Haltech E6M - Manual (Page 67)

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When the E6H/E6M is powered, it will run a small test to determine the barometric pressure.
As you have read earlier, the ECU switches the fuel pump on at start up (fuel pump prime). If
the engine is not started, the fuel pump will be switched off. At this time, the ECU also reads
the MAP Sensor. If the engine is not running, the MAP sensor will indicate the prevailing
barometric pressure. The ECU remembers this pressure and uses it to perform a barometric
correction on the fuel delivery.
If at start up the engine is cranked before the fuel pump prime has finished the ECU cannot
read the barometric pressure from the MAP sensor as the engine will be applying a vacuum to
it. In this case, the E6H/E6M will use the pressure value as set in Method 3. If you have not
adjusted it from factory settings, this will be 1013 mBars. To complete Method 2 follow these
steps:
1. Firstly set the Barometric Lock in the Fuel Set-up page to “disabled”.
2. Make sure the throttle position sensor is properly calibrated. It must exceed 96%
throttle for this to work. Also make sure that the MAP Sensor is set correctly in the
Identification.
3. Switch the ignition off.
4. Apply full throttle.
5. Switch the ignition on but DO NOT crank the engine.
6. Wait till the fuel pump prime finishes (about 5 seconds) then release the throttle.
The current barometric pressure as read by the MAP Sensor will be programmed
into the ECU’s memory.
It is not necessary or advisable to perform this reset regularly. It should only be done if
the vehicle’s regular place of garage is moved or if problems are suspected in the barometric
correction. For example, if an engine is tuned at sea level but is intended to be used mainly at
a higher altitude, then the reset should be performed once it reaches its new regular location.
After that, the automatic reading done at start up will be sufficient for the E6H/E6M to apply
barometric compensation and Method 2 is complete.
Method 3
Method 3 is the most complicated from of compensation since it allows continuous
barometric pressure readings to be taken by which fuel injection times can be adjusted. This
can only be done using an external MAP sensor (1 Bar) left open to the atmosphere to provide
barometric pressure readings.
To setup barometric compensation make sure that the Barometric Lock has been disabled in
the Fuel Set-up page. Go to the Input/Output page. Select the “Spare Input Function” field
and change it to “Baro. Sensor”. When you press enter, a field will appear below that contains
“external”. This field cannot be changed but indicates that an external MAP sensor (1 Bar)
must be used to measure atmospheric pressure in order to perform barometric compensation.
If this setup is used the external MAP sensor must be connected to the spare A/D