Each engine requires its own computer, and the programming must match the engine, so computers can’t be swapped even if the plugs are the same type. General Motors produces several computer types and each is built for a specific engine group. Some work with many engines, and some only work with one. It is very important to obtain the original computer, harness, and sensors when buying a used engine. This ensures that you have everything needed to make the swap as simple as possible.
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Of course, if you are buying a crate engine or can’t get all the original components, the aftermarket will come to your rescue. They offer engine management systems for both EFI and carbureted engines (carbureted LS engines are available from Chevrolet Performance as crate or carb-converted Gen III/IV engines). The possibilities are almost endless.
Later ECMs for 1999–2002 LS1s look different and are different than those for a 1997–1998. The wires are in different places, so an early harness cannot be wired to a later ECM; it simply doesn’t work. (Photo Courtesy Street & Performance)
It has been said before, but it bears repeating: The ECM can’t be changed to operate a different reluctor wheel. The reluctor wheel setup can be changed, but it requires the corresponding computer. Gray sensors are 58x, and black sensors are 24x. (Photo Courtesy Street & Performance)
There are two main types of computers: 24-tooth and 58-tooth reluctor wheel engines. The reluctor wheel is mounted to the crankshaft inside the block to the rear. The crank position sensor is mounted to the rear of the block, behind the starter. As the crankshaft rotates, the teeth on the reluctor wheel interrupt the magnetic field created by the sensor.
The sensor records these interruptions and sends a signal to the computer. These signals are used to detect issues, such as misfires and detonation, with the ignition system.
Reluctor Types
It is important to know which reluctor type you have, 24x or 58x. You can tell by looking at the reluctor wheel sensor: a black sensor is a 24x wheel, a gray sensor is for a 58x engine.
The following engines came with a 24-tooth reluctor wheel:
- 1997–2004 Corvette, LS1 or LS6 (all were drive-by-wire)
- 2005 LS2 Corvette
- 1998–2002 Camaro/Firebird
- 2004 LS1 GTO
- 2005–2006 LS2 GTO, 2004–2006 SSR (LS2 and 5.3 liter)
- 1999–2006 4.8-, 5.3-, and 6.0-liter Vortec truck engines
The 1997–1998 LS1 Y- and F-Body computer is different from the later LS1 ECM. The pin-outs and wiring harnesses are different. This is a 1998 Camaro ECM, front and back side. (Photo Courtesy Street & Performance)
This is a 58x reluctor computer; the ancillary parts are very expensive, so make sure to get all of them from the donor car. Otherwise, you will spend a lot of money to buy these components individually. (Photo Courtesy Street & Performance)
Changing the reluctor wheel also requires changing the cam timing gear. The reluctor wheel and the cam gear work in tandem to monitor the ignition system. If they don’t match, the engine doesn’t run. (Photo Courtesy Street & Performance)
There are several different drive-bywire pedals. Shown from left to right: a 2005–up Corvette, 2005–2006 SSR, 2005–2006 GTO, and Lokar pedal replacement pad. Not shown are pedals for the 1997–2004 Corvette, CTS-V, 2007 Trailblazer, and the rest of the trucks, which interchanged through the years. (Photo Courtesy Street & Performance)
The pedals and TAC modules are a matched set. You need both units to properly operate a drive-by-wire throttle. (Photo Courtesy Street & Performance)
These throttle bodies are: 1997–2004 Corvette (top left), Vortec trucks (top right), drive-by-wire assembly (bottom left), and LS2 2005 GTO (bottom right). (Photo Courtesy Street & Performance)
Engines can be drive-by-cable or drive-by-wire, depending on the vehicle. The 58-tooth reluctor wheel is found on drive-by-wire engines only. This reluctor wheel cannot be used with a drive-by-cable throttle body without modifications. If you want to run these engines with a traditional throttle cable, they need to be converted to a 24-tooth reluctor wheel, along with a 2005 cam gear on the front of the engine and a 24-tooth reluctor wheel computer.
