Perfect Power XMS4A User manual

XMS4A
LetRipp II
Engine Management System
DIY MANUAL
Version 2.1

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PERFECT POWER XMS4A – Engine Management System DIY MANUAL V2.1
TableofContents: Pageno:
1. INTRODUCTION.................................................................................................1
2. PARTS SUPPLIED IN THE KIT...............................................................................1
3. WHY SHOULD YOU READ THIS MANUAL?...............................................................1
4. EXPLANATION OF XMS4 UNITS AVAILABLE............................................................2
5. TECHNICAL DETAILS ..........................................................................................3
5.1 FUEL INJECTION.............................................................................................3
5.2 IGNITION ......................................................................................................3
5.3 ACCELERATION ENRICHMENT...........................................................................4
5.4 INJECTOR/ENGINE PRIMING.............................................................................4
5.5 TRIGGER INPUTS............................................................................................4
5.6 BOOST CONTROL............................................................................................4
5.7 PRIME (FUEL).................................................................................................4
5.8 IDLE CONTROL...............................................................................................4
5.9 SETPOINT CONTROL .......................................................................................4
6. FEATURE EXPLANATION......................................................................................5
6.1 LAUNCH CONTROL..........................................................................................5
6.2 EXTERNAL SUPPLY TO SENSORS.......................................................................5
6.3 MAPS A / B ....................................................................................................5
6.4 CALIBRATION.................................................................................................5
6.5 FUEL INJECTION MAP......................................................................................5
6.6 IGNITION MAP ...............................................................................................5
6.7 COMPENSATION MAP ......................................................................................5
6.8 BOOST CONTROL............................................................................................6
6.9 SETPOINT......................................................................................................6
6.10 MAXIMUM RECORDINGS..................................................................................6
6.11 ONBOARD LOGGING (COMING SOON)...............................................................6
6.12 COMMUNICATION CONNECTION .......................................................................6
6.13 USB DRIVERS SETUP.......................................................................................7
7. COMPUTER REQUIREMENTS ................................................................................7
8. PIN OUTS OF XMS4A UNIT ..................................................................................8
8.1 XMS4A PIN-OUT TABLE....................................................................................8
8.1.1 XMS4A IGNITION PIN-OUT CONNECTOR (6 PIN)..............................................8
8.1.2 XMS 4A INJECTION PIN-OUT CONNECTOR (8 PIN) ...........................................8
8.1.3 XMS 4A AUXILIARY CONNECTOR (4 PIN) ........................................................9
8.1.4 XMS 4A MAIN CONNECTOR (22 PIN) ..............................................................9
9. ASSESSING YOUR CAR’S FUEL SYSTEM...............................................................10
9.1 IS YOUR CAR READY FOR FUEL INJECTION?.....................................................10
9.2 HOW TO MAKE YOUR CAR READY FOR FUEL INJECTION .....................................10
9.3 CONCLUSION...............................................................................................11
10. ASSESSING YOUR ENGINE ................................................................................11
10.1 COMPATIBLE TRIGGER WHEEL........................................................................11
10.2 CAMSHAFT SENSOR......................................................................................12
10.3 HOW TO INSTALL A COMPATIBLE WHEEL AND PICKUP SENSOR ..........................12
10.4 WHICH SENSORS ARE MISSING?....................................................................13
10.5 INJECTOR RESISTANCE .................................................................................13
10.6 MAKE SURE THE ENGINE HAS THE BASICS.......................................................14
10.7 CONCLUSION...............................................................................................14
11. WHERE TO FIT YOUR XMS4A?............................................................................14
11.1 SUITABLE PLACES ........................................................................................14
11.2 UNSUITABLE PLACES ....................................................................................15
11.3 CONCLUSION...............................................................................................15
12. WHERE TO FIT THE IGNITION AMPLIFIER? ..........................................................15
12.1 SUITABLE PLACES ........................................................................................15
12.2 UNSUITABLE PLACES ....................................................................................16
12.3 CONCLUSION...............................................................................................16
13. SCREENED CABLE............................................................................................16
13.1 WHAT IS A SCREENED CABLE? .......................................................................17

