Installation Instructions for WEGO IIID
Wide-Band Exhaust Gas Oxygen
Sensor Interface (Automotive Version)
Daytona Sensors LLC
Engine Controls and Instrumentation Systems
CAUTION: CAREFULLY READ INSTRUCTIONS BEFORE PROCEEDING
3. 18 x 1.5 mm weld nuts must be welded onto the
OVERVIEW
exhaust pipe. After welding, run an 18 x 1.5 mm
tap through the threads. Failure to clean the
threads may result in sensor damage. Note that
most automotive muffler shops are familiar with
oxygen sensor weld nut installation on custom
pipes. Do not install the sensors until after the free
air calibration procedure described in the following
section. Always use an anti-seize lubricant such as
Permatex 133A on the sensor threads.
The WEGO IIID is a dual channel air/fuel ratio
(AFR) metering system designed to be used with an
existing data acquisition system. The system has two
0-5 volt analog AFR outputs. The compact size and
wide supply voltage range also allow operation from
small rechargeable batteries in a broad range of
applications.
The system uses low cost Bosch LSU 4.2 5-wire
wide-band oxygen sensors. By utilizing miniature
surface mount electronics technology, digital signal
processing techniques, and a switching power supply
for the sensor heater, the WEGO IIID provides the
same level of accuracy as lab systems costing
thousands of dollars.
Figure 1 – WEGO IIID
REPLACEMENT SENSORS AND
ACCESSORIES
The WEGO IIID uses standard Bosch LSU 4.2
sensors used on a VW production application (Bosch
P/N 0 258 007 057/058 or VW P/N 021 906 262B). The
proprietary VW connector is replaced with a smaller
Deutsch DT-04-6P. We offer replacement sensors with
the Deutsch connector installed.
If you are testing multiple engines, we also offer
additional 18 x 1.5 mm weld nuts for sensor mounting
and 18 x 1.5mm hex socket plugs that screw into the
weld nuts and allow removing sensors after tuning.
INSTALLATION
1. For multiple unit installations (individual cylinder
AFR monitoring), please refer to the WEGO IIID
Race Pack Tech Note. Turn off the ignition switch
and disconnect the battery ground cable before
proceeding.
4. Install the WEGO IIID unit. The unit is fully sealed,
but should be mounted away from sources of
engine or exhaust heat. The unit can be secured
by means of two #8 screws through the mounting
flanges. Use nylon tie wraps to secure the wire
harness near the unit.
2. The Bosch LSU 4.2 sensors should be located on
the header pipe about 6-8 inches from the head
flange. Ideally the sensor tip should face down to
avoid accumulation of condensation. When
5. Connect the Bosch sensors to the 6 pin mating
connectors on the WEGO III wire harness.
Extension cables (P/N WEGO-CBL-12) are
available. The cable for sensor 1 exits at the top of
the WEGO III housing and is identified with a
yellow band.
choosing a mounting location, allow several inches
clearance for the sensor wire harness. The wire
harness must exit straight out from the sensor. Do
not loop the harness back onto the sensor body.
Daytona Sensors LLC, 933 Beville Road, Suite 101-I, S. Daytona, FL 32119
Page 1
WEGO IIID Automotive Version
9/2014
sensor or very high hydrocarbon levels in your
environment.
Operating Mode
Recommended AFR
11.5-12.5 AFR
Cold Start (first 30 sec)
The WEGO IIID includes internal diagnostics for
abnormal battery voltage (less than 11 volts or greater
than 16.5 volts), sensor open circuit, and sensor short
circuit conditions. A fault condition causes the status
LEDs to blink at the slow rate.
0.78-0.85 Lambda
12.8-13.5 AFR
Idle
0.87-0.92 Lambda
13.0-14.0 AFR
EXHAUST CONSIDERATIONS
The WEGO IIID system may give inaccurate
results in certain situations:
Part Throttle Cruise
0.88-0.95 Lambda
12.5-12.8 AFR
Excessive exhaust back pressure. Wide-band
sensors are affected by back pressure. Excessive back
pressure causes exaggerated AFR indications under
rich and lean conditions, but has little effect at 14.7
AFR (stoichiometric). Race vehicle exhaust systems
are free flowing and problems with exhaust back
pressure are not likely.
Wide Open Throttle
(normally aspirated)
0.85-0.87 Lambda
Values down to 11.5 AFR
or 0.78 Lambda may be
used to reduce
detonation)
Exhaust reversion. Reversion is the term for a
negative pressure wave that can suck ambient air back
into the exhaust and cause an erroneous lean AFR
indication. Open “drag pipes” usually suffer from
reversion effects and may not be suitable for use with
the WEGO IIID except at or near wide open throttle.
Reversion effects will be most noticeable at idle, part
throttle low RPM, and decel.
Wide Open Throttle
(turbo/supercharged)
10.8-11.8 AFR
0.73-0.80 Lambda
DATA ACQUISTION
The 0-5 volt analog outputs (white and blue
wires) from the WEGO IIID are compatible with most
data acquisition systems that have available analog
inputs. We do not offer any technical assistance on
interfacing to your data acquisition system. You
must contact the vendor for support.
Excessive scavenging. Tuned exhausts in
combination with a high overlap camshaft profile can
pull unburned air and fuel mixture through the cylinder
into the exhaust and cause an erroneous rich AFR
indication. The same effect can occur with high boost
turbo/supercharger applications.
WEGO units are useful in a wide range of
engine tuning and testing applications. After free air
calibration, accuracy is 0.1 AFR or ±0.007 Lambda.