The following engines have the 58-tooth reluctor:
- 2006–up Corvette LS7
- 2008–up Corvette LS3
- 2007-up 4.8, 5.3, and 6.0 Vortec truck engines
Each engine uses a specific computer. The wiring harnesses are dedicated to each computer, so it’s very important to get all of the components when pulling an engine from a salvage vehicle. If you do not have the proper computer, you can find a wide range of used LS computers from various retailers.
ECM Programming
The 24x ECMs can be programmed for either drive-by-cable or drive-by-wire. For instance, a 1999 F-Body LS1 with a drive-by-cable throttle body can be wired to a 2000 Corvette drive-by-wire ECM, but the ECM must be reprogrammed to reflect the drive-by-cable change.
You can also convert an engine to drive-by-wire by reprogramming the original computer for drive-by-wire, but you must be able to plug the wiring harness into the particular computer. The 1998 F-Body computers and harnesses are not compatible with 1999-up harnesses or computers because the plugs are different. If you plan on running the stock harness and computer, make sure to get them from the donor vehicle, or buy used if you can’t.
Programming the stock ECM can be done several ways. Home-based programs, such as HP Tuners and EFI Live, are designed to work with the Gen III/IV computers. Most of the aftermarket tuning modules and software are locked, meaning they lock themselves to a particular computer on the first use. To unlock them, you must purchase pass codes or VINs for additional vehicles. Some products include two passes to tune two separate vehicles. When purchasing tuning software, you typically have unlimited tuning capability (or “tunes”) on the same vehicle.
ECM Tuning Packages
Do-it-yourself tuning packages are very efficient and handy to have. They allow you to tune the engine for a multitude of parameters, help identify trouble codes, and add some personalization to the engine with-out getting greasy. But there are some things that home-based tuning software can’t do. Most software packages can’t make significant changes to the programming of an ECM, so you can tune the engine, but you cannot change the ECM from drive-by-wire to drive-by-cable or vice versa.
Tuning an aftermarket ECM is easy with supplied software. Some are simple programs using predetermined options, and some are full-blown custom tuning packages that allow you to control every aspect of the tune.
The software also is not the best way to swap a computer from a different year to a different engine; this requires more significant programming beyond what the tuning software was designed for. These programs are great for what they do: tune the existing programming to better suit your application and needs.
HP Tuners
This comprehensive tuning software allows you to fully tune and adjust a stock ECM. Available in a base or pro form, the HP VCM Suite adjusts Gen III/IV computers. HP works on the credit system and allows you to tune up to four specific vehicles or unlimited tunes for the same year and model vehicle (any 2000 Camaro LS1, for example), or even unlimited Gen III/IV vehicles.
Each option costs credits. A single vehicle license costs 2 credits per year, model licenses cost 6 credits, and unlimited LS1 tunes cost 70 credits. The basic software purchase includes 8 credits and additional credits are always available, adding to the flexibility of the software. This home-based software costs a good deal more than a handheld tuner or shipping your computer off, but it has much more flexibility and is likely worth the extra cost in the end.
However, the HP software cannot load programming from different model years to any given computer. Therefore, you need to start with the right-year computer for your engine application.
The HP VCM Tuner Suite comes with the handheld scanner required to upload the tunes to the vehicle, but does not come preloaded with tunes. The software gives you access to hundreds of tunes, and you can even build your own. The HP tuner software is also easy to upgrade to the most up-to-date information and calibrations.
EFI Live
EFI Live offers several versions of their products including FlashScan and FlashScan and Tune. The tuning version allows to you build your own ECM tunes, controlling all aspects of the ECM programming. The FlashScan software works on a VIN licensing system, which requires each vehicle to be licensed. The main kit includes two VIN licenses; additional licenses can be purchased.