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13.2 WHY SHOULD I USE A SCREENED CABLE?........................................................17
13.3 WHAT SHOULD YOU USE A SCREENED CABLE ON? ............................................17
14. CRANK SIGNALS - WHAT DO THEY LOOK LIKE?....................................................17
14.1 POSITIVE EDGE............................................................................................17
14.2 NEGATIVE EDGE...........................................................................................18
14.3 MAGNETIC...................................................................................................18
14.4 DIGITAL/HALL EFFECT...................................................................................18
15. TYPICAL SENSORS USED AND HOW TO WIRE THEM..............................................18
15.1 AMP............................................................................................................19
15.2 ENGINE TEMP...............................................................................................19
15.3 AIR TEMP ....................................................................................................20
15.4 THROTTLE POSITION ....................................................................................21
15.5 CRANK ANGLE SENSOR .................................................................................21
15.6 CAMSHAFT SENSOR......................................................................................22
15.7 CONCLUSION...............................................................................................22
16. TYPICAL DEVICES DRIVEN BY THE XMS4A...........................................................23
16.1 BOOST SOLENOID ........................................................................................23
16.2 FUEL PUMP RELAY.........................................................................................23
16.3 FAN RELAY...................................................................................................24
16.4 2 WIRE IDLE CONTROL MOTOR.......................................................................24
16.5 SHIFT LIGHTS..............................................................................................25
16.6 REV COUNTER..............................................................................................25
16.7 INJECTORS..................................................................................................25
16.8 IGNITION AMPLIFIERS...................................................................................26
17. IDLE CONTROL – IN MORE DETAIL .....................................................................27
17.1 TWO WIRE IDLE – SOFTWARE SETUP ..............................................................27
17.1.1 F3 – TWO WIRE IDLE FOR XMS4A.............................................................28
17.1.2 SHIFT F2 – SYSTEM DEF .........................................................................28
17.1.3 IDLE RPM TARGET..................................................................................29
17.1.4 SHIFT/F11 – 2WIRE IDLE ........................................................................29
17.1.5 SETTING UP THE IDLE ............................................................................30
18. DWELL TIME....................................................................................................30
18.1 WHAT IS DWELL? .........................................................................................30
18.2 CAN IT DAMAGE YOUR COIL? .........................................................................30
18.3 DWELL SETUP VIA SOFTWARE........................................................................31
19. SETTING UP PARAMETERS.................................................................................32
20. SYSTEM DEFINITION........................................................................................33
21. SET POINTS ....................................................................................................34
21.1 USES ..........................................................................................................34
21.2 WIRING.......................................................................................................34
21.3 SETUP VIA SOFTWARE ..................................................................................35
22. CALIBRATION OF SENSORS...............................................................................35
22.1 AMP............................................................................................................36
22.2 ENGINE TEMP...............................................................................................36
22.3 AIR TEMP ....................................................................................................37
22.4 THROTTLE POSITION ....................................................................................37
22.5 CONCLUSION...............................................................................................37
23. RPM...............................................................................................................38
23.1 SETUP AND CALIBRATION VIA SOFTWARE .......................................................38
23.2 LIMIT..........................................................................................................38
23.3 CONCLUSION...............................................................................................39
24. WHAT TO DO BEFORE TRYING TO START THE ENGINE ..........................................39
24.1 IGNITION SETUP WITH TIMING MARKS AND TIMING LIGHT................................39
24.2 IGNITION ADJUSTMENT VIA SOFTWARE ..........................................................40
25. TIME TO START THE ENGINE .............................................................................40
25.1 FIRST THINGS TO DO WHEN CRANKING THE ENGINE........................................40
25.2 FIRST THINGS TO DISABLE WHEN THE MOTOR IS RUNNING ..............................40
25.3 IDLE SETUP .................................................................................................41
25.4 FUEL SETUP WITH AMP..................................................................................41

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25.5 CONCLUSION...............................................................................................43
26. LOOK HERE IF IT DOESN’T START......................................................................43
26.1 POSSIBLE REASONS AND COMMON CHECKS ....................................................43
27. TUNING YOUR XMS4A FOR THE FIRST TIME.........................................................44
27.1 OPTIONS.....................................................................................................44
27.2 TOOLS NEEDED............................................................................................44
27.3 FUEL TUNING...............................................................................................44
CO MEASUREMENTS.........................................................................................44
4 GAS ANALYSER.............................................................................................45
27.4 IGNITION TUNING ........................................................................................47
28. COLD START MAP.............................................................................................48
29. ACCELERATION ENRICHMENT............................................................................49
30. SETTING THE BOOST CONTROL UP.....................................................................49
30.1 CLOSED LOOP..............................................................................................49
30.2 VIA PWM .....................................................................................................50
31. LAUNCH CONTROL ...........................................................................................50
31.1 USES ..........................................................................................................50
31.2 SETUP VIA SOFTWARE ..................................................................................51
31.3 CONCLUSION...............................................................................................51
32. TROUBLESHOOTING.........................................................................................51
32.1 FUEL...........................................................................................................51
32.2 PRESSURE...................................................................................................51
32.3 IGNITION ....................................................................................................51
32.4 SPARK PLUGS ..............................................................................................52
32.5 COIL...........................................................................................................52
32.6 TWO WIRE COIL...........................................................................................52
32.7 THREE WIRE COIL ........................................................................................52
32.8 FOUR WIRE COIL:.........................................................................................53
32.9 TRIGGER WHEEL ..........................................................................................53
32.10 TRIGGER SENSOR .....................................................................................53
32.11 ENGINE FAILURE, NO COMPRESSION...........................................................54
33. BASIC XMS4A-2A WIRING DIAGRAM...................................................................55
34. BASIC XMS4A-4A WIRING DIAGRAM...................................................................56
TableofFigures: Pageno:
FIGURE 1. FUEL SYSTEM LAYOUT.................................................................................10
FIGURE 2. ENLARGED VIEW OF SURGE TANK.................................................................11
FIGURE 3. CRANK PULLEY...........................................................................................12
FIGURE 4. 60 – 2 TOOTH WHEEL SETUP........................................................................13
FIGURE 5. TYPICAL “UNDER THE DASHBOARD” INSTALLATION ........................................14
FIGURE 6. 4 WIRE PLUS SCREEN FOIL..........................................................................17
FIGURE 7. WIRING OF PERFECT POWER AMP SENSOR ....................................................19
FIGURE 8. WIRING OF PERFECT POWER ENGINE TEMP SENSOR .......................................20
FIGURE 9. WIRING OF PERFECT POWER AIR TEMP SENSOR.............................................20
FIGURE 10. WIRING OF THROTTLE POSITION SENSOR ...................................................21
FIGURE 11. WIRING OF MAGNETIC ..............................................................................21
FIGURE 12. WIRING OF HALL EFFECT...........................................................................22

