start stop button ASTON MARTIN DB7 1997 Workshop Manual

ffi:
The Aston Martin Lagonda Diagnostic System
Users Guide
Idle Fuelling Trim - 95 MY
This program is used to check and if necessary reset the
fuelling level at idle to ensure that the specified idle speed
and emission levels are attainable. The throttle
potentiometer adjustment sequence must be completed
before the fuel trim sequence can be run.
Note: The throttle setup must be completed before
attempting to set the Idle Fuelling Trim. An error in
throttle
stop,
throttle cable or throttle pot
adjustments can
cause serious
difficulties in setting the Idle Fuelling.
Select Idle Fuelling Trim from the Engine Setup

Menu.
(The PDU connections are
as
fortheThrottle
Potentiometer Adjustment.)

1.

3.
StarttheDB7engineand allow itto warm to normal
operating temperature.
Followthescreeninstructionstorunthe idle fuelling
trim procedure.
Observe the bargraphs for oxygen sensors A and B.
The bargraph indications should oscillate evenly
about the 0% position on the bargraph.
BANK

-100%

BANK

-100%

Idle
Fuel
Trim
Closed Loop Control Data
Q Idle
trim:
8%
9^B 1 1
Oxygen Sensor Fuel Trim 100%
B Idle
trim:
5% —1 1 1

«^
1 1 Oxygen Sensor Fuel
Trim
100%
Idle Fuelling Trim Display
5. Ifthebargraphindicationsarenotoscillatingevenly
about the 0% position, select the A (cylinders 1, 2
and 3) or the B (cylinders 4, 5 and 5) sensor. The
Increase/Decrease buttons will appear.
6. Adjust the fuel trim as required to achieve even
oscillation about the 0% mark for both sensors.
When the adjustment is correct, select the 4 icon
and confirm that the idle fuelling trim is correct. On
confirmation of the adjustment, the PDU will exit
from the idle fuelling program.
7. On completion of the procedure, select Exit from
the Engine Diagnostics Software.
September 1996 9-39

^
The Aston Martin Lagonda Diagnostic System
Users Guide
Parameter Name
Parameters can be fault codes, inputs to, or specific
outputs from, a vehicle control module.
The number of parameters selectable is limited to 32.
If the number of parameters available for customization
exceeds the d isplay
area,
the arrow buttons wi
11
be present,
allowing display area scrolling.
The parameters declared to Datalogger are initially
presented in alphabetical order.
Record Enabled
Record enabled is used to select which signals are to be

recorded.

To select a signal for recording, touch the rectangle next
to the signal name.
The record button will then be displayed.

Nofe:
Additional rectangles may appear in other columns
beside a selected signal name, indicating that the signal
units may be changed or that the signal may be used
as
a

trigger.

It should be noted that the more parameters you select to
record the slower the PDU's sample rate will be for each
parameter e.g. The PDU may be able to monitor six
parameters sampling each parameter twice a second. If
the number of parameters is increased to twelve then the
PDU would only be able to sample each parameter once
per second, thus reducing its ability to capture fast faults;
therefore it
is
recommended that the number of parameters
is kept to a minimum.
Display Order
Parameters may be displayed on the waveform/ bargraph
screen in any order.
To set the parameter display order, press the required
rectangle to create a numbered list.
Note: It
is
not
necessary to
display all of the parameters
required to be recorded.
This has particular benefits if a parameter is to be used as
a trigger but is not required to be displayed.
Trigger Action
For a detailed description of trigger action, refer to the
Trigger Customisation description on the following page.

S.I.
Units
Certain parameters can be measured / displayed in a
number of different units eg temperature in °C or °F. If a
rectangle appears around the displayed units in the
'S.I.'

column then the units are selectable. Each time the
rectangle is pressed, the selectable units scroll one step
through the available options.
Other Features
To make parameter customization easier two icons have
been introduced on to the bottom of the screen, these are:
This icon simply puts all ofthesignals selected for
recording in alphabetical order irrespective of
the language.
A B C
This icon will put all of the signals selected for
recording at the top of the parameter list in
numerical order.

^T/^

After the parameter customization process is completed,
return to the Datalogger main menu.
Default Customisation
To cancel all customisations, press the
Customisation Reset
icon.
This will reset the
customisation on all parameters to the default

setting.

Trigger Customisation
Datalogger operates using a 'rolling memory'.
When the Record icon is selected on the waveform
display, PDU will start to record data, it will then continue
to record data until its memory is
full.

At this point it will continue recording by overriding the
oldest
data.
This process will continue indefinitely or until
the trigger is activated.
When the trigger is activated it performs a number of
functions.
a) The first function istoplaceazerotimepointwithin
the stored data, this enables the trigger point to be
easily accessible in later stages.
b) The second function is to set a timer, ensuring that
the PDU wil
I
only continue recording for the time
selected in 'test-duration'.
September 1996 9-57