The EFI Live software is capable of tuning Gen III and Gen IV computers. The FlashScan software features more than 600 engine calibrations for in-depth ECM tuning, as well as fixes for issues with stock computers such as VATS, MAF, and TCS (traction control system) fault codes. The software is constantly upgrading and evolving, ensuring the product you purchase not only serves its current purpose, but is up-to-date as the technology changes.
Handheld Tuners
These are an alternative to the home-based software programs and offer more portability for tuning the engine. Handheld engine tuners allow you to tune the computer on the fly and run diagnostics whenever the need strikes and regardless of location. Upper-end handheld tuners are typically comparable in price to the entry-level, home-based software programmers.
Handhelds usually control the basic functions and parameters needed to tune the engines, but only the basics; computer-based software programs have many more variables and options. The biggest advantage of the handheld tuners is their ease of use. The simple user interface makes tuning easier than the home-based software.
Reprogramming Services
If you need to change from drive-by-wire to a throttle cable or swap a newer ECM to an older engine, you need to work with a reprogrammer. Shops such as Street & Performance and Speartech offer reprogramming services to precisely program the ECM to your requirements. If you plan on just keeping a stock or slightly modified tune in the computer, having the stock ECM reconfigured is usually cheaper than buying a tuning package. It is also the only way to make certain changes.
For factory computers, HP Tuners software is the most complete of all of the aftermarket software available to consumers. It allows you to change just about all parameters of the ECM programming. (Photo Courtesy HP Tuners)
If you buy a used engine, the wiring harness, computers, and peripheral equipment are there for the taking. But if you buy a crate engine, this equipment may need to be purchased separately. This engine controller from Chevrolet Performance offers the best of both worlds: a factory-backed computer with performance tuning built in. (Photo Courtesy General Motors)
Other considerations also need to be addressed on some pull-out engines. Most vehicles built with Gen III/IV engines use the ECM to control automatic transmissions, but not all of them. The LS2 GTO uses a transmission control module (TCM) to send information to the PCM. Both of these components are necessary if you are going to use the stock computer. Vortec platforms began using the TCM module on all the automatic transmission trucks in 2005.
In addition, if you change the style of transmission, automatic to manual or vice versa, the tune should be changed in the computer.
If running an electronically controlled automatic such as a 4L60E, use the tuning software to enter the VIN (on the side of the case) into the ECM or TCM module so the computer has access to the transmission.
Transmission Controller
If you use an electronically controlled transmission without the stock computer, the engine management may not support the transmission. In this situation, you need a transmission controller. TCI’s Transmission Control Unit (TCU) and Painless Performance’s Perfect Torc offer greater tuning capability of the GM electronically controlled transmission than the factory controller. These units are compatible with most GM electronically controlled automatic transmissions. They provide load, gear, RPM, and speed-based programming with the click of a mouse.
The TCI unit is also fully compatible with CAN 2.0B engine management systems, such as the FAST XFI system, which makes it easy to integrate the TCU with the engine controller.
Chevrolet Performance offers a factory-tuned transmission controller for carbureted and aftermarket-EFI LS engines. This is essentially the same control found in factory ECMs. (Photo Courtesy General Motors)
Transmission controllers come with tuning software and wiring harnesses. The software allows you to change many parameters, even allowing paddle and push-button shifting configurations along with manifold-pressure-based shift firmness, greatly adding to the ability to tune the transmission far beyond the capabilities of a stock TCM or ECM.
Aftermarket Engine Management
Aftermarket engine management has many benefits that go far beyond the factory computer capabilities. Some builders say the stock computer is more than enough to control their LS engine, and they’re correct: the factory computer works very well for a stock engine. Simple tuning changes and adjustments are made fairly easily and quickly show improvements in performance. Even entry-level performance mods such as to the exhaust, a larger throttle body, and mild cams can be tuned in with the stock computer.
