370z Input / Output Hijack
Hijacked Inputs
There are 2 ways to get external signals into the factory ECU to enable display and additional ECU functions using custom maps. These inputs need to be 0-5V analogue signals so any attached sensors will need to be setup to output within this voltage range. The current list of inputs are
- CPC Pressure Sensor
- MAF Sensor Voltage B1 & B2 (requires full time Speed Density)
The strength of the hijacked inputs comes from their uses as an axis or activation threshold in custom maps. To use a hijacked input in custom maps you need to select the desired input as the definition for the axis or activation parameter.
To re-purpose an input simply select it as an axis definition, keep in mind that custom inputs from ECU connect are also available and may prove more simple for switches etc. Each of the 2 inputs has a specific pin at the ECU, you can cut and splice into the original wiring at the ECU multi-plug or possibly locate an OEM style plug the same as the sensor it once connected to for a neat installation.
CPC Pressure Sensor
The ECU measures the carbon purge canister pressure at the fuel tank, however this input is easily hijacked. We would recommend using the latest RaceROM feature file and using the CPC pressure sensor voltage as an input for flex fuel sensors or multi-position potentiometers. The pressure sensor is located at the rear of the car and routing wiring would be difficult, therefore it would be easier to connect any external device wiring directly to the wiring loom at the ECU Multi-plug.
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Some region vehicles do not come equipped with CPC pressure sensors. In those instances you'll need to add a pin to the ECU directly for it to work properly. |
MAF Sensors
When running full time speed density the MAF sensor signals are no longer required by the ECU and can be re-purposed to receive any 0-5V analogue signal like that from fuel pressure transducer, fuel temperature sensor, pre throttle boost pressure sensor, Nitrous Oxide activation signal or even on/off switches.
You can import external sensor signals at the under bonnet wiring loom sensor connector or at the ECU depending on your preference.
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If you fully remove the MAF sensors you will need to fit "stand alone" Intake Air/Charge Air Temperature sensors |
Using the Inputs
Any 0-5V input that is imported through a Hijacked sensor must be interpreted by the ECU in some way, which means it must be scaled. If you are using the input as an axis value you may want to use a direct 0-5V scale.
If you are importing an ethanol sensor or a fuel pressure sensor it should be converted from 0-5V into the value that you are using, this means that you can log the parameter value by logging the custom map input. Something similar to below, where the axis is 0-5V and the map output being the same scaling as the sensor 0% ethanol at 0V and 100% ethanol at 5V.
Hijacked Outputs
There are several outputs that can be hijacked in the 370Z, similar to inputs they are restricted by the ECU hardware as to what the can do. Once again custom maps is the key to driving these outputs and need to be set up accordingly. The current list of physical outputs that can be hijacked are
- CPC solenoid valve
- CPC vent control valve
Canister Purge Solenoid Duty %
The canister purge solenoid output utilises the factory hardware to drive a solenoid valve at 11hz. At this time the frequency is fixed and cannot be adjusted to suit other valves but 11hz gives reasonable results.
As we are hijacking the OEM functionality the DTC’s for this system will need to be disabled to prevent the car from going onto a limp mode.
The wiring options are as follows
CPC Vent Control Valve
The Vent Control Valve is a simple on off valve that can be hijacked as required. This can be useful to switch controllers for nitrous, intercooler pumps or water injection on and off as per your requirements. The Vent control valve is not suitable for duty cycle application and should not be used for a PWM boost control solenoid.
Specific DTCs for the Vent control valve will also need to be switched off
Driving the Outputs Using Custom Maps
To drive the outputs you will need set up the output of the custom map to the correct channel and populate the maps as you desire for more information on how a boost or duty output can be set up consult the custom maps manual. They normally look something like this.
