5
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Type and value of temperature sensors
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Any accessories or options you may want
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MAP sensor range (2.5 bar, 3bar, 4bar, or external)
Order info, options, ignition outputs, EGT, Knock,
Getting Started
Initial Power up
Connect all the grounds
Grounds
From the outset it cannot be stressed enough just how important grounding is. 95% of all noise
issues are due to poor grounding.
Grounds need to be connected with a clean connection and thick wire, and near the ECU. There
are two branches so the fluctuation of power signals do not interfere with the measured signals
(most importantly: the trigger):
Power Ground handles the noisy and high currents generated by driving injectors, coils and
solenoids.
Sensor Ground handles 0 to 5v signals from crank, throttle and temperature sensors. VR-trigger
sensor at low RPM (cranking) is the most sensitive to noise.
The GROUND rules:
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connect Sensor GND (EC36 pin 26) and the 4 Power GNDs with short (preferably 10..15cm, max
20..30cm from EC36), strong (preferably 0.75mm2 or stronger) wires.
o
Power Grounds & Sensor Grounds MUST terminate at the same point - Common
Ground. Run the wires into a single ring crimp so that there is no chance of one ground
coming free.
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Keep the Power Ground connection (EC36 pin26, 5,21,22,32) pins to the Common Ground point
short max 0.1 .. 0.3m,
o
use strong wires. Preferably all 5 wires should be 0.75mm2 or stronger. Some
installations (particularly with no PWM-ing) could tolerate somewhat longer wires, but
why risk it ? (ground problems are like ghosts, very hard to track down). The length of
wire(s) from this common ground point to battery / chassis can be longer (and usually
are long). Strong wires must be preferred (total 4mm2), and not longer than necessary.
But at least nowhere near as sensitive as the wires right at the ECU.
o
connect the ground of the sensors to the Common Ground point or to the sensor ground
branch, that is EC36pin26.
o
Connect Power Grounds to the Common Ground point, or anywhere you like (except the
sensor-ground branch)
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Failure to connect Sensor Ground and Power Ground will damage your VEMS. Even on the test
bench !