Misfiring. If the AFR is so rich that the engine
misfires, high levels of oxygen will remain in the
exhaust gas and result in an erroneous lean indication.
All WEGO units have the same scaling for the
0-5 volt analog outputs on the white and blue wires:
GASOLINE ENGINE TUNING
GUIDELINES
Gasoline:
Higher AFR values correspond to a leaner (less
fuel) condition. The practical operating range for most
engines using gasoline fuel is from approximately 11.5
to 14.7 AFR. Combustion of a stoichiometric mixture
(exactly enough air to burn all the fuel) results in 14.7
AFR indication. Automotive engines with catalytic
converters operate near 14.7 AFR during cruise and
idle. Race engines usually require a richer mixture to
limit cylinder head temperature and prevent detonation.
The table below lists reasonable AFR values for race
engines without emission controls.
AFR = 2 x (Vout + 5) or
Vout = (0.5 x AFR) - 5
Lambda:
Lambda = .1361 x (Vout + 5) or
Vout = (7.345 x Lambda) - 5
Additional scale factors are listed on our Tech
Daytona Sensors LLC, 933 Beville Road, Suite 101-I, S. Daytona, FL 32119
Page 3
WEGO IIID Automotive Version
9/2014
Note that when power is first turned on and the
sensors are not yet at their normal operating
temperature, the analog outputs are held at less than
0.20 volts. During free air calibration and while the
WEGO IIID status LEDs are rapidly blinking, the
analog outputs will be near 5.0 volts.
Figure 3 – Typical Dyno Hookup for WEGO IIID
INPUT
INPUT
DATA
ACQUISITION
SYSTEM
electrostatic discharge (ESD) across the WEGO
sensor damaging the sensor and WEGO unit.
DYNO WIRING HOOKUP
Refer to Figure 3. The power supply must be
located in close proximity to the WEGO unit. We
recommend mounting the WEGO unit on a panel next
to the dyno data acquisition system and then running
extension cables out to the sensors in the dyno room.
Keep all power and ground connections as short
as possible. Follow the exact layout shown in
Figure 3. Do not add additional terminal blocks or
connectors to power or ground connections.
WEGO POWER REQUIREMENTS
WEGO systems are intended for nominal 12 volt
automotive applications. Nominal 12 volt automotive
electrical systems on alternator equipped vehicles
typically operate at 13.8-14.4 volts while the engine is
running. The WEGO can operate from 9.0 to 18.0
volts.
WEGO units also feature low power
consumption (about 2 amps). For small engine
applications, you can power the WEGO for over one
hour from a 12 volt gel cell type rechargeable battery,
such as the type used for backup power in alarm
systems.
DYNO GROUNDING
Improper grounding will cause serious problems.
The dyno frame or chassis must be connected to
building electrical ground in accordance with National
Electrical Code (NEC) requirements.
Vehicles with nominal 12 volt total loss
electrical systems (no alternator) can momentarily drop
below the 9.0 volt minimum level when heavy loads,
such as fans or nitrous solenoids engage. This will
cause the WEGO to reset and result in a loss of data
for 10-15 seconds.
Vehicles operated on a chassis dyno will
generate considerable electrostatic charge. The
vehicle must be grounded to the dyno frame while in
operation. You can use a length of 16 AWG wire with
one end secured to the dyno frame and the other end
equipped with a heavy duty alligator clip that is
attached to the vehicle frame or other vehicle ground
point. Failure to ground the vehicle will lead to
Vehicles with nominal 16 volt electrical systems
equipped with race type alternators may reach 18.6
volts while the engine is running. The WEGO will shut
Daytona Sensors LLC, 933 Beville Road, Suite 101-I, S. Daytona, FL 32119
Page 4
WEGO IIID Automotive Version
9/2014
off if the voltage exceeds 18.0 volts. Call our tech
support before attempting to install any WEGO system
on a nominal 16 volt electrical system with an
alternator.
TROUBLESHOOTING FLOWCHART
Follow the troubleshooting flowchart shown
below. Experience has shown that most units returned
for warranty are OK and another problem, such as user
error, degraded sensors, or bad power connections is
later identified.
Troubleshooting Flowchart
NOTE: ALL TESTS PERFORMED
WITH SENSORS IN FREE AIR
STARTING
POINT
DO STATUS LEDS SLOWLY BLINK WHEN
POWER IS FIRST TURNED ON?
NO
YES
VERIFY +12V POWER ON RED WIRE.
VERIFY BLACK WIRES CONNECTED TO
GROUND. IS PROBLEM FIXED?
DO STATUS LEDS CONTINUE SLOWLY
BLINKING 60 SECONDS AFTER POWER
UP?
NO
YES
YES
NO
PERFORM FREE AIR CALIBRATION.
IS CALIBRATION SUCCESSFUL?
REPLACE WEGO
DONE
NO
YES
REPLACE SENSOR(S).
IS PROBLEM FIXED?
MEASURE VOLTAGE LEVEL ON RED
WIRE WITH DVM. IS IT GREATER THAN
11 VOLTS?
NO
YES
YES
NO
DONE
REPLACE WEGO
REPLACE SENSOR(S).
IS PROBLEM FIXED?
WEGO REQUIRES MINIMUM 11
VOLTS. FIX UNDERLYING PROBLEM
WITH VEHICLE ELECTRIC SYSTEM.
NO YES
DONE
REPLACE WEGO
IS PROBLEM FIXED?
NO
YES
DONE
CALL TECH SUPPORT
Daytona Sensors LLC, 933 Beville Road, Suite 101-I, S. Daytona, FL 32119
Page 5
WEGO IIID Automotive Version
9/2014
|