Mazda EC2-A 13B Engine Controller PDF Installation And Programming Guide

Thanks for purchasing the Real World Solutions EC2 engine controller for the 13B Mazda rotary. We have endeavored to make it the most versatile and reliable controller on the market today. Needless to say, the quality of installation is just as important as the quality of the hardware itself. It is not practical to include a course on proper electrical wiring practices in these installation instructions, but it is imperative that proper wiring techniques be employed during the installation of the EC2. Good connections and proper strain relief are crucial to system reliability. If you are not comfortable with reading a wiring schematic or wiring of electrical equipment, find someone to assist you. If you are in doubt about any of the instructions that follow, please contact me before operating the controller. I want your project to succeed and your life to be a long and happy one.

MATERIALS & TOOLS REQUIRED
1. Small Soldering iron
2. 63 – 37 or 60 – 40 rosin core electrical solder
3. 16,20 & 22 gauge stranded wire (See “Fuel Injector Wiring” for details.)
4. 1/16” ID heat shrink tubing for insulating connector solder connections DigiKey PN VFP116-X-ND ( X= how many feet you want)
5. 5/32” vacuum line to connect EC2 MAP sensors to manifold vacuum ports (Available at Auto Parts stores) ) Do NOT use hard nylon or plastic line as this could damage the sensors due to the difficulty of removing them.
6. 2 DPDT switches rated at 10 or more amps (Switches are optional. See “Injector Failure Backup Mode” for details.)

INSTALLATION CAUTION: Make sure the positive terminal of the battery is disconnected during installation of the EC2 or any other electrical equipment. Damage caused by failure to heed this warning or due to incorrect wiring of the EC2 will not be covered under the warranty. Any other failure resulting from normal operation of the controller will be repaired at no cost except for shipping charges. CONTROLLER Begin by selecting the mounting location for the EC2 controller. This location should be as close to the engine as practical but not on the engine side of the firewall. It must be on the cockpit side in order to avoid exposure to engine heat and vibration. Remove the EC2 cover, on which the circuit board and connector are mounted, by removing the 4 countersunk Phillips head screws at the four corners of the case. Set the controller aside in a safe place while mounting the case. Mount the controller case by drilling mounting holes in the back or sides. If at all possible, mount the case directly to a grounded part of the airframe. The controller may be mounted vertically or horizontally. It is critical to isolate the unit from engine heat and excessive vibration. Choose a location with enough clearance for the wiring harness and connector; four inches or better is recommended. Be sure to remove all metal chips and dust from the case before reinstalling the controller and cover. You may paint the case if you wish, but do not paint the mating surface between the cover and case.

It is important there be electrical contact between the cover and the grounded case. I would also suggest that the EC2 be installed in an easily accessible location where you can visually verify that the connections to the EC2 are properly made. In one case, we spent several weeks troubleshooting (via long distance phone and shipping the unit back several times) only to find out that the builder was installing the controller backwards so that the manifold pressure sensors were not behind the slots in the case. The vacuum lines were being pushed into the slots by feel alone since the controller was buried far underneath the instrument panel. He thought the lines were plugged onto the sensors but they were not. All external connections to the EC2 are protected from static damage, but do not touch the components or circuit board when they are exposed to avoid any possibility of static damage. If at all possible, the controller case should be mounted to an electrically conductive part of the aircraft structure that is connected to the negative terminal of the battery. If this is not possible, the EC2 case must be grounded to a conductive part of the airframe (engine mount, instrument panel, etc.) with as short a wire as possible. There is a ground stud on the top of the EC2 case for this purpose. Connect a ground wire from this stud to the airframe, even if the case is mounted to the airframe (this should be at least a 16 gauge stranded wire). PROGRAMMING & CONTROL MODULE (PCM) Next choose a location for the Programming & Control Module (PCM) where it can be easily accessed in flight. The control module comes mounted on a labeled plate to be mounted on the instrument panel in an easy to reach location. Because the placement and configuration of the controller will vary greatly depending on the aircraft being built, it is not possible to furnish a pre-made wiring harness. Connectors for building the wiring harness are included with the controller. All wiring should be done with 22 and 20 gauge wire as indicated on the “Terminal Assignments and Destinations” sheet at the end of this document. Use wire that meets specification MIL-W-22759/16 or similar high quality wire.

This is available from Aircraft Spruce & Specialties and other aircraft suppliers. Remember that the reliability of any electronic device is no better than the wiring and connections used to install it. TEMPERATURE SENSOR MOUNTING The temperature sensor should be mounted in such a way that it is exposed to the incoming air to the throttle body. Use any suitable means of securing the sensor, such as a non-metallic cable clamp. I would suggest gluing the sensor into a threaded fitting such as an AN816-4 if you want to use it in a location where threading it into an intake manifold bulkhead or plenum would be advantageous. J-B Weld epoxy or a non-corrosive RTV rubber adhesive may be used for this purpose, but make sure that the sensing end of the device remains exposed to the incoming air stream. Do not cover it with adhesive. Note that only controller A has a temperature sensor. The backup controller (B) has no temperature sensor in order to eliminate this as a possible failure mode. The two wires on the temperature sensor are interchangeable. Note that one of the connections for the temp sensor has been changed from earlier versions. It is now connected to pin 1 (ground) instead of pin 11 (+5) in order to eliminate a failure mode in the event that the wire shorts to ground causing the controller to stop.

