Ford manifold absolute pressure sensor
Last Updated on July 23, 2024 by Mutiara
To prevent the replacement of good components, be aware that the following non-EEC areas may be at fault:
- Unusually high/low barometric pressure.
- Kinked or obstructed vacuum lines (MAP).
- Basic engine (valves, vacuum leaks, timing, EGR valve, etc.).
The Manifold Absolute Pressure (MAP) sensor operates as a piezoelectric (pressure-sensing) disc. However, rather than generating a voltage, its output is a frequency change. The sensor changes frequency relative to intake manifold vacuum. The sensor frequency increases as vacuum increases. The MAP sensor allows the PCM to determine what the engine load is. Its signal affects air/fuel ratio, ignition timing, EGR flow and altitude compensation.
Manifold Vacuum | MAP Frequency | |
---|---|---|
inHg | kPa | Hz |
0 | 0 | 159 |
3 | 10.2 | 150 |
5 | 16.2 | 146 |
6 | 20.3 | 141 |
8 | 25.7 | 134 |
9 | 30.5 | 133 |
11 | 36.7 | 126 |
12 | 40.6 | 125 |
13 | 45.4 | 121 |
14 | 47.2 | 119 |
15 | 50.8 | 117 |
16 | 54.0 | 114 |
17 | 57.0 | 111 |
18 | 61.0 | 109 |
19 | 76.3 | 107 |
20 | 70.0 | 104 |
21 | 71.1 | 102 |
23 | 78.1 | 97 |
24 | 81.3 | 95 |
27 | 91.5 | 88 |
30 | 101.6 | 80 |
29.92 inHg= Sea Level, 100 kPa = Sea Level, 5280 ft = 1 mile, 14.7 PSI= Sea Level
Article & images courtesy of fordfuelinjection.com.