How To Install a 3 BAR MAP Sensor

How To Install a 3 BAR MAP Sensor


If you are planning to turbo your Honda or Acura by installing a turbo kit, knowing how to install a 3 bar MAP sensor is vital. Even if you don’t plan on exceeding the stock Honda MAP sensor’s limit of 11 psi, it’s a good idea to know what the 3 bar MAP sensor does that your stock unit can’t.

Many customers get confused when it comes to the term BAR or what that unit of measurement means when coming to pressure. Not to be confused with California’s complex means of legalizing your engine swap, 1.01325 BAR represents atmospheric pressure.

Swapping and legalizing motor swaps like this K20 can be difficult


The stock MAP sensor found in your Honda or Acura is usually mounted on the throttle body or the firewall. If you own a OBDII vehicle, chances are this unit is mounted to your throttle body. Learning how to service your MAP sensor is easy, making things like MAP bypass or MAP clamps installs a breeze.

How To Service a B18 MAP sensor


However when you want to run more than 11 psi of boost, you’re going to encounter problems. Specifically check engine lights for MAP sensor out of range, or something similar. You can of course get by with things like the Super AFC -40 hack for turbo Hondas, but the right way to do it is learning how to install a 3 BAR MAP Sensor.

Today we’ll be showing you just how to do that in any turbo Honda, or any vehicle for that matter. We’ll be using a universal Bosch MAP sensor part number 0 281 002 845. Similar to our universal Bosch Igniter How To, this article will show you how to install a 3 BAR MAP Sensor without the added cost of an adapter harness.

If you are learning how to install a 3 BAR MAP Sensor for your turbo Honda, you will also need the Bosch pigtail part number 1 928 403 736.

This Bosch MAP sensor is also a bolt on for many applications, like the Saturn Sky and Pontiac Solstice, making it a good upgrade option.

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What are the benefits to installing a 3 BAR MAP sensor?


You could conceivably run up to 28.5 PSI by installing a Bosch MAP sensor such as the one in our DIY How To Guide. There is no more fear of MAP sensor overrun and the accompanying limp mode and check engine light.

How To Dyno Tune your Turbo Honda


Be aware however that the open deck nature of your Honda stock block is not designed to handle such pressures. While you can get by for a while, you are only playing with fire without the proper supporting engine modifications.


What are the drawbacks to installing a 3 BAR MAP sensor?


You will require a chipped ECU or equivalent to correct the MAP sensor type in your Honda ECU. This entails either opening your stock ECU and installing a ZIF socket for an Electrically Erasable Programmable Read-Only Memory (EEPROM) chip that you can edit using a ROM Editor such as Hondata, Chrome or Neptune.

How To Chip a Honda ECU


This can be done through a P28 or P72 ECU that’s been chipped. Learn more about chipping your Honda ECU for turbo here, as well as our guide on tuning VTEC.

How to install a 3 BAR MAP sensor


Let’s begin by taking a look at our Bosch MAP sensor facing towards the connector. There’s four pins here and if you happen to have an older 3 pin 3 BAR MAP sensor, check our guide here. This particular unit has a built in IAT, which can be used if your management allows this input type.


The wiring for this Bosch MAP sensor pinout is shown above, and you will begin by wiring in the low reference ground signal. This is typically the green wire with white stripe on a B series. On a K series it’s a green wire with white stripe, and this connects to PIN 1 of your Bosch unit.

The next wire you’ll be teeing into the Bosch connector is the switched 5 volt. This wire provides 5 volts to the sensor with the key set to the “ON” position. This sensor power wire is yellow with a red stripe in the typical Honda colors. For both B and K series this wire is the same color code.

How To Test a MAP Sensor


The final part of our how to install a 3 BAR MAP sensor DIY guide is the MAP signal wire. Make sure you are leaving this wire last, as you’ll want to measure the output from your MAP sensor to test it.

This wire is white on most B series and D series engines, and will be green with a red stripe on the later K series engines. Using a multimeter you will also want to check the voltage range of this Bosch MAP sensor to finalize our how to install a 3 BAR MAP sensor guide.

With an operating range that peaks at 4.75 volts and excellent response time, this Bosch MAP sensor will be a great addition to your turbo project. Have any questions about our how to install a 3 BAR MAP sensor DIY guide? Leave them for us below!