OBD-II Scanner
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Ford Kas (and all cars manufactured from 1996) come with an on-board
diagnostic port subscribing to the OBD-II standard - which reveals certain
information about the engine management and emissions control via the ECU. However, the diagnostic port also reveals 
other engine variables,
too. It is this port that the Ford
technician plugs his diagnostic computer in to read the fault codes. However, if you know how to decode the
signals, it’s entirely possible to write a computer application in order to
ascertain what is happening in the engine on a real-time, or near real-time,
basis.
The
trick is then simply displaying this information to the world at large.
Fortunately,
there is an entire cottage industry devoted to OBD-II diagnostic and live information
scanning. These scanners are useful for
home mechanics who need to diagnose a fault code from their ECU, or for information buffs and
nerds who want to know what their car’s coolant temperature is!
There
are a number of different hardware solutions, and it’s entirely possible to
hook your car up to a Windows laptop or PDA.
All OBD-II ports have to
provide certain information - engine speed and coolant temperature being the
two that I am most interested in - and certain manufacturers also provide enhanced
data, including Ford. These software
enhancements are generally quite expensive for what they offer - but you do get
a lot of information! In the case of
the Enhanced Ford data, up to one hundred and forty five variables!
Some
of the software solutions also provide the user with the ability to control
certain aspects of the engine management unit, including the cooling fan (being
able to switch it on and off, into either low or high speeds). This facility may be useful for an element
of pre-emptive cooling, especially in the summer.
After
a lot of deliberation, and following a change of PDA I eventually decided
to use the Harrison R &
D Solution and import it myself from Texas. There were three reasons for going with the Harrison solution -
one, the product specifications, two being the excellent customer service I’ve
received from them, and three being the price.
At
the time of writing, the OBD-II hardware and software has been installed in
Kermit for a number of months now. I
use either the Palm m130 or the Palm m515 with the OBD-II Scanner set up
– each has its own merit! The kit is
compatible with all PalmOS devices that use Palm’s Universal Connector.
In
conjunction with the OBD-II hardware, I also bought an Arkan PDA holder via
eBay.
Harrison R & D’s OBD-II Software
I’m
using version 7·1 of the Harrison R & D Software, which appears to be very
similar to version 6·0 except it the important addition of data logging. It’s through data logging that I’m able to
chart what the Endura-E is doing.
Use a Suitable PDA
All
PalmOS devices that I’ve reviewed on www.pda.dervman.com are up to the task of displaying real
time OBD-II variables. Admittedly,
those models with a faster screen (step forward the Palm m515) will be a bit easier to use than those with
a notably sluggish screen refresh (say hello to the Palm IIIc) but all are capable of displaying the
necessary variables.
The
choice between a colour and monochrome
device is largely up to the individual.
Many colour screens lose their advantage when in reasonably bright
lighting, such as outside in daylight, and many backlit screens can be
uncomfortably bright at night.
One
must also consider the likelihood of ever replacing their PDA for a newer
model, or if the PDA will be used for other purposes.
After
careful consideration of the above, my decision was swayed by the type of
connector that I’ll use for the PDA. To
this end, Palm’s Universal Connector has been in use for some time now across a
variety of models, including the very latest PalmOS devices and - crucially -
the Palm m130 and Palm m515. This means that if I were to replace either of these PDAs with a
PalmOS 5·x device (which is, admittedly, unlikely at the time of writing)
I will be able to use the same interface.
I was also reasonably confident that between the m130 and m515,
I would have the ideal compromise between battery life, screen usability and
device performance. As it happens, the
m515’s only weakness is that the screen backlight causes a near-perfect
reflection of the screen in the windscreen, but of course during the day one
does not require the backlight to see the screen. However, the Palm m130 has a screen that relies on the backlight
for visibility, but it does not cast a reflection on the windscreen - this in
conjunction with the relatively small size of the screen means that it is an
especially useful device for night time OBD-II Scanner duties.
Real Time Sensors
Kermit’s
OBD-II Scanner can read two of fifteen sensors in real time, or near real time.
Short Term Fuel Trim B1 and Long Term Fuel Trim B1
The Calculated Load data
provides a useful insight into how hard the Endura-E
is working at that juncture. Calculated
Load is simply how hard the engine is working relative to how hard it can work
under those individual circumstances, expressed as a percentage. In other words, if the Calculated Load
figure is showing 50%, the engine could provide twice as much torque as it is
doing.
Of course, because the
Calculated Load figure varies according to that precise moment, a figure of 70%
showing at you accelerate from 2,000 rpm is not the same as 70% accelerating
from 3,000 rpm, since the peak torque output of the engine will be different at
these two engine speeds.
This can best be demonstrated by
accelerating below 2,500 rpm in a lower gear, the engine speed at which the
Endura-E produces peak torque. If a
constant amount of pressure is maintained during the acceleration period, the
Calculated Load figure falls as the engine speed approaches 2,500 rpm.
