This chapter discuss the connection and settings for the Optical CAS. For fault finding and testing see the Testing Magnetic Crank sensor chapter in this manual.

1. First ensure that the setup in Hyperspace is done according to the startup procedure. This means you will only have a P1 and P4 connector on the Mercury2. The other connectors must be open, except for the Comms cable. Open the software and connect to the ECU.
2. On the CAS there is a 360 slot output and a home or TDC slot output. The Spitronics ECU’s only use the Home slots. Connect it to the crank sensor input. These sensors the Crank is forced to rising edge and the Cam is disabled. In older software use the same settings. Gear Teeth is locked on 1 and Timing Sensor is usually between 60 and 65 degrees BTDC. Make sure the CAS is in its original mounting position where the bolt slides in the slotted groove. See the illustrations below:
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4. Ensure that the correct firmware is loaded into the ECU for the specific trigger pattern of your engine. You can click on information button to verify.
5. Make sure the Jumper settings are set for Hall sensors. On Mercury2 the crank sensor jumper must be closed. The cam sensor input is not used. Leave the jumper open. You may now crank the engine without the other connectors.
6. Ensure that battery volts on the Real-time Volt Bar does not fall too low. A healthy battery will crank at 11 volts and higher. Under 9 volts, the sensor signal becomes weak and falls below the voltage threshold of the specific ECU. Note: If it falls below 10 see chapter about ‘Power Connection’.
7. Look if any error codes are displayed at the bottom. If there are errors remedy the fault. See Error codes.
8. Look at the RPM signal in the Real-time Display while cranking. It should show 200 to 300 rpm consistently. If it shows erratic readings and runs wild do not proceed to start! It must be constant. It means the edge setting is wrong or incorrect firmware or there is interference on the trigger signal and the ECU sees them as trigger pulses.
9. If it shows no error and no RPM it means that the ECU does not pick up the signal from the crank sensor. Proceed to testing the crank sensor itself.

Testing the sensor.

1. The optic sensor requires power to operate. So it cannot be dry tested like a magnetic sensor.
2. First measure continuity from the ECU ground to the sensor ground. There should be 0 ohms as the earth comes from the thin black wire coming from the harness to the thick black earth of the ECU.
3. Measure continuity from the sensor power to the ECU ignition power that comes from the key. There should be 0 ohms.
4. Now measure continuity from the sensor signal to the ECU input for that sensor, see the drawing. You can disconnect P1 and measure on the pin.
5. The fastest way to test it is while it is powered in the circuit. While P1 is connected switch the ignition on.
6. Measure at the power at the sensor between negative and positive. You should measure around 12V DC.
7. Now unbolt the CAS from the engine. Make a proper mark so you can install it in the exact position. Measure DC volts between sensor negative and signal. It should be 12 volts and if you turn the shaft slowly it should go to 0 volt. If the voltage doesn’t go to less than 1 volt, then it means the ECU will not detect the change.
8. If you don’t measure the 12 volt on any condition on the sensor signal, it may be the pull-up jumper is not in closed position. If the jumpers are correct, then disconnect the sensor signal wire and measure at the ECU side for the 12 volt. If you measure 12 volts, it means the sensor output is damaged and short the signal wire to ground. If you don’t measure 12 volts then the ECU does not provide power through the pull-up resistor.
9. Now bolt the sensor in place and measure on the signal negative and positive with AC volts. Crank the engine and you should see 12 volts AC.

Errors and misfire during running or starting.

If the startup procedure tested correctly but you get errors during starting the engine, read through the following points.

1. The ignitions’ coils may generate interference spikes on the crank sensor wires. Ensure that the sensor wire is screened as close to the sensor as possible. If you connect to a distant connector there is usually a screen pin that has to be connected to the ECU harness screen.
2. The coils may spike the ECU and it may want to restart. This may be to incorrect supply currents or relay wiring. An indication of this error is that the software will lose connection momentarily to the ECU. A restart error will come up.
3. Errors that comes at higher RPM’s may be due to a weak pull-up signal. The sensor may require an extra pull-up resistor between the sensor signal and the sensor positive. Use a 1K resistor.
4. Ensure that the test signal next to the crank sensor is off.
5. Incorrect sparkplugs may generate feedback which leave spikes in the trigger signal. Normally resistor plugs are used for COP engines and non-resistor plugs for HT leads. Note: Ensure that you use carbon HT leads and not copper leads. Cracked leads also make interference. A trick is to look at them in the dark while it idles. It will show flashes in the dark.

Mercury2 pull-up

The Mercury2 use an isolated digital input to allow for magnetic sensor tap-in. For hall sensors an external jumper will connect a 1K pull-up resistor internally to the 12-volt power from the key. If this power is erratic due to other switching elements, then it may cause secondary triggering or interference of the input. To remedy this, you may add a 1K pull-down resistor to minimize the rippling effect on the power. If this does not help you may open the jumper and add a 1K pull-up resistor to 5-volt power from the ECU P1 pin 9. See the drawings below.