The guy I bought my van from says that the MAP sensor on 1990 Aerostars doesn’t need a vacuum line connected to it, and at this time there is none. Is this right?
If not, how can I find the line that is supposed to be connected to the MAP sensor?

 

JasonL,

If you're refering to the MAF (Mass Airflow sensor), it does not have a vacuum line. To my limited knowledge, none do.

Ron

 

No, EEC cars using MAF sensors will not use the MAP sensor. The MAP side of the dual pressure sensor will usually be plugged up. The atmospheric side of the sensor will be vented to...the atmosphere.

 

The MAP sensor is the Manifold Air Perssure sensor, you can find it on the drivers side of the fire-wall. I would imagine that it should have a vacuum line running to the intake manifold somewere, but I cant seem to find out any info about it.

 

Up until recently, the MAP sensor was a dual-pressure sensor. The MAP side was used by EEC cars that used the speed-density algorithm to determine the mass of the air entering the engine. With the switch over to mass-airflow (MAF) sensors, that was no longer necessary. So the MAP side of the dual sensor is usually plugged up, and its signal is not used.

The other side of the dual sensor is for sensing atmospherric pressure, so it is usually vented to the atmosphere. The EEC still needs this information.