WIRING HARNESS I suggest doing all wiring and soldering of the EC2 harness connectors at a comfortable workstation with good lighting. The close spacing and small size of the connector terminals require very careful work. Trying to do this while bending over the control panel in the airplane will almost certainly result in unsatisfactory results. When wiring the connector, use 1/16” I.D. heat shrink tubing to insulate each of the soldered terminals. For a source of pre-wired harnesses, see our Website for contact information on Bob White who does top notch electrical work and builds pre-wired harnesses for the EC2 at a very reasonable price. You should begin wiring the system together only after the fuel injectors, coil assemblies, air temperature sensor, EC2 controller, and the Programming & Control Module are installed. After all components of the system are in place, use the “Terminal Assignments and Destinations” sheet (at the end of this document) to determine the length and gauge of each wire to be soldered to the connectors. Pre-cut all wires and label them about 5 inches from each end with a piece of tape or by other suitable means. Take the two connectors (for the EC2 and PCM) and the precut wires to your workstation and solder all connections to the connectors. If the physical layout of your electrical wiring will allow you to mount the Coil Test switch in its final location later, you may also solder the connections to the Coil Test switch (furnished with the controller) at this time. When wiring the EC2 and PCM connectors, refer to the drawings included on the last page of this manual to determine the pin numbers. The drawings show the back of each connector. This is the side to which you will be making the soldered connections. If you look carefully, you can see that the pin numbers are molded into the back of the connectors. CAUTION: The order of the pin numbers on the EC2 connector is different from the order of the pin numbers on the PCM connector.

FUEL INJECTORS TYPES OF FUEL INJECTORS There are two basic types of fuel injectors available. Mazda used both types, so you must determine which type you have in order to wire them to the controller properly. The two types are “Peak & Hold” and “Saturated”. To determine which type you have, measure the electrical resistance between the two terminals on the injector. The Peak & Hold type will measure between 2 and 3 ohms. The Saturated type will measure between 11 and 16 ohms. The Peak & Hold type requires an external resistor in series with each injector to limit the current flow. You can use a resistor pack from an RX7 car, but I would recommend using Mil Spec resistors. We can supply the recommended resistors ($25 for a set of 4), or you can purchase them from an electronics supply house. You will need 4 resistors rated at 5 ohms and 25 Watts. You can use virtually any fuel injector that has a sufficient fuel flow rating. I chose to use the stock Mazda injectors that came on the engine. The EC2 is set up to use 4 injectors (two per rotor) with staged injection. “Staged injection” means that only two of the injectors are active at low throttle settings. At higher power settings (above 15” Hg manifold pressure) all four injectors are active. I recommend that you obtain new fuel injector connectors rather than using the old ones from the car wiring harness. I purchased mine at a Nissan dealer. The Mazda injectors use the same connectors found on a Nissan 300ZX car. Be sure to take an old connector with you (or better yet, an injector) to be sure that the ones you get are the same type and are keyed the same way. Splice the wires from the EC2 connector to the injector leads and insulate the connections with heat shrink tubing. FUEL INJECTOR WIRING When wiring the injectors, note that the two wires from the injectors are interchangeable. Also note that rotor 1 refers to the front rotor as it is positioned in the car (this is the rotor closest to the crank angle sensor). Rotor 2 is the one closest to the flywheel end. “Primary injectors” refers to those mounted directly on the engine block, which feed the inside ports. The secondary injectors are mounted on the intake manifold and feed the outside ports. Note that the injector return lines from the EC2 connector (pins 19 & 37) and the injector control lines (17, 18, 35, and 36) should not be bundled with the other wires in the harness. These lines carry relatively high current that is switching on and off. This can induce noise into the other lines if they are bundled together. Bundle these 6 wires separately from the others. The injector current return pins (19 & 37) should be connected to ground on a conductive part of the airframe near the EC2. These two wires from the EC2 should be as short as possible. Figure 1 shows the recommended injector wiring. Installation of the two DPDT switches shown is optional (they are not included with the EC2).

They should be rated at 10 amps or more. Wire the power connections on the injectors directly to a +12 V (battery) power bus if the switches are not used. Do not wire the injector power leads directly to the battery without a switch. The EC2 will power itself through the injectors and drain the battery. In other words, power to the injectors should be switched off when the engine is shut down. On the subject of aircraft electrical systems, I use two separate power busses in my airplane. The main bus I call the “Flight Critical” bus because only the things necessary to make the engine run are hooked to it. This bus is connected to the battery through a combination switch/circuit breaker rated at 50 amps. This is the bus you should use to power fuel pumps, ignition modules, fuel injectors, and the EC2. A 40-amp switch/breaker powers the other bus, which supplies all the non-essential stuff (radios, instruments, lights, MP3 player, and other accessories). If you elect to install the switches, wire them as shown in Figure 1 below. This allows power to be removed independently from the primary or secondary injectors. If, for instance, a primary injector were to fail, the primary injectors could be switched off. This would, of course, reduce the fuel delivered to the engine by half. To compensate for this, the Cold Start input to the EC2 is activated, which doubles the fuel delivered by the remaining two injectors. In this configuration, the engine will continue to run on the secondary injectors alone. This emergency procedure would work equally well if the secondary injectors were to fail. Disabling the secondary injectors would allow the engine to continue running on just the primaries. Engine power in this emergency mode would be limited to about 80%.

Download Mazda EC2-A 13B Engine Controller PDF Installation And Programming Guide