VEMS v3 ECU User manual

12/16/2012
Installation Instructions and Setup Guide | Jason Russell

2
Table of Contents
Initial Information ........................................................................................................................................ 4
Legal isclaimer ....................................................................................................................................... 4
Planning Guide ......................................................................................................................................... 4
Getting Started ............................................................................................................................................ 5
Power up on the bench ............................................................................................................................ 5
Grounds ................................................................................................................................................... 5
Power Grounds .................................................................................................................................. 5
Sensor Ground ................................................................................................................................... 6
+12V Supply ............................................................................................................................................. 6
Connecting serial port .............................................................................................................................. 7
Connect essential sensors ............................................................................................................................ 8
Crank Trigger ............................................................................................................................................ 8
Connecting the primary trigger (Crank) ................................................................................................... 8
Configuring the crank trigger ................................................................................................................... 9
Connecting the Secondary Trigger (Cam) ................................................................................................. 9
Configuring the Secondary Trigger (Cam) .............................................................................................. 10
Temperature Sensors ............................................................................................................................. 10
IAT – Inlet Air Temperature .............................................................................................................. 10
CLT – Coolant Temperature .............................................................................................................. 10
TPS – Throttle Position Sensor ............................................................................................................... 11
Configuring the TPS sensor ................................................................................................................... 11
Secondary Sensors ..................................................................................................................................... 12
WBO2 ..................................................................................................................................................... 12
EGT ........................................................................................................................................................ 12
Knock .................................................................................................................................................... 13
Primary Outputs ........................................................................................................................................ 14
Connecting Ignition Components .......................................................................................................... 14
Example coil connections ................................................................................................................ 16

3
Single coil ......................................................................................................................................... 16
Coil pack .......................................................................................................................................... 17
Coil on plug (COP) ............................................................................................................................ 18
Using the Stepper Motor river to control Ignition ............................................................................... 18
Ignition Setup ......................................................................................................................................... 19
Index engine .......................................................................................................................................... 20
Injector Model ....................................................................................................................................... 21
Injector Outputs ..................................................................................................................................... 22
Secondary Outputs ................................................................................................................................ 22
Inputs ......................................................................................................................................................... 23
Misc Outputs ............................................................................................................................................. 23
List of Authorized Resellers ........................................................................................................................ 24
Appendix .................................................................................................................................................... 25
Connector pinout ................................................................................................................................... 25

4
Initial Information
Legal Disclaimer
The authors, advisors, manufacturers, website maintainers or anyone involved in shipping or
support are NOT responsible for consequences - even if it's proven that any injury, damage or
inconvenience is directly caused by their advice.
No applicability of the hardware, firmware, other software, instructions, or documentation for a
particular purpose is claimed.
ll installers, diy-ers, and users are responsible for testing, installing, programming and using
their units.
You understand that modifications are suitable to ruin your engine. Modifications usually
invalidate any emission related certification, and most often invalidates the license to use the
equipment (eg. car, snowmobile) at all. For off-road use only.
You understand that like any electronic or mechanical equipment, they can fail. Failing
equipment in a vehicle can be fatal.
You are responsible for compliance with the laws of your jurisdiction.
If any provision of these Terms and Conditions is found to be invalid by any court having
competent jurisdiction, the invalidity of such provision shall not affect the validity of the
remaining provisions of these Terms and Conditions, which shall remain in full force and effect.
No waiver of any of these Terms and Conditions shall be deemed a further or continuing waiver
of such term or condition or any other term or condition.
In short, we can not cover every conceivable scenario. Please be aware of the consequences and plan
accordingly. Be safe!
Planning Guide
Things you need to know before ordering an ECU:
•Crank trigger type
•Trigger wheel
•Cam trigger type (if applicable)
•Number of Cylinders
•Number of coils
•Type of coil (logic level or high current)
•Number of fuel injectors
•Type of fuel injectors (high impedance or low impedance)

5
•Type and value of temperature sensors
•Any accessories or options you may want
•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:
•connect Sensor GN (EC36 pin 26) and the 4 Power GN s with short (preferably 10..15cm, max
20..30cm from EC36), strong (preferably 0.75mm2 or stronger) wires.
oPower 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.
•Keep the Power Ground connection (EC36 pin26, 5,21,22,32) pins to the Common Ground point
short max 0.1 .. 0.3m,
ouse 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.
oconnect the ground of the sensors to the Common Ground point or to the sensor ground
branch, that is EC36pin26.
oConnect Power Grounds to the Common Ground point, or anywhere you like (except the
sensor-ground branch)
•Failure to connect Sensor Ground and Power Ground will damage your VEMS. Even on the test
bench !