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PERFECT POWER XMS4A – Engine Management System DIY MANUAL V2.1
1. INTRODUCTION
Congratulations on the purchase of your first XMS4A engine management system. This
product is a leader in aftermarket engine management systems and it uses the latest 16bit
technology.
The XMS4A series is a result of many years of development. What started in 1986 as a hobby
has turned into a company that thrives on innovation and performance. With the latest
technology backing our products and new features continuously being added the XMS4A
surpasses any price or performance comparison.
The XMS4A uses “LETRIPP TECHNOLOGY” and thus can be tuned by the LETRIPP WINDOWS
TUNING SOFTWARE. The new XMS4A product range will undergo extensive modifications and
upgrading over the next few years. Please make sure you have the latest software version
which can be downloaded from our website www.perfectpower.com.
2. PARTS SUPPLIED IN THE KIT
For your XMS4A to function correctly it is essential to confirm that all the necessary items
have been supplied.
The standard items supplied in the XMS4A kit include:
1 x XMS4A unit
1 x XMS4A harness
1 x Software CD that includes manuals and USB drivers.
1 x USB tuning cable
If you don’t have all of the above items please contact us immediately either via
www.perfectpower.com or [email protected].
The use of a suitable dual channel ignition amplifier is required for all installations of the
XMS4A product. We do supply a product with the required specifications called the Blue-Fire,
however you are welcome to make use of a different manufacturer (as long as the specs are
the same).
3. WHY SHOULD YOU READ THIS MANUAL?
The XMS4A standalone engine management system has a lot of features and even more wires,
which can be quite daunting. However this manual will guide you through the different stages
of installing the unit and finally tuning the engine.
To unlock or use the XMS4A to its full potential this manual MUST be read – even if you are a
novice or a professional at installing systems. If this is your first time installing an XMS4A,
then the manual will explain how to do things and things to avoid. Our goal is to get the
installation up and running with the least amount of time and problems as possible. As with
most manuals you may be reading this one because you are stuck or something isn’t working
and you need assistance.

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4. EXPLANATION OF XMS4 UNITS AVAILABLE
There are 6 different versions of the XMS4 unit available, and in this section we explain each
version available.
Hardware
Type Part Number Details
A XMS4A-2A
2 Injection and Ignition Outputs, 4 Cylinder Batch Injection with
installed AMP sensor
A XMS4A-4A
4 Injection and Ignition Outputs, 4 Cylinder Sequential Injection.
4 Set points with installed AMP sensor.
B XMS4B-4A
4 Injection and Ignition Outputs, Wideband lambda controller. 4
Set points, with installed AMP sensor.
B XMS4B-8A
8 Injection and Ignition Outputs, Wideband lambda controller. 4
Set points, with installed AMP sensor.
C XMS4C-4A
4 Injection and Ignition Outputs, ETC, Wideband lambda
Controller. 8 Set points, with installed AMP sensor.
C XMS4C-8A
8 Injection and Ignition Outputs, ETC, Wideband lambda
Controller. 8 Set points, with installed AMP sensor.

