370z Sensor Input / Output Hijack
- Brandyn Mowat
370z Input / Output Hijack
Hijacked Inputs Using RaceROM Custom Sensor Input/Outputs
WIth the custom sensor inputs code from EcuTek, you're able to run a variety of other sensors on your vehicle without any expensive external boxes. The types of sensors you can currently add are essentially infinite, but we've gone ahead and hard-coded tables for a few of the most common ones to make things easier.
The sensors we offer hardcoded tables for are.
- Coolant Pressure
- Ethanol Content / Flex Fuel Sensor
- Fuel Pressure
- Manifold Absolute Pressure
- Mass Air Flow
- Oil Pressure
While these sensors are already set up in the RaceROM files you can add any sensor you want using custom maps. Check out the section below Hijacked Inputs Via Custom Maps (Old Method) for a better idea of how to do so.
Each of these sensors gets the same setup tables so you can have a consistent workflow no matter which one your'e doing.
- Sensor Default
- Sensor Max
- Sensor Min
- Sensor Scaling
- Sensor Smoothing
- Sensor Source
Sensor Default
In the event of a failure of some kind in the circuit (wiring, fuses etc.) the value will default to whatever is in this table. In the case of some things like ethanol content it typically works best to set this closest to what the user will have in the car the majority of the time. It's also possible to use this value in conjunction with the new failsafe tables to throw the car into limp mode should your sensor or wiring fail.
Sensor Max
The maximum voltage output considered to be normal for the sensor. Set this to the value specified by sensor kit's manufacturer. In some cases if the sensor could feasibly hit that value during normal operation you may want to add a small amount of room between the sensors limit and the max voltage to avoid getting unnecessary DTC's. (i.e. if the sensors min voltage is 4.5v, set it to 4.6)
The ecu itself has a default voltage biasing of 4.75v on the spare ECU input pin (Pin 60). As such using that specific voltage can cause erratic behaviour. It's recommended to go either above or below that value to ensure proper operation.
Sensor Min
The minimum voltage output considered to be normal for the sensor. Set this to the value specified by sensor kit's manufacturer. In some cases if the sensor could feasibly hit that value during normal operation you may want to add a small amount of room between the sensors limit and the value in this table to avoid getting unnecessary DTC's. (i.e. if the sensors min voltage is .5v, set it to .45 or .4)
Sensor Scaling
Sets the relationship scale for voltage against the sensor's output value. (Pressure, ethanol content etc.)
Sensor Smoothing
A smoothing value to be applied to the output of the LPFP sensor to reduce the impact of the minor fluctuation in content seen by most pressure sensors. 0 is full smoothing 1 is no smoothing. Comes in handy if the sensor is sensitive which can cause undesirable spikes in values.
Sensor Source
Establishes the ECU input referenced for your sensor. Choose whichever sensor you have plugged the sensor in through.
Hijacked Inputs Via Custom Maps (Old Method)
This method will be used if you're wanting to set up a sensor input/output other than those hardcoded into the RaceROM Custom Sensors.
There are 4 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 possible inputs you can use would be
- CPC Pressure Sensor
- MAF Sensor Voltage B1 & B2 (Require tuning the vehicle for full-time speed density
- Heated O2 Sensor2 B1 &B2
- Aircon Pressure Sensor
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.
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.
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.
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.
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.
If you fully remove the MAF sensors you will need to fit "stand alone" Intake Air/Charge Air Temperature sensors
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
Input Options and Setup
Air Conditioning Pressure Sensor Setup and Use (Input)
Using the Aircon Pressure sensor will require wiring to the sensor harness in the engine bay or at the ECU. You'll want to disable DTC’s in the AC module and ECU.
Rear O2 Sensor Setup and Use (Input)
Using the rear O2 sensors should be done for off road use only. See the diagrams below for pinout specifics.
Canister Purge (CPC) Pressure Sensor Setup and Use (Input)
The ECU measures the carbon purge canister pressure at the fuel tank, however this input is easily hijacked. We would recommend using the latest patch and using the CPC pressure sensor voltage as an input for flex fuel sensors or multi-position potentiometers. The pressure sensor is at the back of the car but you could wire directly to the ECU if you wish.
MAF Sensor Setup and Use (Input)
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.
If you fully remove the MAF sensors you will need to fit "stand alone" Intake Air/Charge Air Temperature sensors.
Output Options and Setup
Canister Purge Solenoid Duty % Setup and Use (Output)
Used as a duty cycle output from ECU
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 Setup and Use (Output)
Used as On/Off Output from ECU
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
