A MAP sensor is used to monitor your air intake system. MAP, which stands for manifold absolute pressure, and if its sensor fails, your car will stall or the idle will be very rough. In some instances your car may not even start. To get your car started again you will need to install a new one. Many people also choose to install an aftermarket MAP sensor because you can monitor greater pressure. A standard sensor will only have resolution of 22 inches hg, however, an aftermarket sensor can have a resolution of 30 inches hg.
Step 1: Mounting the New Sensor
You will need to mount your new sensor somewhere inside the engine bay area. If you are replacing an old sensor, you can remove it and put the new one in the same place. It can be easier to install the sensor if it is mounted on the passenger side of the engine bay.
Step 2: Vacuum Line and Wires
The sensor will need to have a vacuum source as the sensor measures vacuum. Many people choose to tie it into the same vacuum line that goes to the BOV. You want to connect the vacuum line that runs from the sensor to your chosen vacuum source. You will need to run all of the sensor wires through the firewall into the passenger side door. This is necessary as you need to wire the sensor into the power source of the old MAP sensor. When removing the old MAP sensor make sure you know which wire is the signal wire.
Step 3. Plugs
Depending on the type of sensor you have, connecting the wiring may be as easy as plugging the existing wire into the new sensor. Some MAP sensors will have several plugs and you will find the correct plugs in the ECU to use. This information should be readily available in your car manual. The ECU is normally found under the carpet on the passenger side.
Step 4: Bypassing the Old Sensor
If you are installing an aftermarket sensor, you will want to bypass the old stock sensor. You will need to splice the power wire from the new sensor into the power wire from the stock sensor. Do this also for the ground wire. You will need to have the signal wire bypass the UTEC harness. Cut this wire and tape off the end. Make sure you solder all wire splices for a sturdy connection. Once the old signal wire is bypassed you can attach the new sensor signal wire to the UTEC.
Step 5: Calibrating the Sensor
You will need to use the UTEC menu to calibrate the new sensor. These calibrations can be found under Edit Maps, Parameters, and Special Constraints. Here there are 2 MAP calibrations: one for the intercept and one from the gradient. Your aftermarket sensors will come with a minimum and maximum for the voltage and pressure and you can determine the intercept and gradient using these numbers. You can use a calculator or Excel to get the line equation.
Step 6: Make Sure it Works
Once your sensor is in and calibrated, drive it around to ensure that it is working properly. If you have any problems, it is most likely due to a loose wiring connection.