OMEM200 Installation Manual 2v10 Introducing Omex Engine Management Thank you for choosing Omex Engine Management. This manual is written to help the user through the specifics of installing the OMEM200 ECU. It is essential that the user reads the whole of the manual before attempting to install the system.
Omex can supply general purpose trigger wheels in diameters of 100mm and 140mm.
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OMEM200 Installation Manual 2v10 If machining a trigger pattern into the front pulley then it is usually easiest to machine all of the teeth in, mount the front pulley, and then remove the tooth pointing at the sensor at 90 BTDC.
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OMEM200 Installation Manual 2v10 Sensor Type Jumper Position jumper Hall Effect...
When the throttle position is moved from closed to open, the resistance does not change between 1 and 3. Therefore, 2 must be the signal (Omex orange). 3 has the lower resistance to the signal with the throttle open and so must be the 5V (Omex pink), leaving 1 to be the sensor 0V (Omex grey).
If fitting a sensor to an engine that does not have one as standard, the sensor must be fitted to the engine side of the thermostat so that it sees the engine’s coolant temperature even when the thermostat to closed. Omex can supply suitable sensors.
OMEM200 Installation Manual 2v10 2.4 Air Temperature Sensor (ATS) The air temperature sensor is used to give the ECU information on the temperature of the inlet air. This allows corrections to the ignition timing to suit varying conditions. This sensor is optional as this control is only required on engines that see large temperature changes, typically only forced induction engines.
OMEM200 Installation Manual 2v10 2.5 Manifold Absolute Pressure (MAP) Forced induction engines need a MAP sensor to give the ECU a reading of manifold pressure (boost pressure). In some cases a MAP sensor is used to measure engine load on NA engines but this is rare. MAP sensor ratings are absolute rather than boost pressure so 1bar is for normally aspirated (NA) non-boosted engines, 2bar for up to 1bar boost, 2.5bar for up to 1.5bar boost, and 3bar for up to 2bar boost.
OMEM200 Installation Manual 2v10 2.6 Ignition Coil(s) The ECU is fitted with two amplified ignition outputs. This allows the following types of ignition; Single Coil and Distributor yellow 12V from power relay violet Both ignition outputs from the ECU go onto the coil negative terminal. The distributor can be left as standard but all that is now used are the rotor arm and cap;...
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Between the 12V terminal and one of the signal terminals (also known as coil negative) a non-amplified coil will measure approximately 1Ω. An amplified coil pack will measure several kΩ. Amplified coil packs can be used if necessary, but are not ideal and the ECU hardware must be modified by Omex to allow this. Known wiring...
12V specific LED or must have an inline resistor fitted. An LED will glow slightly all of the time then turn on bright at the shift point. Omex can supply shift light LEDs that are fully off normally. If a filament bulb is used it will be fully off then fully on at the shift point.
‘tacho driver’ available from Omex to give a voltage spike to trigger the tacho. Some very old tachos were ‘current’ driven and triggered from coil positive. Omex can supply a convertor box to allow...
OMEM200 Installation Manual 2v10 2.9 Fuel Pump Although it is normal for the fuel pump to be physically ignition switched, for extra safety it can be ECU controlled. When power is first given to the ECU it will turn on the fuel pump output for 2 seconds to prime the fuel system.
OMEM200 Installation Manual 2v10 2.10 Radiator Fan The ECU has two software outputs switchable on coolant temperature values. These would normally be used for radiator cooling fans. The two outputs may be set to two different temperatures to control two fans or a single twin speed fan. The radiator fans are not driven directly by the ECU, they must be controlled through a relay.
Infinitely variable VTEC (such as Honda i-VTEC, Rover VVC etc) cannot be controlled by this function and require the Omex 710 ECU. Single Wire Solenoid 12V from...
Pin 10A (white / yellow) must be switched to earth to trigger the full throttle gearshift. Clutch switches are available from Omex. ECU FTG input White / yellow Earth 2.13 Alt Mode...
OMEM200 Installation Manual 2v10 Wiring 3.1 Semi Assembled Loom Construction The engine bay is a harsh environment for wiring harnesses with oil, water, solvents, high temperatures, high vibration, and high electrical noise. The semi-assembled wiring harness is made from automotive grade cable and the shielded cables are already made-up at the ECU connector to prevent electrical noise problems.
OMEM200 Installation Manual 2v10 4.3 ECU Connector It is occasionally neccessary whilst fault finding to trace through your wiring harness to check continuity. The following are the pin-outs for the ECU plug as found on the end of the wiring harness. Where there are two colours on a cable, the main colour and the tracer colour can be either way round.
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OMEM200 Installation Manual 2v10 number colour code function Violet Ignition 1 Battery power Black Chassis earth 1 Grey Sensor ground Black screened red Crank sensor Blue cables from the inside of Timing ground the screened cables White / violet Coolant temperature sensor White / yellow FTG input Yellow...
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