How to test MAP sensor?
 

I'm normally in the 2nd gen tech but I got a used FD MAP sensor to use with my AP Power FC for the FC. I think the MAP sensor is not working correctly since it made no difference whether it was plugged in or not. The commander read a value of -250mmhg at idle while my boost gauge read -400mmhg. I tried searching but nothing useful came up.

Is there a test I can do with a multimeter to check the MAP sensor without it installed in the car? If not is there a test I can do with it installed with the PFC?

bump for a good friend

93 workshop manual F-181

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| C-B-A |


Pressure Sensor
Inspection
1. Warm up engine to normal operating temp and run it at idle.
2. Turn all electrical load off.
3. Connect voltemeter between the pressure sensor terminal A and B and verify the voltage is within specification.

Voltage: 1.3-1.6v

4. Disconnect vacuum tube and plug the vacuum tube and verify the voltafe is within specification.

Voltage: 2.38-2.78v

5. Connect a vacuum pump to the pressure sensor.
6. Apply vacuum and measure the voltage of the pressure sensor.

Vacuum \ Voltage
-66 kPa (-500 mmHg. – 19.7 inHg) \ 1.25-1.55V
0 kPa (0 mmHg. 0 inHg) \ 2.38-2.78V
98.7 kPa (740 mmHg. 29.1 inHg) \ 4.35-4.65V

7. If not as specified, replace the pressure sensor.
8. Cancel the memory of malfunctions by disconnecting the negative battery cable for at least 20 seconds and depress brake pedal.
9. Reconnect the negative battery cable.

scratchjunkie,

That last 29.1" Hg is positive, so that would be about 14.3 psi pressure (boost), correct?

it looks about so. i copied the manual word for word. hope it helps you out sometime down the road.

scratchjunkie,

It did help, and thanks. My numbers were 1.18V @ 20" Hg vacuum, 2.68V @ atmospheric (sea level), and 4.58V @ 14.5 psi. Unfortunately, my idle vacuum is only about 10" and the MAP voltage confirms that, at 1.63 - 1.66V. Can't hear any hissing; don't know where the leak is. (Runs great off-idle, though.)

Thanks Wes!

"im not"

nice to see the link still works .. lol