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5. TECHNICAL DETAILS
The following features are that of an XMS4A.
5.1 FUEL INJECTION
•3-Ampere injector drives : 2, 4
•Injection : Batch, Sequential
•Injector trimming : Yes
•Main map sites : 384
•Manifold pressure map sites : 24
•Engine temperature map sites : 24
•Air Temperature map sites : 24
•Max duty cycle : 100%
•Peak and Hold : No
•Injection length resolution : 0.01Ms
Total injection length is calculated as follows:
+Mainmapentry
+ Air temperature entry
+ Engine temperature entry
+ Acceleration enrichment
+ AFR Short term loop adjustment
+ AFR Long term trim
+ Manifold pressure entry
+ Fuel range
Other fuel components:
+ Priming
+Idlecontrol
+ Set point control Soft/Hard fuel cut
5.2 IGNITION
Cylinders : 2, 3, 4, 6, 8
Ignition : Sequential: 2, 3, 4 Cylinders
Ignition outputs : 2, 4, 8
Directdrive :NO
Output polarity : Positive
Main map sites : 384
Manifold pressure map sites : 24
Engine temperature map sites : 24
Air temperature map sites : 24
Dwell length map sites : 24
Total ignition angle is calculated as follows:
+- Main map entry
+- Manifold pressure
+- Engine temperature entry
+- Air temperature entry
Other ignition components:
Launch control retard
Dwell

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5.3 ACCELERATION ENRICHMENT
Acceleration RPM Enrichmentmapsites: 24
Acceleration Air Temperature enrichment map sites: 24
Acceleration initial injection map sites: 24
5.4 INJECTOR/ENGINE PRIMING
Prime Engine temperature sites: 24
5.5 TRIGGER INPUTS
Balanced CRANK input YES
Balanced CAM input YES
Triggers on logic signal YES
User selectable CRANK polarity YES
User selectable CRANK trigger level YES
User selectable CAM trigger level YES
CAM on/off option YES
5.6 BOOST CONTROL
For Turbo waste gate control YES
PWM bleed Air temp. map sites 24
PWM sites for cruising 24
PWM sites for full power 24
Target boost map sites 24
PIDloopgain YES
5.7 PRIME (FUEL)
24 Map sites accessed by the engine temperature, allow extra fuel during starting.
5.8 IDLE CONTROL
Target RPM map sites via temperature 16
For 2 wire idle motors YES
PID control YES
Integration time adjust YES
Loop gain adjust YES
5.9 SETPOINT CONTROL
Number of set-point functions 16
Number of assigned relay outputs 4
Output drives 0.5A
High/Low limit setting YES
Soft fuel limit YES
Hard fuel cut YES
“OR”function YES
“AND” function YES
Map switching YES
Output short circuit protection YES
Over-temperature protection YES

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6. FEATURE EXPLANATION
6.1 LAUNCH CONTROL
The Launch Control is for turbo cars where “spooling up” of the turbo is required on the start
line. It is an extra switch input. The Launch Control is affected and works in the following way:
Proportional retard above a settable launch RPM limit. When the clutch is depressed (pushing
a switch) the ignition is retarded when a specified RPM is exceeded and advanced back to
normal when the clutch is released.
The Launch Control feature can also be used for “Flat-foot-shifting” in non-turbocharged
engines. This restricts the RPM to a specified level while the clutch is pressed and the
accelerator is pressed down.
6.2 EXTERNAL SUPPLY TO SENSORS
A separate +5 Volt output (pin 9 of 22) is available to power manifold pressure and TPS
sensors.
6.3 MAPS A / B
The XMS4A has two complete maps for all tuning data. Maps can be switched while driving.
The two maps can hold different tuning for weather, fuel grade or performance requirements.
The maps can be switched from a manual input, or automatically via the SETPOINT procedure
in the LetRipp Software.
6.4 CALIBRATION
All inputs can be calibrated to suit your existing sensors of your engine. Calibration is
performed for two reasons:
A) So that the XMS4A interprets the sensor readings correctly.
B) So that the Tuner (you) can read the data in engineering units (Bar/PSI,
Fahrenheit/Degree C, other).
6.5 FUEL INJECTION MAP
This map controls the fuel injection. The amount of fuel injected can be mapped on 384 sites
(main map) and the output of the three possible side maps can modify the main map value.
The entry is in counts, 100 counts = 1.00mS.
6.6 IGNITION MAP
This map controls the ignition. The ignition angle in degrees is from the 384 main map sites
and is further modified in the possible three side tables of 24 map sites each.
6.7 COMPENSATION MAP
This map contains various items:
•Acceleration enrichment
•Dwell time specification
•Priming
•Idle target control

