Transcript Document

Making Driveability
Profitable !
Instructor: John Forro
Copyright 2001 AST
Why do we lose money ?
•
•
•
•
•
•
•
What is our ROI?
What type of tech?
How do we charge?
How long does it take?
What is our true profit?
What about the risks involved?
Can everyone do it?
Copyright 2001 AST
What is our return on investment ?
• ROI is greater then any
other type of work
performed!
• Training, equipment and
information systems are
very costly investments,
are we getting the most
out of them?
• How long should it take to
pay back our investment?
Copyright 2001 AST
What type of technician is needed
for driveability work ?
• The technician needs to be
very highly skilled, stubborn
and extremely dedicated. A
true class “A” tech.
• How much will this lad cost
us?
• Does your shops driveability
tech truly make more money
for the shop then your gravy
guy?
Copyright 2001 AST
How does your shop charge for
this type of work?
• How does your shop
charge?
• Most shops charge 1hour’s diagnostic time.
• How long is spent on
diagnosing?
• Could your money tree
use some water?
Copyright 2001 AST
How long should MOST driveability
diagnostic work take?
• How long does a typical front brake
job take when replacing pads and
rotors with slip on rotors?
• What is you charge for this
procedure?
• Did you double your labor time
spent?
• Do you double your labor time spent
on diagnostic work?
Copyright 2001 AST
What is our true profit?
• Are we selling parts?
• Are we selling maintenance?
• Are we at least doubling our
labor time?
• What jobs did we miss out on
while doing this job?
• Are we on a recipe for
failure?
Copyright 2001 AST
What about risks involved?
• Do we always diagnose the
car in the time allotted?
• Do we always fix the job
right the first time?
• Does the customer always
allow us to repair the
vehicle.
• What about the elements?
Copyright 2001 AST
What are the answers to these
dilemmas?
• Don’t do driveability
work.
• Sell more maintenance
while doing our diagnostic
work.
• Diagnose in a half hour
or less!!!!!
Copyright 2001 AST
Can everyone do this?
• Practice these new
skills that we will
cover.
• Think outside of the
box!
• Work as a team!!!!
Copyright 2001 AST
The approach
•
•
•
•
•
•
•
•
•
Customer /PCM interrogation
Road test
Review codes/data stream
Review movie/freeze frame
Visual inspection
Learn what you don’t know
Quick-check tests
Circuit/component diagnostics
Road test vehicle performing
any necessary drive cycles.
Copyright 2001 AST
Typical lab scope screen
Volt Division
Grid
x
Time Division
Grid
Copyright 2001 AST
Trigger
Level
Definitions
•Coupling
•Amplitude
•Shape
•Duty Cycle
•Pattern
•Frequency
•Glitch
•Noise
•Slope
•Trigger Level
Copyright 2001 AST
Coupling
Coupling describes the type of signal being
sampled: an A/C signal or a D/C signal.
AC
Signal
Copyright 2001 AST
DC Signal
Amplitude
Amplitude refers to the overall height of
the signal.
Every component must reach a specific
height before the PCM can recognize the
Amplitude
signal!
HEIGHT
Copyright 2001 AST
Shape
This term is used to describe the overall
signature of an electronic signal, with its
Shape
unique curves or look.
Characteristic
Copyright 2001 AST
Duty cycle
This is a term used to define the on or off time
of a given signal.
Duty
Cycle
Copyright 2001 AST
Pattern or synchronization
Pattern or Synchronization pulses indicate
component location or trigger a sequence of
events to make them occur in the correct
order.
Sequence
Order in which the
signal is displayed
Copyright 2001 AST
Frequency
This is a term which simply means the amount
of times a signal repeats itself in a 1 second
time frame.
Frequency
Amount of times the signal is
repeated in a given time frame
Copyright 2001 AST
Glitch
This term is used to describe an intermittent
malfunction in either the circuit or
component being tested.
Glitch
Copyright 2001 AST
Noise
This term is used to refer to unwanted electrical
interference in a sensor’s voltage signal. This is
usually caused by high current devices such as
ignition components or alternators that generate
strong magnetic disturbance that is transferred to
the signal wire.
Copyright 2001 AST
Slope
Slope determines whether or not the scope
will trigger on a voltage that is going from
negative to positive or from positive to
negative. Use this scope adjustment when
you place the trigger point, depending on
how you want the trigger to respond to
voltage changes in the circuit being tested.
Copyright 2001 AST
Trigger level
Trigger level sets the voltage threshold
that the scope must see to start
displaying the waveform.
Trigger level is represented by a small x
on the left hand side of the screen.
Copyright 2001 AST
Preliminary mechanical tests
•
•
•
•
•
•
Check the levels
Visual inspection
Vacuum reading
Compression test
Cylinder leakage test
Do you do these tests on
most cars? Why not?
Copyright 2001 AST
Copyright 2001 AST
Copyright 2001 AST
Copyright 2001 AST
Drivers seat diagnostics
•
•
•
•
•
•
The interface decision
PCM strategies
Trouble code retrieval
Diagnostic help
Main inputs
Parameter diagnostics
Copyright 2001 AST
The scan tool
•
•
•
•
•
•
Temperature
RPM
Load
Demand
O2
Fuel trim / integratorblock learn
Copyright 2001 AST
Trouble code diagnostics
• The next time you get a
trouble code try
comparing the faulty
component to a
similar/related component
such as the one displayed
here.