But once you get out of the mild performance arena and get into more serious mods such as big cams, super-chargers, or turbos, the stock computer simply can’t keep up. Even a bunch of smaller components that add up to bigger gains can over-whelm the stock computer and start to show its weaknesses. Ultimately, the computer can’t adjust the fuel maps and timing curves to compensate for the new air and fuel requirements on heavily modified engines.
For a simple aftermarket solution that does not require advanced tuning skills, the FAST EZ-EFI is a simple-to-use system that comes with all the wiring required to control the engine. This does not control the transmission; however, they are compatible with the TCI transmission controllers. (Photo Courtesy FAST)
If you need complete control over every aspect of your LS engine’s tune and have an electronically controlled transmission, the Dominator EFI ECM from Holley has everything in one box. (Photo Courtesy Holley Performance Products)
However, aftermarket engine management can, and they offer an array of tuning options.
Aftermarket controllers are an important consideration when using a crate engine. Chevrolet Performance crate engines do not come with a computer or wire harness, leaving it up to the buyer to get a harness and a computer. Chevrolet Performance does, however, offer a very good controller and harness for each of their crate engine offerings, including one for the carbureted LS364 and LS376 engines.
Chevrolet Performance Plug-and-Play Engine Controller
General Motors designed these controllers to help take the guess-work out of a Gen III/IV engine swap. Offered for the Gen IV–series engines, this controller works with the LS2 (PN 19166568), LS3 (PN 19201861), and LS7 (PN 19166567) crate engines. These controllers are complete standalone systems that allow the builder to simply plug the factory-style wire harness connections into the new controller and start the engine. No tuning, no removing codes or parameters—just fire it up. It’s a great option for builders who want a factory-based system and a specialized tune for a crate engine.
Carbureted LS engines are distributor-less, so you need an ignition controller such as this one from FAST. The XIM is also used with the XFI system on EFI engines. (Photo Courtesy FAST)
The Chevrolet Performance controller is based on the factory ECM, but features custom calibration of the electronic throttle control, EFI, and ignition systems. The Gen IV controller features an OEM-style fuse and relay center, with additional positions for other elective components, 12-wire bulkhead with outputs for the tachometer, VSS, oil pressure, malfunction indicator light (MIL), water temperature, and others. These signal outputs are compatible with aftermarket gauges only, and do not control factory electronic gauges.
The cooling fans and fuel pump can be controlled through the controller as well with the included out-puts. Each controller comes with a compatible drive-by-wire gas pedal, MAF sensor, and oxygen sensors. This controller regulates any LS-series engine that uses the Gen IV air/fuel components.
Using the Chevrolet Performance controller gives you the benefit of the vast testing labs available to General Motors, ensuring that this controller performs flawlessly with aftermarket components. It is also backed by the Chevrolet Performance warranty.
Chevrolet Performance LSX Ignition Controller
All OEM-installed engines are fuel injected but not all LS engines are fuel injected. Chevrolet Performance offers two carbureted LS engines for those who like the simplicity of a carburetor. The LS364/440 and LS376/515 engines are based on the LS2 and LS3, respectively, but are cammed up and topped off with Chevrolet Performance’s carburetor LS intake. The LS376/515 is the most powerful LS crate engine to date, pushing 515 hp at the flywheel.
Although these powerhouse engines run a classic carb on top, they use the LS distributorless ignition, which means that they need an ignition controller. The Chevrolet Performance LSX ignition controller module (PN 19171130) was developed for use with these carbureted engines, but works for any carbureted LS engine with a 58x reluctor wheel. The controller has several pre-programmed timing curves, along with software to create custom curves and adjust the rev limiters and step retard functions. The controller includes the MAP sensor and is compatible with all LS-series ignition coils.
Self-Learn Tuning
If you want to increase the tuning potential for your LS engine, there are quite a few options. The current entry-level controller for LS-series engines shares one key feature that greatly simplifies any LS swap: self-learning tuning. By eliminating the finer points of EFI engine tuning, the self-learn ECMs use data collected by the sensors to constantly tweak how the engine runs. This means automatic changes as the environment around the vehicle changes.