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6.8 BOOST CONTROL
Boost Control is for turbo installations where the boost must be controlled:
•To avoid knocking on an engine, OR
•To avoid damaging a motor that is not designed for boost above a certain pressure, OR
•When the boost is increased at high RPM.
The boost level can be specified for each of the possible 24-RPM map sites. The XMS4A will
operate a “bleed” valve with the specified PWM values. The BOOST control loop can be
operated as an “open” loop by setting the required bleed PWM or as a “closed” loop PID
controller with target and gain adjustment.
NOTE: DO NOT use a solenoid with less than 13 ohm.
6.9 SETPOINT
The XMS4A has 4 set point outputs, which can be activated from 16 different signal sources.
This is for the implementation of fan control, gearshift lights, RPM limits, soft fuel cut and all
other small jobs around the engine and cockpit. All functions can be combined in a logical
AND/OR fashion, and polarity selection is possible.
6.10 MAXIMUM RECORDINGS
The units recorded are:
•Max RPM
•Max Engine temperature
•Max Air temperature
•Max Manifold pressure (AMP)
The maximum recordings can be retrieved and cleared by using a computer only.
6.11 ONBOARD LOGGING (COMING SOON)
All units have a very large memory for logging 64000 data points. This converts to:
•5 Data channels, 12800 recordings OR 8 Data channels, 8000 recordings.
The amount of channels can be stipulated. The recording frequency ranges from:
•200 records per second, 5ms TO 1 record per second, 1000ms
This means that 5 channel data can be recorded for 64 seconds at 5ms intervals, or for 213
minutes at 1 second intervals.
More to come later!
6.12 COMMUNICATION CONNECTION
All variations in the XMS4A product range have a USB 2.0 communication connector. It is best
to use the supplied cable to connect the XMS4A unit to your computer. If any communication
problems are encountered, (e.g. the PC hangs and must be restarted), then a “FERRITE”
interference eliminator must be used on the cable!
It is critical to follow the exact procedures for installing the USB drivers in the order indicated
in the Auto start on the CD supplied with the kit.

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6.13 USB DRIVERS SETUP
You will need to follow the step-by-step procedure to load the Windows Tuning Software and
USB Drivers, in order for the unit to function correctly. The USB Drivers and Software need to
be installed in a specific order. You must refer to the “LetRipp Software Manual” to follow
the correct procedure.
Once the software and USB drivers have been correctly installed, the unit will operate when
connected to the USB port via the USB cable. Thus the Computer will supply power to the unit.
Although all functions will work, the unit will not power external sensors.
NOTE: DO NOT ATTEMPT TO OPERATE THE XMS4A UNLESS THE USB INSTALLATION
PROCEDURE HAS BEEN FOLLOWED. FAILURE TO DO SO WILL RESULT IN THE NON-
OPERATION OF THE UNIT AND A LOT OF GRIEF TO CORRECT IT!
7. COMPUTER REQUIREMENTS
Intel 486 or higher, WINDOWS XP, USB Connection. At present, the LetRipp Software is NOT
Windows Vista compatible.

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8. PIN OUTS OF XMS4A UNIT
8.1 XMS4A PIN-OUT TABLE
8.1.1 XMS4A IGNITION PIN-OUT CONNECTOR (6 PIN)
Pin Signal Description
1 GND Ground, chassis
2 IGN#1 #1 Ignition pulse output, positive
3 N/C N/C
4 IGN#2 #2 Ignition pulse output, positive
5 IGN#3 #3 Ignition pulse output, positive
6 IGN#4 #4 Ignition pulse output, positive
NOTE: The XMS4A-2A has ignition outputs 1 and 2
8.1.2 XMS 4A INJECTION PIN-OUT CONNECTOR (8 PIN)
Pin Signal Description
1 N/C N/C
2 INJ#1 Injector #1 output, switched to ground
3 INJ#3 Injector #3 output, switched to ground
4 GND Power Ground, Chassis
5 N/C N/C
6 INJ#2 Injector #2 output, switched to ground
7 INJ#4 Injector #4 output, switched to ground
8 GND Power Ground, Chassis
NOTE: The XMS4A-2A only has injector outputs 1 and 2
512 3
4
61011
12
978
13141516171819202122 5
12
3
4
678
5
12
3
4
6
12
3
4
XMS 4 A
Ignition
Main Connector
Auxiliary
PC
Injection

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8.1.3 XMS 4A AUXILIARY CONNECTOR (4 PIN)
Pin Signal Description
1 W1 Wire #1 output, switched to ground
2 W2 Wire #2 output, switched to ground
3 W3 Wire #3output, switched to ground
4 W4 Wire #4 output, switched to ground
8.1.4 XMS 4A MAIN CONNECTOR (22 PIN)
Pin Signal Description
1 MAP SW Map Switch Input, Open=high=A
2 CB 1 -
3 GND Signal Ground
4 CB 2 -
5 Rev Counter Rev counter driver
6 AMPIN 0-5V input signal
7 TPSIN 0-5V input signal
8 N/C Not used
9 +5volts EXT +5, 0.1A Output for TPS and AMP
10 +5volt pull up
11 GND
12 N/C Not used
13 Cb 1 +
14 GND
15 Cb 2 +
16 N/C Not used
17 AIRT IN 0-5V input, internal pullup 2k2 to +5
18 ENGT IN 0-5V input, internal pullup 2k2 to +5
19 N/C Not used
20 Launch Switch SWITCH input, normal high (open)
21 +5volt pull up
22 + SUPPLY Switched Battery Supply
Refer to section 33 and 34 for a basic wiring diagram of the XMS4A-2A and the XMS4A-4A.
Please note: The diagrams serve only as a guide to assist with the installation.