With the engine simply idling
with no electrical circuits, the Calculated Load is typically around the 25%
level. Under modest acceleration at low
speeds, this typically increases to around the 50% level - in other words, the
engine is delivering half of the torque that it can do under those
circumstances. Increasing the pressure
on the accelerator naturally increases the torque output of the engine, which
in turn increases the acceleration. It’s
not unusual for the engine to be delivering peak torque without full throttle
being applied.
There is a discussion page on
the Calculated Load and how it is influenced by electrical circuits here.
When cruising at 60 mph on the
level, the Calculated Load figure is approximately 60%.
This chart shows the Engine Load
and Speed of Kermit during an overtake manoeuvre. We start the graph with us on the approach to a HGV. At the very start, just before the orange
shaded area, we’re maintaining 56 mpg.
Then, during the next stage, the HGV’s speed is changing quite a bit
with commensurate changes in Kermit’s speed and engine loading. As we move from the orange to the green bit,
I change down into fourth ready for the overtake.
Note that the engine is working
at 100% Calculated Load as we accelerate up to 70 mph. Then, as we reach 70, the load drops to the
overrun level (around 20%) – as I bring the speed back down to 60 mph.
Unfortunately, shortly after the
overtake, we enter a 30 mph speed limit – note how the engine load drops to the
overrun level as the speed drops. Then
when leaving the limit we use quite a bit of power to get back up to up 56 mph
again.
I’m sure I don’t have to discuss
what this sensor shows? Yup; you
guessed it, it shows the engine coolant temperature, in either degrees
Fahrenheit (°F) or Celsius (°C).
The Endura-E’s cooling system is discussed in greater detail here.
Short
Term Fuel Trim B1 and Long Term Fuel Trim B1
These two variables show the
fuel mixture as dictated by the ECU. When the trim is 0·000 the engine is running
at the optimum air:fuel ratio of 14·7 to 1.
When the figure is greater than 0 the ECU is enriching the mixture and
when the figure is below 0, the ECU is leaning the mixture. The ECU enriches the mixture when the engine is cold or when maximum
power is required, conversely the ECU leans the mixture out a little during
deceleration.
The Manifold Pressure sensor is
essentially broadly similar to that of a vacuum gauge, measured in kPaA.
When idling and with the foot brake
off, the meter typically reads 28 kPaA.
Use the footbrake and this rises slightly, but as soon as you
accelerate, the meter ascends - it’ll peak at around the 100 kPaA level. Ease off with the car in gear and the
manifold pressure drops to the 20 kPaA level.
This shows the engine speed in
revolutions per minute. The standard Endura-E produces peak torque at 2,500
rpm and maximum power at 5,000 rpm. After
using the Bluefin device, Kermit’s Endura-E produces peak torque at 2,300
rpm and maximum power at 5,600 rpm.
This shows what the vehicle
speed sensor is reporting to the ECU
in either kilometres per hour or miles per hour (the miles per hour figure
is a calculation based in kilometres per hour). The speedometer is optimistic to the vehicle speed sensor by
around ten percent. The vehicle speed
sensor is calibrated for running on brand new 155/70 tyres on a 13” rim and the
reported speed will differ from your true ground speed.
This variable shows the ignition
advance in degrees. The ECU adjusts the ignition advance
depending on a number of factors, primarily how much power the driver wants and
what the engine is otherwise doing. Ignition
advance is a complicated subject and at this juncture I don’t completely understand
the topic. Look for an article in due
course!
Following on from my KITS experimentation, I’ve used the OBD-II
Scanner facilities to monitor Kermit’s induction temperature. As it happens, the data and conclusion from
KITS has proven to be reasonably accurate - the intake temperature is, of
course, associated with the temperature under Kermit’s bonnet, which is turn is
associated with the cooling system’s radiator, the air conditioning system’s condenser, and of course how
quickly you’re driving (since the quicker you drive, the more air is forced
through the underbonnet area).
The intake air temperature is
discussed in greater detail here.
This shows where the accelerator
pedal is positioned with 16·9% at rest and 94·5% showing full throttle.
Oxygen
Sensors (Oxy B1, S1, Oxy B1, S1 Fuel Trim, Oxy B1, S2, Oxy B1, S2: Fuel Trim)
These four figures show the
voltage across Kermit’s two oxygen sensors.
The first sensor (B1 being for bank one, S1 being for sensor one)
is the pre-catalytic
converter sensor, which you can see protruding from the manifold head shield in the Endura-E page. The second sensor is for the post-catalytic converter sensor,
the one that you can only see if you get under the Ka.
At the time of writing I’m working
on an article discussing oxygen sensors and when it’s complete I’ll post it up
on the website somewhere.
This shows the distance covered
with the engine fault warning light illuminated. It seems to be there so that the mechanic can adjust your bill
when you bring the car in for a service – the further you’ve driven the higher
the bill! J