Let’s say you take a trip across the country. With a static tune, the engine runs differently at various elevations. With self-learning, the tune adapts to the environment much better than a static-tuned ECM. Once the engine is running, the ECM starts learning; within just a few miles, it has already begun to tune the engine automatically.
This means less time working on a laptop trying to get your engine running at its best and more time enjoying the drive. FAST’s EZ-EFI and Holley’s HP EFI systems both feature self-learn, and they are reliable controllers for the LS-series EFI systems.
If you want more control, you can have it. Even the basic self-learn systems have some user controls. The Holley HP EFI ECM can be manually tuned in addition to having the self-learn function. Where these entry and mid-level systems drop off is in the boost department. These controllers may not be compatible with superchargers or turbos; some are, while others are not. Just keep that in mind when making your decision.
Advanced Tuning
Although most aftermarket controllers are excellent in terms of engine management, most do not have transmission control for late-model electronic transmissions. A few, such as the Holley Dominator ECM, feature advanced tuning capability and include a built-in transmission controller. Others require a separate transmission controller.
This carbureted intake and controller from Edelbrock comes with a controller from MSD that mounts directly to the intake, eliminating mounting issues. (Photo Courtesy Edelbrock)
Several aftermarket transmission controllers, such as the TCI Transmission Control Unit (TCU) and Painless Performance’s Perfect Torc, offer greater tuning capability of GM electronic controlled transmissions than the factory controller. These units are compatible with most GM electronically controlled automatic transmissions. They provide load, gear, RPM, and speed-based programming with the click of a mouse.
The TCI unit is also fully compatible with CAN 2.0B engine management systems, such as the FAST XFI system, which makes it easy to integrate the TCU with the engine controller. Transmission controllers come with tuning software and wiring harnesses. The software allows you to change many parameters, even allowing paddle and pushbutton shifting configurations and manifold-pressure-based shift firmness, greatly adding to the ability to tune the transmission far beyond the capabilities of the stock TCM or ECM.
Feature Vehicle: 1967 Chevy Pickup
One of the most popular swap platforms is also one of the most popular classic trucks ever produced. With mil-lions made between 1967 and 1972, the classic C10 of this era is an extremely popular truck, and for good reason. They had excellent styling, great work, and haul potential, and are plentiful to say the least. Available in everything from a short wide-bed to Suburbans, there is a Classic C10 for everyone.
This 1967 C10 built by Red Dirt Rodz is a prime example of a restomod truck, using modern suspension updates, four-wheel disc brakes, and, of course, an LS-series engine. Here, a 2001 Chevy Vortec 5.3 and 4L60E automatic transmission were chosen. Not settling on just a stock swap, the 5.3 was treated to a host of aftermarket goodies from Holley, including a mid-rise modular intake, accessory drive, and Dominator EFI system.
This truck is different from many others because it does not have the typical short, wide body. It is a 1967 long step-side truck that had the perfect patina. Having spent most of its life as a farm truck in Montana, the truck was well used, but structurally intact. A four-wheel disc brake system was installed on the front drop spindles and factory 12-bolt rear end. Completing the suspension is a Ridetech air-ride system with tubular control arms and electronic controls.
When the 327 under the hood developed a knock, it was swapped rather than rebuilt. The 5.3 with 65,000 miles on the odometer was sourced from a salvage yard. With these engines commonly reaching into the mid-250,000 range without much issue, this is a fairly fresh engine.
The block was mounted to the stock frame rails using a set of Hooker LS motor mounts. Even though the stock Vortec components work quite well with this era of Chevy truck, most of them were swapped out for high-performance components. The accessory drive was changed to accommodate the modular Holley intake system that positioned the 90-mm LS3-type throttle body farther forward than the Vortec intake.
Written by Jefferson Bryant and Posted with Permission of CarTechBooks
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