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9. ASSESSING YOUR CAR’S FUEL SYSTEM
If your car is fuel injected already you can skip this section and move onto section 9. If it is
not fuel injected, then you really need to go through this section to see in what state your
car’s fuel delivery system is. We will provide information on how to get the fuel system ready
for your fuel-injected engine.
9.1 IS YOUR CAR READY FOR FUEL INJECTION?
The first thing you will need to check is the fuel pump and establish whether it is a high or
low-pressure pump. This can be tricky and potentially dangerous so we only recommend one
way: using a fuel pressure gauge. If you don’t have one please get one. With the fuel gauge
connected to the pressure side of the fuel pump and the pump running you should get the
following:
Low pressure pump = 0–0, 5 bar (0–7psi)
High pressure pump = 2–4 bar (29–58psi)
If you get the 2–4 bar reading you can skip the next section, if not then you really need to
read on about how to fix this problem.
NOTE: That if the engine is turbo charged the fuel pressure must be 2, 5 bar plus the
maximum boost required e.g.: 2, 5 bar plus 0.6 bar boost should equal 3.1 bar fuel
pressure under boosted conditions.
9.2 HOW TO MAKE YOUR CAR READY FOR FUEL INJECTION
Two fuel pumps are needed for the whole system to work. One from the fuel tank supplying a
surge tank, this is a low-pressure pump. This pump must be able to supply enough fuel to
keep the surge tank full at all times. A high pressure fuel pump to supply the fuel injectors.
Your engine must have fuel injectors - check Section 12.5 for more info. For details on the fuel
pump wiring see Section 18.2. More information on the setup of the auxiliaries can be found in
Section 23.
New fuel lines if needed can be made out of steel, copper or aluminum tubing. Rubber hoses
must be high pressure rated for pressures higher than 6 bar. Please ensure that you get
rubber hose that is also rated for fuel/gasoline. Always ensure that the fuel lines are securely
fastened to the chassis and engine.
Fuel pressure regulators vary in pressure and some are even adjustable. Ideally the fuel
pressure should be 2 to 2.7 bar at idle. Full throttle pressure on normally aspirated engines
should be 2.3 to 3.0 bar. On boosted engines the fuel pressure should be 2.5 bar plus the
boost.
Figure 1. Fuel System Layout
Fuel Tank Low pressure
fuel pump
Surge Tank
High pressure
fuel pump
High pressure
fuel line
Fuel rail
and injectors
Fuel pressure
regulator
Fuel return

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Unused fuel from the engine is returned through the regulator back to the surge tank, then
he surge tank should always be mounted higher than the high-pressure fuel pump. The
back to the fuel tank.
T
purpose of the surge tank is to ensure that the fuel line is not interrupted by air under high
speed cornering or under acceleration. The high-pressure pump must be fed by gravity. The
high-pressure pump must have a larger inlet supply than the return fuel line. See drawing
“enlarged view of surge tank” below.
Feed to high
pressure pump
Supply from low
pressure pump
Return to tank
Return from
fuel rail
200mm
10mm ID
8mm ID
8mm ID
8mm ID
Figure 2. Enlarged view of surge tank
afety: The fuel pump relay must be connected to the XMS4A
e
heck for leaks, if any fix them before moving on to anything else.
.3 CONCLUSION
ou have diagnosed your fuel system as to whether it is suitable for fuel injection. At this point
0. ASSESSING YOUR ENGINE
he engine will need to be assessed to determine if it has a compatible trigger wheel, cam
0.1 COMPATIBLE TRIGGER WHEEL
he XMS4A has a set of trigger patterns that it can work with, these are:
0 – 2 r higher)
S
The fuel pump must switch off when the engine stalls
Never connect the fuel pump to the key switch
Fuel lines must be securely fastened to the chassis
Rubber fuel lines must be rated for high fuel pressur
C
9
Y
you should have a fuel pressure of 2, 5 – 4 bar at the injectors. No fuel leaks and all fuel
piping nicely tucked away and securely fastened. The fuel pump is controlled by the XMS4A,
see section 18.2 for details on the wiring.
1
T
sensor (for sequential injection/ignition), typical sensors (used for compensation), injector
resistance and that it has the basics before we even try starting it.
1
T
6
36 – 2 (Firmware 25 o
36 – 1
24 + 1
24 + 2

