SM4 Manual
by
MRM-Racing
V3.0
13
Sensor and Device Pin Outs
Manifold Absolute Pressure Sensor
Autronic use a built in high quality map sensor with a maximum rating of 3.4 bar gauge or
4.4 bar Absolute pressure.
The MAP sensor is used to convert the manifold pressure to a electrical signal for the
ECU to use. The ECU displays the value in absolute pressure, thus its calibration is not
affected by change in barometric pressure. The vacuum/pressure, is proportional to the
load under which the engine is operating, and the ECU uses this as a load reference.
This is only the case when using Baro&Map, and not setup as Baro&TPS. See manual
under
Software basic setup.
a. Secure the hose with cable clamps or nylon ties. Use a vacuum connector where
there are no other accessories which will use up the vacuum like boost valves,
dump valves. If there is no empty connector it can share with the fuel regulator or
boost gauge. Make sure the point of connection will not cause fuel to get into the
hose and run down into the map sensor.
The SM4 can use a separate MAP sensor connected to analog 2-3 input (pin 38).
Coolant Temperature Sensor
The coolant temperature is used by the Autronic to determine warm up corrections and
adjust fuel mixtures. The coolant temperature sensor is a Bosch standard type of sensor
and some engines may already have provision for this type of sensor.
The coolant temperature sensor is designed to screw into a threaded hole and protrude
into the engine coolant stream. For air-cooled engines, the sensor can be embedded
directly into the engine block or used to sense oil temperature.
Locate a suitable position on the engine which will allow the hole and thread to be
machined, and which gives access to the coolant stream. The sensor should be mounted
after the engine and before the thermostat in the coolant circuit. Since most engines have
existing temperature sensor holes, it is often possible to mount the Bosch sensor in one
of these holes.
A thread adaptor is sometimes necessary. In some engines only one temperature sensor
hole exists and is used for the dashboard gauge sender. It is usually possible to install a
tee-piece to allow both the dashboard sender and the Bosch sensor to share access to
the same threaded hole.
If it is necessary to drain the coolant from the vehicle to fit the temperature sensor then
the factory manual for the engine should be consulted for the correct procedure to restore
the coolant and purge the cooling system of air.
Note
If setup as BARO&TPS, the internal map sensor should be unconnected.
This type of mapping is only for naturally aspirated engines and not recommended in
most cases. Use Baro&Map and set fuel table axis to TPS.
