Elementary EFI: Electronic Fuel Injection Doesn’t Have To Be Voodoo
Wayne Scraba
Click Here to Begin Slideshow
EFI has been around for decades in production line cars and it’s been available over the counter as a retro fit for considerable time, but there are still plenty of us out there who are spooked by the systems and we tend to stick to carbs. Most figure there’s a considerable amount of Voodoo involved and it’s all really too complex. That was then. The reality is, EFI isn’t that difficult and with the entry-level EFI setups out there, installation, setup, operation and reasonable cost might be a whole bunch easier than once imagined.
One of the easiest setups to deal with is MSD’s Atomic EFI. With MSD’s Atomic EFI Master Kit (Part Number 2900), you get pretty much everything needed to convert your car or light truck from a carburetor to fuel injection. MSD includes the throttle body, a power module (complete with a wide band oxygen sensor), fuel pump, filter, a handheld controller and all of the necessary small parts.
According to MSD, “the Atomic Throttle Body Injection system is the easiest way to convert your classic car to EFI. As far as performance, the advanced self-learning technology of the Atomic is constantly monitoring and analyzing the engine’s operating conditions ensuring that you receive the best possible driveability. With the ECU and built-in sensors integrated into the throttle body, the Atomic has fewer wiring connections than any other system, plus there is no bulky ECU to mount. This design makes the conversion to EFI much easier to install and program while keeping things clean under the hood.”
What you get with the Atomic EFI is great performance and superior drivability. Your car will start quicker, have a smoother idle and it will have great throttle response. In addition, the MSD system is designed so that it is easily integrated with a conventional MSD ignition box. It allows you to control initial timing by way of a small handheld monitor (this can be removed once the car is running or you can leave it in place allowing you to monitor engine parameters in real time). For integrated timing using an MSD ignition system an adjustable rotor is needed to correct rotor phasing (MSD part number 84211 for most MSD Distributor applications). And believe it or not, the system can actually operate with an old-fashioned point trigger ignition!
That answers the benefits part of the equation, but how many pieces are there and are they difficult to hook up? Let’s start at the top:
There are three main components of the Atomic TBI; the Throttle Body, the Power Module and the Handheld Monitor. The brains of the system or the ECU is built right into the passenger side of the throttle body and there are also several sensors built right into the unit including the Throttle Position Sensor (TPS), Manifold Absolute Pressure (MAP), Intake Air Temperature (IAT) and the Fuel Pressure Sensor. What this means is you don’t have to mount those sensors or hook them up.
The throttle body is designed so that it bolts right up to a common square bore (Holley 4150 style) intake manifold pattern. It’s also shaped so that an equally common dropped base carburetor air cleaner fits right over the top. On the driver’s side, the throttle bracket will accept all normal cables; return springs and transmission control cables. You just have to remove the various bits from your carburetor and transfer them over. There are no external fuel rails. MSD incorporates internal passages within the throttle body to supply fuel to the four integral injectors. Externally, you simply have to hook up the supply line (from the fuel pump). MSD provides you with a choice of a -6 AN hookup or a barb fitting hookup for the fuel line on the throttle body.
The Power Module of the Atomic EFI is simply the communication hub of the system. What it does is to provide the high current fuel pump circuit and other input/outputs for optional features. It is equipped with two ports for the MSD “CAN System” as well as a wiring harness. There are connections for the wide band oxygen sensor, the special handheld control module as well as power and communication to the throttle body.
The Handheld Control Module (which simply plugs into the Control Module) is what you use to set up the EFI system for your car. You use a basic joystick device for initial (and later advanced) setup. For initial setup, you enter your engine displacement, number of cylinders, camshaft specs (based upon duration at 0.050-inch tappet lift), fuel pump type, target idle RPM and finally, you must select if you want the ECU to control the ignition timing or if you want it to function with a standard “you set it” ignition timing arrangement. After the initial setup selections are answered and the engine is running the hand held control can be removed or left connected. When it is connected, there is a “Dash and Gauges” screen that shows engine parameters in real time. Cool.
After the basic setup is established, the Atomic EFI system will do everything else for you. MSD explains: “It is a self-tuning EFI system that continuously adjusts after the basic configuration is complete. There is no laptop programming. Based upon the engine descriptors that you input during the initial setup, the Atomic will automatically create a base fuel map to get the engine running. Once the system is started the self-learning technology will optimize those maps resulting in the best performance possible. If you drive through altitude changes, temperature swings or other factors the Atomic will adjust accordingly, on the fly. This ensures that your engine will produce excellent drivability at all times, even from the sunny coast to the cool mountains.”
At this point, we’ll wrap up this segment. In a few weeks, we’ll complete the overview. In the meantime, check out the accompanying slide show:
Click Here to Begin Slideshow
These are the basic components found in Atomic EFI master kit from MSD. Most of the electronics and hardware is built right into the throttle body. The balance is an easy bolt in with minimal wiring (and most of that is plug and play).
With the Master Kit, MSD includes a Pulse Width Modulation fuel pump (more info in the text) capable of supporting 500 HP. An optional fuel pump kit (MSD Part Number 2921) can support 620 HP. Two filters are included in the Master Kit – a pre filter and a post filter along with 15 feet of high-pressure hose, mounting brackets and high-pressure hose clamps.
A special (extremely sanitary) throttle body that includes an integral ECU is the key to the system. It fits on any 4150 square bore intake manifold. More in the next photos.
The throttle linkage arm is designed so that it will fit a wide range of applications. That means you can (for example) work with an existing automatic transmission kick down, cruise control linkage, throttle return springs and so on.
That very nice finned cover is actually the ECU. You don’t have to touch it.
