Megasquirt PNP PSA 16V Installation

Megasquirt Plug and Play for Citroen Saxo 1600 16V and Peugeot 106 GTI 1600 16V with original Magneti Marelli 55-pin ECU. This 100% programmable ECU is installed in the vehicle as if it were an original unit, it only needs a cable to be connected from the additional connector at the rear to ground, and after performing the checks recommended in this manual, you can start tuning the engine without any limitations.

The unit has a 14-pin sealed connector at the back for PC communication and CAN BUS. You will also find outputs that allow you to control solenoids, warning lights, or relays, inputs that enable Launch control, Cut-Off, dual fuel and ignition maps, Cut-Sifth for sequential gearboxes, and other functions. The connector has numbered pins, for clarification, the following image shows how they are distributed, both on the ECU connector viewed from the front and on the wiring connector viewed from the side where the wires are inserted.

Each pin on the connector is an input, output, or used for CAN BUS or RS232 communication. The following list shows the names of each output or input, which are the same ones you will find in the Tuner Studio program for configuration:

• Pin 1 - PE1. Ground switching input for Launch control, Cut-Off, Dual fuel and ignition maps, Cut-Sifth on sequential gearboxes, and other functions.
• Pin 2 - PA0. Ground switching input for Launch control, Cut-Off, Dual fuel and ignition maps, Cut-Sifth on sequential gearboxes, and other functions.
• Pin 3 - FIDLE. Ground switching output for solenoids, warning lights, relays, etc...
• Pin 4 - SPARE ADC. ADC input (analog to digital conversion) for pressure, temperature sensors, etc... It can also be used as a ground switching input for Launch control, Cut-Off, Dual fuel and ignition maps, Cut-Sifth on sequential gearboxes, and other functions.
• Pin 5 - SPARE ADC 2. ADC input (analog to digital conversion) for pressure, temperature sensors, etc... It can also be used as a ground switching input for Launch control, Cut-Off, Dual fuel and ignition maps, Cut-Sifth on sequential gearboxes, and other functions.
• Pin 6 - Ground to engine block. It is necessary to connect this cable to ground, otherwise the unit will not function.
• Pin 7 - FLEX. Input for Flex Fuel sensor. It can also be used as a ground switching input for Launch control, Cut-Off, Dual fuel and ignition maps, Cut-Sifth on sequential gearboxes, and other functions.
• Pin 8 - CAN L. CAN BUS communication with external modules or display.
• Pin 9 - CAN H. CAN BUS communication with external modules or display.
• Pin 10 - WLED. Ground switching output for solenoids, warning lights, relays, etc...
• Pin 11 - ALED. Ground switching output for solenoids, warning lights, relays, etc...
• Pin 12 - Communication ground, pin 5 DB9. Communication with PC.
• Pin 13 - TX pin 2 DB9. Communication with PC.
• Pin 14 - RX pin 3 DB9. Communication with PC.

Communication, input, and output connections are explained below:

Ground switching inputs:

These inputs are PE1 and PA0, supporting 5V and 12V. Remember that if you need more inputs of this type, you can use SPARE ADC, SPARE ADC 2, and FLEX, which only accept 5V. They are used with a switch, button, or a similar mechanism to enable the ECU to perform a specific function like Launch control, Cut-Off, switching fuel and ignition maps, or Cut Sifth (with programmed cut times) for sequential gearboxes. While the input is grounded, the ECU will perform the programmed function; when not grounded, it will work normally. The way to make the connections is as shown in the following image:

ADC Inputs:

These inputs allow converting a sensor’s voltage into a measure, such as pressure, temperature, etc... They can also be used as ground switching inputs if necessary. They only accept 5V.

Temperature sensors need to install a 2.49K resistor, as shown in the following image:

FLEX:

This sensor detects the amount of alcohol or ethanol mixed with gasoline and adjusts the fuel and ignition based on its reading for precise and reliable tuning. It can also be used as a ground switching input, only accepting 5V. The FLEX sensor connection depends on the model used, usually a single signal cable is connected to the unit.

Ground switching outputs:

These outputs allow controlling solenoids (e.g., turbo pressure control), warning lights (e.g., gear shift indicator), or relays (e.g., controlling the radiator fan startup). The maximum current these outputs accept is 3A. Some example connections are shown below:

CAN BUS:

Connection via CAN BUS with external modules or displays. The connection is as shown below:

PC Communication RS232:

Communication with the PC is done via RS232 with a DB9 connector. Nowadays, it is rare for laptops to have this port, so you will need an RS232 to USB adapter, which you can find in engine management / wiring and communication.

The ECU connection to the DB9 is as shown below:

Checks to be performed during installation:

Remember that you can request start-up assistance when purchasing the unit, and through remote connection to your PC, we will help you perform the checks. The checks to be performed are:

• Check the functioning of the injectors and their injection order.
• Check the functioning of the coils and their ignition order.
• Check sensor calibration and recalibrate if necessary.
• Ignition timing with strobe light.

You may think everything is correct in your installation, and it probably is, but we have often found surprises and recommend everyone perform these checks before starting the engine. You can use the unit's test modes for this. If you hire start-up assistance, we will help you with these tests.