Turbo Dodge 3 BAR MAP Sensor Wiring

The Chrysler "MAP" or Manifold Absolute Pressure sensor generates a variable signal voltage proportional to manifold (absolute) pressure, (not a variable frequency signal). The typical signal voltage of such a MAP sensor, generates ranges 0.5 volt DC at lowest pressure (vacuum) to just under 4.9 vDC at maximum (boost) pressures.

The 3-Bar MAP sensor can measure boost levels up to 28 PSI and replaces the standard Mopar Turbo I/II 2-bar MAP (14-15 PSI) sensor. The stock Normally Aspirated TBI uses a 1-bar MAP for its required range of 30 - 0 inches Hg vacuum.

Regardless of whether 1, 2 or 3-Bar MAP sensors are used, each range of MAP sensor still generates a signal between 0.5 to 4.9 vDC, depending on engine load. On a stock Chrysler 1990-91 SBEC the ECM monitors the 2-BAR MAP voltage for over-boost shutdown.  Safe, rapid, engine shutdown automatically occurs (via the ASD relay) whenever manifold boost pressure exceeds the factory-programmed set point within the SBEC. This occurs roughly somewhere around 4.74 vDC (MAP sensor signal output) or approximately 13 - 14 psi relative manifold pressure (Mopar factory calibrations vary by year and turbo/drivetrain configuration).If you want to run additional boost over the 2 BAR MAP ceiling of 14.7psi, you will need to install a 3 BAR MAP sensor and incorporate a custom calibration into your turbo Dodge automobiles engine management system.  You can not simply install a 3 BAR MAP sensor w/o also installing a 3 BAR calibration because the voltage produced by the MAP sensor ( a strain sensor basically) is totally different from the 2 and 3 BAR sensors.

For example...from the chart below, notive that the voltage reading for a 2 BAR MAP sensor at 15 psi (14.7 actually) is going to be approximately 5 Volts, which is the maximum signal source voltage for a common MAP sensor. But look at the voltage reading for the 3 BAR MAP signal at 15 psi, it will be only 3.4 volts. So if you are running a 2 BAR calibration, the computer will be seeing 3.4 volts and it will have been programmed to believe that you are actually only at 5 psi! So you will be running very very lean.  So you can’t mix and match 2/3 BAR MAP seensors with 2/3 BAR calibrations.

GM's AC-Delco division has a 3-Bar MAP sensor that was used on the 1989 Turbo Trans AM 3.8L V6. It is P/N  1#213-101 (1#1604-0749). This sensor must be used in conjunction with an intercooler, larger injectors, and a custom calibration, and a custom calibration such as FWD Performance Stage 5 SBEC. The custom SBEC calibration achieves higher than 2-bar ECM (wastegate) controller boost levels without resorting to 4.7 vDC zener diodes or adjustable bleed valves to "trick" the EMC.

When looking at the GM 3-Bar MAP sensor with the vacuum port facing you (front, as shown below), the three connectors are from left to right, "A, B, and C."

This sensor can commonly be found on Amazon or eBay and sold with the needed pigtail.  The keys incorporated into the pigtail from your turbo Dodge MAP pigtail will be different and you will either need to modify your existing pigtail by notching it or simply replace your original pigtail with one that fits the 3 BAR MAP sensor connection.

3 BAR MAP SOLD WITH PIGTAIL

ORIGINAL MAP PIGTAIL CAN BE NOTCHED AS NEEDED

Once you have selected your 3 BAR MAP sensor, wire it to your turbo Dodge using the following wiring guide. The chart indicates an SBEC engine controller however, other cars (earlier) wiring should be similar at the MAP sensor.