• This could eliminate time
consuming flow charts
and false code
diagnostics!
Copyright 2001 AST
New age information
Copyright 2001 AST
Scope tips and tricks
• Learn all the functions
• Choose best possible
locations for hook ups
• Use PCM strategies
• Take up full screen !
• Check sensor/actuator and
PCM operation
dynamically.
Copyright 2001 AST
We need to know if there is a drain
on the battery, but if we
disconnect the cable and use
our amp meter, we may turn on
some unwanted lights. What
can we do?
This calculates to over a
half an amp drain, using
the 10mv = 1 amp scale.
Attach your low amp probe around
the negative battery cable.
Remember to zero your probe!
Copyright 2001 AST
The ignition system
• All problems can be
found by interpret ting
these patterns.
• Use fast scope.
• Test under load
Copyright 2001 AST
Normal primary ignition pattern
Coil
Primary
Off
100 volts per division
&
2 milliseconds per division
Transistor
Turn
On
Dwell
Current
Limiting
Resistor
Dwell
Copyright 2001 AST
Oscillations
Explanation of operation
Copyright 2001 AST
Primary signal areas of concern
Coil
Primary
Off
100 volts per division
&
2 milliseconds per division
Transistor
Turn
On
Dwell
Current
Limiting
Resistor
Dwell
Copyright 2001 AST
Oscillations
Typical bad module
Copyright 2001 AST
Secondary pattern relationship
Represents the voltage
requirement over the time or
duration of the spark.
Represents the
amount of voltage
needed to jump
the gap.
Copyright 2001 AST
Secondary ignition pattern
preliminaries
If it took as much energy to
jump the gap as it took to
maintain the gap, the pattern
would appear to be equally
proportioned. Remember, we
bend the rope in a L shape
Imagine if we
straightened out the firing
and spark line like a piece
of rope. Lets say that the
total voltage of that rope
was 20 K volts.
Now imagine for a moment that it took more energy to jump
the gap then normal. This is typical of a very lean condition.
We will no longer have as much available voltage to keep the
plug firing. Think of it as if we pulled one side of the rope,
the other will get shorter! This would most likely cause a
misfire.
Finally the opposite holds true if we require
very little voltage to jump the gap, we will then
have a great deal of voltage left to maintain the
spark. This is typical of a very rich or no
compression condition.
Copyright 2001 AST
Normal secondary pattern
Copyright 2001 AST
Spark line sloping up
Copyright 2001 AST
Spark line sloping down
Copyright 2001 AST
Turbulence
Copyright 2001 AST
Spark line has dippity-doo
Copyright 2001 AST
What could be wrong?
Copyright 2001 AST
Primary current/voltage signals
Copyright 2001 AST
Copyright 2001 AST
Current ramping diagnostics
Copyright 2001 AST
Secondary ramp diagnostics
Copyright 2001 AST
Real world ramp diagnostics
Copyright 2001 AST
Copyright 2001 AST
Secondary cheat sheet all
cylinders Normal Firing KV/
High Firing KV
Short Burn Times
 Lean Condition
 Wide Rotor To Cap Gap
 Coil Wire or Connections
 Rotor Wrong or Misaligned
 Coil or Saturation Problem
* Spark output with a spark tester installed should be at
least 20,000 volts (20 KV) with a burn time duration of at
least 7ms!
Copyright 2001 AST
Secondary cheat sheet single
cylinder
High Firing Voltage Peaks/Short
Burn Time
Low Firing Voltage Spikes/Long
Burn Time
 Open Wire
 Fouled Plug
 Wide Plug Gap
 Carbon Tracked Cap
 Corroded Secondary
Connections
 Damaged Secondary Plug Wire
Insulation Allowing Spark to
Short to Ground
Pull wire to see if internal or external problem!
Copyright 2001 AST
The fuel system
•
•
•
•
•
•
Check pressure
Check volume
Check amperage
Current ramp
Check fuel quality
Check pump speed
Copyright 2001 AST
Fuel tests
• Use today’s testing
procedures.
• If you must do “cave”
testing, make sure you
at least have ½ pint in
30 seconds.
Copyright 2001 AST
New tests
Copyright 2001 AST
What is new ?
•
•
•
•
Tests pressure
Tests volume
Tests dead head
Tests injectors
Statically/dynamically
• Tests injector flow rates
• Tests fuel pump amperage
and speed
Copyright 2001 AST
Mastering Techniques
• Remember, we don’t
learn how to use any
of these tests fixing
broke cars!
• You must learn on
good cars!!!!!!
Copyright 2001 AST
•
•
•
•
•
•
•
•
What we do…..
Nation wide training
National account training
Curriculim development
Automotive video training tapes
Write and publish automotive repair manuals
Local lemon law vehicle inspector
Equipment distributor for the following companies:
1. Hickok/Waekon
2. Interro
3. MPC wiring diagram cd’s
Repair problem vehicles for local shops
Copyright 2001 AST
Thank You !
I hope to see you all again real soon!
Copyright 2001 AST