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Which one does your engine have?
If your engine has a compatible trigger wheel and a pickup sensor fitted go onto section 9.2.
The best way to find out is to consult the engine manufacturer. You could also ask your local
garage if they know what trigger wheel your engine has on it. If you don’t know or are unable
to find out what trigger wheel (if any) is on the engine then you can fit a compatible wheel and
let the question rest. We recommend using a 60 –2 tooth wheel. This trigger wheel has 58
teeth and 2 missing teeth. It should be called 58 – 2 but the industry norm is 60 – 2. Ok now,
this trigger wheel must be connected to the crankshaft somehow. The normal place is on the
crankshaft pulley. See section 12.3 on how to install the compatible wheel.
10.2 CAMSHAFT SENSOR
This sensor reads off of a single tooth wheel on the camshaft. This signal repeats every 2
revolutions of the crankshaft. This signal is necessary for sequential ignition and injection. If
your engine does not have a cam sensor but you want sequential ignition and injection then
get an engine that has a cam sensor. Do not try to fit your own cam sensor.
10.3 HOW TO INSTALL A COMPATIBLE WHEEL AND PICKUP SENSOR
NOTE: If you are unable to weld or fabricate metal, rather get a machine shop to do
this part of the work for you.
First you need to get the engine onto TDC. Most engines have timing marks on the crank
pulley and on the surrounding covers. If your engine has marks then simply align the marks
so that the crank pulley mark and the 0 deg mark line up. If your engine has no timing marks
you will need to make some of your own. Follow these steps to make your own timing marks
on your engine:
•Locate number 1 spark plug (it is the one closest to the cam belt or cam chain)
•Take number 1 spark plug out
•Use a long screwdriver to touch the top of the piston through the spark plug hole
•Turn the engine very slowly by hand (you can use a spanner or ratchet)
•Observe that the screwdriver moves up and down as the engine is turned
•When the screwdriver is at it’s highest point, TDC is reached
•Use a white marker to make your own timing marks on the crank pulley and
surrounding covers. These marks should be in a place that is easy to see as you will be
using them again in section 26
Crank pulley
Engine on TDC
TDC
0
Engine rotation
Figure 3. Crank Pulley

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With the engine on TDC (top dead center) it is time to see where the pickup sensor will be
mounted. Choose a place that is easy to access and will not get in the way of any pulley belts.
The pickup sensor must be mounted so that it is perpendicular to the trigger wheel. Once a
suitable location has been decided upon the crank pulley must be removed.
Note: You can get a 60 – 2-tooth wheel, which has the two teeth missing, or you can get a
wheel, which has 60 teeth with no missing teeth. Care must be taken if you are fitting the 60
– 2 tooth wheel with the missing teeth as the gap in the teeth must be in a specific location in
relation to the pickup sensor and TDC. At TDC the gap must be 50 – 80 degrees passed the
sensor in the direction of engine rotation. See picture below.
Magnetic
Sensor
60 - 2 Tooth Wheel Setup
with the engine on TDC
Figure 4. 60 – 2 Tooth Wheel Setup
The 60 – 2 tooth wheel must be secured to the crank pulley as central as possible. We
recommend that once the trigger wheel is secured to the pulley; get a machine shop to skim
the trigger wheel’s teeth in a lathe. This will ensure that the 60–2-tooth wheel runs true and
that the XMS4A will get a nice, even signal. Fit the crank pulley back onto the crank. Make a
bracket for the pickup sensor and mount the sensor and bracket in place. The gap between
the sensor and the pickup wheel should be 0.8mm. If you have fitted a wheel with no missing
teeth you need to remove two teeth from the wheel. See Figure 4, above.
10.4 WHICH SENSORS ARE MISSING?
For the XMS4A to be an effective management system it requires certain sensors to give it
information on the changing engine conditions. The most common sensors are listed in section
17. Should you need the following sensors, we (Perfect Power) can supply them.
•Engine temperature
•Air temperature
•AMP
10.5 INJECTOR RESISTANCE
The XMS4A has 2 amp injector drivers, each injector driver is capable of driving 1 x 10 ohm
injector or 2 x 20 ohm injectors. What injectors do you have? To find out you must measure
each injector’s resistance with an ohm meter (Multi Meter). 2 ohm injectors will be a problem
and you will need external injector drivers. We can supply external injector amplifiers that are
rated at 7 amps and 25 amps.

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10.6 MAKE SURE THE ENGINE HAS THE BASICS
There must be enough oil in the crankcase, check the dipstick. There must be water in the
radiator. The alternator belt must be properly adjusted so it will not slip. The battery must be
fully charged.
10.7 CONCLUSION
You have a compatible trigger wheel on your engine. The injectors have been measured and
the XMS4A or an external amplifier will be driving them.
11. WHERE TO FIT YOUR XMS4A?
This is extremely important to read as you need to find a suitable location to mount your
XMS4A to avoid damage to the unit or vehicle. If you plan on installing your XMS4A where
there was an existing management system you should read this section too.
11.1 SUITABLE PLACES
The best place to mount the unit isn’t always the easiest. Usually best locations are as follows:
•Under the dashboard. There is normally enough space. It is free of moisture and
excessive heat.
Figure 5. Typical “under the dashboard” installation
•Center consol. It is also free of heat and moisture but may have space limitations.
•Driver sidekick panel. Free from heat and moisture. Some vehicles have space
limitations.
•Passenger side front kick panel. Same as driver side but most vehicles have enough
open space to mount the XMS4A there.
•Under driver or passenger seat. Very good location. Free from heat and moisture. Lots
of space.
•Rain tray. This can be a good location provided that your particular location in the rain
tray is waterproof. The XMS4A is not waterproof so it must be protected from moisture.
There are of course other locations and should you find one ask yourself three questions:
1. Is there enough space for my XMS4A to fit in there?
2. Is this going to be free from moisture at all times?