6
Power Grounds
lso called as "GND5" in some documents
•EC36-pin5 to Common Ground
•EC36-pin21 to Common Ground
•EC36-pin32 to Common Ground
•EC36-pin22 to Common Ground
Sensor Ground
•EC36-pin26 to Common Ground. NOTE: Sensor Ground pin has many connections (CAS, TPS, IAT,
CLT ...) make provision for this in your wiring loom.
+12V Suppl
•EC36-pin25 3A Fused +12v supply
Note that if you have moved the battery to the rear of the car you may want to run separate wires for
the starter/alternator and for the cars electrical system to the battery. Otherwise the several meters long
cable will cause a significant voltage drop during cranking that will cause the ECU to reset when the
battery starts to run low. This may prevent the car from starting even if the engine cranks over.
Once you have connected and checked the continuity of ground you can connect your VEMS
unit to the EC36 plug and apply the power supply. There is little point in connecting power until
the serial connector is added though.

7
Connect the serial port
Connecting serial port
To allow the connection of the VEMS unit to your PC a serial port plug must be connected as
follows.
•EC18-pin14 to SUB9-pin3
•EC18-pin15 to SUB9-pin2
•EC36-pin26 to SUB9-pin5 (GN ).
Start VemsTune and test connectivit
If you don't already have VemsTune, you can download it from here: http://www.vems.hu/vt
Always stay up to date with VemsTune. This is especially important when updating the firmware on the
ECU. Older VemsTune releases may not understand and properly handle the newer firmwares.

8
Start VemsTune, select the COM port that is connected to the ECU. You may notice that a TCP connection
is also supported if you have a TCP serial adapter.
Connect essential sensors
Crank Trigger
The trigger is the engine management system's most fundamental sensor, without one VEMS
cannot calculate engine speed or crank angle. If you are connecting VEMS to an engine that has
an existing engine management system, if not then a triggering method will need to be put in
place.
The simplest type of trigger is to use the existing distributor to provide a pulse for each cylinder.
This type of trigger is more than adequate for driving ignition through a distributor and batch fire
injection.
Connecting the primar trigger (Crank)
Magnetic sensor / Variable reluctance (VR)
Mechanical considerations
If you are fitting a crank sensor to an engine it is advisable to use a hall sensor rather than
a VR sensor. They are more forgiving to wheel design and noise. Generally, VR sensors
should be used in applications utilizing factory sensors.
The VR sensing circuitry is very sensitive to electrical noise, shielded cable (coax) must be used
and good grounding is vital.
•EC36-pin27 VR+ Note that some other ECUs trigger on positive-going edge so their schematic
might mark the + and GN swapped: so don't blindly follow naming from autodata pinout or
some schematic, keep in mind that + and - might need to be swapped. Measure to be sure:
InputTrigger/TriggerLog
•EC36-pin26 VR-
Shielding should be grounded to engine block close to the VR Sensor.
Hall Sensor

9
VEMS is available configured for Hall sensors, these are more noise tolerant and require a +5V
(or sometimes +12V for some sensors) supply.
•EC36-pin27 Hall signal
•EC36-pin26 Ground
•EC36-pin28 +5V
Configuring the crank trigger
Crank Trigger configuration can be accessed from the Base Setup menu in the Primary Trigger Settings
option. Trigger Edge should normally be rising for VR, falling for Hall. A hall sensor may be configured for
rising if the trigger edge needs to be moved the width of a tooth, but this is generally not needed. Select
the trigger type. Missing tooth is most common and includes 36-1, 60-2, and other common wheels with
missing teeth. If the wheel doesn't have any missing teeth, that is coil-type. Missing tooth type should be
n-1 if there is one missing tooth on the wheel, and n-2 if there are two missing teeth on the wheel.
Number of teeth on the wheel is the number of remaining teeth. 58 for a 60-2 wheel for example. There
are very useful defaults at the bottom of the window to set up your trigger wheel. T C after the trigger
needs to be measured and set with a timing light. Use the Tools → Ignition Lock menu item to set your
timing at 0.25 degrees and crank the engine and verify cylinder 1 fires at T C. Adjust the T C after the
trigger until correct. You may need to change the First Trigger Tooth if the T C after the trigger value gets
below 40 degrees or above 100 degres. 60 degrees is a good value to aim for. Pressing F1 on the Primary
Trigger Settings window, or any window in VemsTune, will give you some detailed help with more
specific information.
Connecting the Secondar Trigger (Cam)
VR type

10
Hall Effect Type
Configuring the Secondar Trigger (Cam)
The secondary trigger is most often used for cam sync. This can be configured on the Base Setup menu
under the Secondary Trigger Settings item. Mode is either isabled or Cam-Sync except under special
circumstances. Use rising edge for VR sensor. Either edge can be used for a Hall sensor, but typically
falling is used. Event at Bad Trigger Position is the last common item to configure. It is recommended to
set it to Just Show. You can have it disable injection if you wish, but it is not recommended.
Temperature Sensors
VEMS uses two temperature sensors: Inlet Air Temperature which is used in speed/density systems to
calculate the amount of fuel required. And Coolant Temperature which is used to meter the required amount
of warm up fuel enrichment.