throttle body to be replaced. The same applies to the 2005–2006 GTO, which used a specific pedal-only GTO configuration. The Chevy SSR trucks use a special pedal-on-the-wire pedal with the TAC module. The Cadillac CTS-V used the TAC pedal and module until 2004, but did not switch to pedal until 2005 and later. The 2007 Trailblazer uses a pedal only and is unlike any other truck.
Vortec Powered Carts with Adjustable Pedals are not suitable and must be modified for use with conversion motors. These trucks use a cable-operated pedal mounted on a movable platform that adjusts to the driver's height. Of course, you can easily replace the throttle body or cable-actuated carburetor on one of these engines.
Truck pedals and TAC modules are very confusing; It seems that General Motors has done a lot of different things with trucks over the years. The Drive-by-Wire system first appeared on trucks in 1999, and there were many different pedals with and without TAC modules. That is why it is so important to remove all parts from the donor vehicle beforehand. If you haven't stepped on the gas pedal (not everyone thinks about stepping on the gas pedal when replacing an engine), you can buy one from any GM dealer, junkyard or even a few parts stores, but you have all the details you need for your particular engine and ECM.
Special vehicle: Volvote - Volvo with Corvette engine
Images courtesy of Doug Strickler
This Volvotte started out as the daily driver for Douglas' father Dale Strickler. For many years he was an avid Volvo enthusiast. When Dale died in 1999, the rest of the Strickler family decided to give Doug a 1989 Volvo 740 Turbo Wagon as a gift. Doug had worked at Volvo for years and started playing with the station wagon by customizing the standard four-cylinder turbo engine.
In the end, Doug couldn't get much more performance without spending a lot of extra money, so he decided to replace the power sources and install the LS1. Reliability, ease of use and a much larger aftermarket were part of his decision. Of course, the station wagon still bore the "turbo" labels, and Doug felt there was no reason to drop them. Construction was going on, and Doug certainly had his hands full.
The hardest part of the whole swap was fitting the LS1 into a Volvo chassis. Engine mounts are handcrafted along with a completely custom 1/8 inch sheet metal cross member.
The art of creating custom motor mounts is to hang the motor on the frame wherever you want. This can be done by lifting the engine on a jack and placing blocks under it to secure it. The lift carries most of the weight.
Another option is to use a plastic engine block from Pay-R. These lightweight, plastic motors are accurately sized and are the perfect way to securely mount motor mounts for custom installations.
The engine had to be dragged as far away from the fire wall as possible to allow space for the turbines to be released. The derailleur cross member is made in a similar way, using a 1/8-inch steel plate.
As a turbo enthusiast, Doug believed that if one is good, two is better, so he settled on a pair of Garret T4 60-finish turbos for the LS1. Doug did everything with the Volvo and Carolina Auto Masters tuned him.
Currently, Doug drives the car every day and consumes 30 mpg on the highway. Volvo develops 544 horsepower on the rear wheels and does not cause problems with driving. To service the turbines, an Aeromotive A1000 fuel pump feeds the 42-pound fuel injectors.
To solve the problems with the auxiliary drive, Doug built his own system. Part of the turbo support also serves as a support for the auxiliary drive. This substitution is as conventional as it gets; Very few spare parts were used and everything was custom made.
The T56 is mated to Ford's powerful 8.8 rear engine with 9-inch Strange axles with 32 splines, bearing belts and 4.10:1 gears. Doug says he likes the deep shifters because there's plenty of power to get the car going as fast as he wants and it allows him to shift gears a little less often. Volvote ran the quarter mile in 11 seconds. Not bad for an old grocer.
Written by Jefferson Bryant and published with permission from CarTechBooks
READ MORE ABOUT THIS BOOK!
If you liked this article, you'll like the whole book as well.