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3. Is the XMS4A going to remain well below 60 degrees Celsius?
If all 3 answers are YES, then fit your XMS4A there.
Mount your XMS4A firmly in place. The XMS4A should be mounted so that the casing is not
exposed to any stress. Note: The typical length of the XMS4A harness is 1, 5 meters long, so
consider this when choosing your location. Some people don’t mount the XMS4A but just tuck
it away. You can do this too but make sure that there is no stress on the wiring harness.
11.2 UNSUITABLE PLACES
•Anywhere in the engine bay. Why you say? The engine bay is a major heat generating
and heat-retaining cell. The XMS4A has been designed to be exposed to a maximum
temperature of 60 degrees Celsius. (140 degrees Fahrenheit). Under bonnet
temperatures exceed this limit and will cause the XMS4A to fail. If your existing engine
management system was mounted onto the engine DO NOT mount your XMS4A on top
of it.
•In the rain tray. This is potentially a bad location if it is not completely free from
moisture at ALL times. To test the location you can always fill a bucket or use a hose
pipe and spray water on the rain tray with the bonnet closed. Test circumstance should
be with the bonnet closed as the car would normally be driven. If any moisture enters
your chosen location, disregard it and refer to section 10.1 for another possible
location.
•Away from heat generating devices, for example on top of the exhaust tunnel or
directly in front of the heater vents.
•Anywhere the XMS4A can get wet. Pretty simple to understand but if you know that
your car leaks water by the passenger side then don’t mount your XMS4A anywhere
near there.
•In the Boot. This is a great place for spare tires and speakers. I don’t recommend it
because the possibility of your XMS4A getting accidentally damaged by some heavy
piece of equipment is too high.
•Anywhere the XMS4A could be exposed to excessive vibration.
•Under front passengers feet. Some vehicles have a protective metal case under the
passenger’s feet. This case protects the existing engine management system. If your
vehicle does not have a protective case, don’t mount your XMS4A there.
11.3 CONCLUSION
You now have mounted your XMS4A in a suitable place where it will not come into harms way.
Now we need to do the same with the ignition amplifier.
12. WHERE TO FIT THE IGNITION AMPLIFIER?
This section is extremely important, as you need to find a suitable location to mount the
ignition amplifier to avoid damage to the unit or vehicle. The XMS4A and the ignition amplifier
must be fitted at least 1 meter apart.
12.1 SUITABLE PLACES
The best place to mount the unit isn’t always the easiest. Usually the best locations are as
follows:

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•Under the dashboard. There is normally enough space. It is free of moisture and
excessive heat.
•Center consol. It is also free of heat and moisture but may have space limitations.
•Driver side kick panel. Free from heat and moisture. Some vehicles have space
limitations.
•Passenger side front kick panel. Same as driver side but most vehicles have enough
open space to mount the ignition amplifier.
•Under driver or passenger seat. Very good location. Free from heat and moisture. Lots
of space.
•Rain tray. This can be a good location provided that your particular location in the rain
tray is waterproof.
There are of course other locations and should you find one ask yourself four questions before
fitting the ignition amplifier:
1. Is there enough space for the ignition amplifier to fit in there?
2. Is this going to be free from moisture at all times?
3. Is the ignition amplifier going to remain well below 60 degrees Celsius?
4. Is the ignition amplifier more than 1 meter from the XMS4A?
If all 4 answers are YES, then fit the ignition amplifier there.
12.2 UNSUITABLE PLACES
•Anywhere in the engine bay. Why you say? The engine bay is a major heat generating
and heat-retaining cell. Ignition amplifiers generate heat as they operate, any extra
heat can cause the amplifier to fail.
•In the rain tray. This is potentially a bad location if it is not completely free from
moisture at ALL times.
•Away from heat generating devices. For example on top of the exhaust tunnel or
directly in front of the heater vents.
•Anywhere the ignition amplifier can get wet.
12.3 CONCLUSION
You now have mounted your ignition amplifier in a suitable place where it will not come into
any harms way.
13. SCREENED CABLE
This section is about a type of cable that provides resistance to potential noise. Why we use
these shielded wires and what gains we get out of it? If you are having no RPM or interference
problems you can move onto section 16.