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Modern Diesel Power Engine Controls

Posted in How To: Engine on September 1, 2007
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For all of you who said technology was going to forever change the way we modify trucks, well, you were right. No longer will you have to bolt on dozens of add-ons in your search for seriously noticeable horsepower gains. With the advances in electronic vehicle controls, a chip no bigger than a half dollar can turn your mild work truck into a fire-breathing dragster in less time than it takes for you to read this article! These little plastic wonders range from small in-line boxes to full engine management systems that allow you to monitor and manipulate your engine's parameters from the comfort of your driver seat.

The technological evolution of these computer controls can be broken down into two main fields, OBD I and OBD II. What's OBD anyway? It's an acronym for On-Board Diagnostics that is designed to monitor your vehicle's emissions. The computer acts as a virtual nanny performing routine "check-ups" to make certain all systems are working correctly. When the vehicle reports back with unacceptable diagnostics, it creates that ever-annoying yellow glow on your dash that alerts you that something is amiss. The early version of this (OBD I) only monitored a limited section of your vehicle's emissions, and was deemed inefficient by government agencies that worked with the manufacturers to come up with the system that we currently use today (OBD II).

The plus side of the newer form of electronic control is that it gives you the ability to fine-tune your engine's parameters, allowing you to create more horsepower and torque by simply manipulating the factory settings. What all this means is that as technology grows, so should we. Whether you just want to scan a few codes or turn the inside of your cab into an F-16 control station, you need to know the basics. Just think of it as PlayStation for grownups.

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Performance-enhancing boxes can be one of the most effective means of pulling loads of potential power hidden within your truck. The box interprets outgoing signals from the engine and transmission that flow into the stock ECM. It then takes that information and manipulates it to make your vehicle believe that it's doing something it's not. The box's deception results in more fuel and modified transmission signals, which allow the vehicle to deal with the increase in horsepower and torque. Some boxes are set at a predetermined power level, while others can be controlled by the turn of a knob or flip of a switch, depending on the manufacturer's and customer's needs.

Designed primarily for early-model computers (OBD I), a replacement or plug-in chip replaces the OEM specifications with its own. From the factory your vehicle is designed for the average drive. This usually entails running low-grade gasoline, moderate driving conditions, and governed power to satisfy emissions regulations. Introducing a chip into the equation changes those factory parameters. This includes increasing your air-to-fuel ratio, advancing spark, and raising your rev limitations. When spark timing is advanced it begins the combustion event earlier. Engineers use this as a tool when designing a chip for your vehicle. The goal is to achieve more power and torque delivery at any give rpm.

These advances will free up a few ponies from your motor, but will require you to run a higher-grade fuel. One of the best aspects of a chip is that they are simple by nature. They don't require any special programming skills or technical degree to utilize them. They are pretuned devices that simply adapt to, or replace, your computer's existing system. As for emissions, most chipmakers have developed software to make them compliant with all 50 states, but ask about your specific application.

Working off the similar principles as the box, adjusting the power output from inside the cab allows you to choose from a broader range of settings. For example, if you need to haul a heavy load with your vehicle but your tuning parameters are set on the highest level, rather than risk damaging your motor or transmission you can simply lower the power from inside the cab to ease the stress on the vehicle.

When you activate different power levels the vehicle sends a signal to the box intercepting the ECM commands. In turn this only allows the vehicle to see a certain level of signals, thereby limiting the effect of the box's predetermined parameters. Another big advantage is the ability to monitor exhaust gas temperatures, fuel pressure, and the availability of built-in safety settings that will keep you from harming the engine and provide you with warning tones when zones are bordering their limits. Most will allow you to fine-tune performance numbers such as 0-60 and quarter-mile times, and work as a scan tool to retrieve engine codes.

One of the most user-friendly and helpful devices is a plug-in programmer. It works by simply plugging into the existing OBD II port and downloading the factory information into the tuner and then offering you a list of preset upgraded tuning levels that you can upload. These controllers allow you to check and scan engine codes, adjust shift points, raise top speed, adjust rev limit, and provide you with the option of simply returning the truck back to stock if you ever feel the need. The programmers have been known to provide huge horsepower and torque numbers and, when stacked with a box, can be even more potent. Look for upcoming articles where we show you just what stacking boxes can do.

Some of the downsides to a plug-and-play such as this would be the inability to quickly change programming settings. This means if you have your program set on extreme and you want to go down to a lower mode such as tow, you will have to plug the controller back into the port and go through the programming cycle. This does not take long (on average under five minutes) but if you so happen to not have the programmer in the truck, you are stuck with whatever setting you have it tuned to.

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