Dynamic Digital Fuel Injection - Buell X1 2002 Service Manual

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DYNAMIC DIGITAL FUEL INJECTION (DDFI)
INTRODUCTION
The Buell Dynamic Digital Fuel Injection (DDFI) System pro-
vides microprocessor-based electronic engine management
for the 1203cc Buell Thunderstorm engine. The DDFI system
has the following features:
Independently mapped spark and fuel control.
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Engine and air temperature compensated fuel delivery.
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Engine load measurement through throttle position.
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Single point spark delivery (no waste spark).
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Sequential port indirect (manifold) fuel injection.
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Open/Closed-loop air/fuel control.
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Automatic enrichment at start.
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Engine speed and position determined using a single
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sensor (Cam Position Sensor).
Full diagnostic capability compatible with the SCANA-
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LYZER (Part No. HD-41325).
Returnless fuel system (excess pressure relieved in tank
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by Fuel Pressure Regulator Valve).
The DDFI system uses six sensors to monitor the operating
conditions of the engine and make decisions as to spark and
fuel delivery. These sensors are:
Throttle position (TP) sensor.
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Camshaft position (CMP) sensor.
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Engine temperature (ET) sensor.
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Intake air temperature (IAT) sensor.
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Oxygen (O2) sensor.
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Bank Angle Sensor (BAS)
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The DDFI system also analyzes how the engine performs
during a ride. It then stores this information internally so it will
be available for the next ride.
2002 Buell X1: Fuel System
GENERAL
The Buell DDFI operates both as an open and closed loop
system which allows it to adjust for all possible operating con-
ditions. High lift cams make it necessary for an open loop
system at idle and at wide open throttle. During open loop
operation, the system utilizes programmed fuel and spark
maps in the ECM which provide stable idle and ease of cold
starting, and maximum power at wide open throttle (WOT).
During closed loop operation, the system relies on input from
the O2 sensor to provide for the most efficient, stoichiometric
air fuel mixture (14.6:1) which results in reduced emissions,
good fuel economy and power. In order for the system to
enter closed loop operation, the following conditions must be
met:
O2 Sensor at operating temperature (Engine at normal
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operating temperature).
Operation above 2500 RPM with engine under load
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(approximately 40-60 mph in 4th or 5th gear).
By using both open and closed loop systems, engine perfor-
mance is continuously tuned to compensate for changing
conditions and provide maximum performance.
FOR MORE INFORMATION
To learn more about the Buell DDFI system, read the follow-
ing topics in this section. A system diagram can be found on
the next page in Figure 4-1.
Troubleshooting
4.3 DIAGNOSTIC INTRODUCTION.
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4.4 CHECKING FOR TROUBLE CODES
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4.6 CHECK ENGINE LAMP
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4.9 INITIAL DIAGNOSTIC
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TABLE 4-5. TROUBLE CODES AND FAULT CONDI-
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TIONS.
Fuel Injection Components
4.29 ELECTRONIC CONTROL
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4.30 CAM POSITION SENSOR AND ROTOR
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4.32 OXYGEN SENSOR.
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4.33 ENGINE TEMPERATURE
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4.34 BANK ANGLE SENSOR.
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4.35 INTAKE AIR TEMPERATURE
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4.36 THROTTLE POSITION SENSOR
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4.40 FUEL PUMP.
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4.41 THROTTLE BODY AND INTAKE
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4.2
.
DIAGNOSTICS.
CHECK.
MODULE.
SENSOR.
SENSOR.
MANIFOLD..
4-3