Map sensor Q

[Pettersen]

My car is a 86 with 88 T2 engine.

Am i right in thinking this is the Map sensor and FCD?
So shouldn't the vacum pipe be connected to something after the turbo, and not just hang there blocked off?

[FRED]

In your hand is a NON TURBO boost sensor (Mazdas words from the FSM) or if you will the pressure sensor. Ain't no MAP sensor.

It should be seeing vacuum from the intake manifold.

The NON TURBO pressure sensor in your hand will give a false reading to the ECU and the idle will be a bit crummy because of that.

Disconnected from a source of vacuum that non turbo sensor will send to the ECU a voltage close to what is fuel cut i.e. 3.65vdc is fuel cut on a stk car. The FCD connected to it is preventing the ECU your using from going into fuel cut.

That sensor being disconnected is outputting just what the FSM says. See JPG below and the figure for pin 2B on the ECU of a stk NON TURBO (remember that 327 in your hand is non turbo).

The second jpg shows what a TURBO sensor would output under the same conditions i.e. vacuum hose off the sensor. Quite a difference in output, right?

Get a N318 sensor for your series four Turbo car.

[NoDOHC]

The common terminology for the pressure sensor is MAP sensor (Manifold Absolute Pressure). So the 'boost' sensor can be called a MAP sensor if you like.

You should have the correct boost sensor and have it connected, as the ECU uses it to determine ignition timing. You will get awful fuel economy without the correct boost sensor.