Advanced Automotive Fault Diagnosis

22
Advanced automotive fault diagnosis
PORSCHE
Technical Data
Vehicle Identification
Model
944S
944
R-Cat
R-Cat
1989-93
1989-93
M44/52
M44/41
4/OHC
4/OHC
2479
2990
95
95
Map-h
Map-h
Crankshaft
Crankshaft
Bosch
Bosch
Motronic
Motronic
MFI-i
MFI-i
Flow
Flow
Yes
Yes
Yes
Yes
12.0
12.0
0.4-0.6
0.4-0.6
5000-7200
5000-7200
1-3-4-2
1-3-4-2
(0 261 200 088) (0 261 200 195)
5±3/840
10±3/840
184 (250) 6000 155 (211) 5800
Turbo
944 S2
928 GT
928 S4
R-Cat
R-Cat
1989-92
1989-94
M28/41/42
8/OHC
4957
235 (320) 6000
95
Map-i
Crankshaft
Bosch
LH-Jetronic
MFI-i
Mass
No
Yes
12.0
0.4-0.6
5000-7200
1-3-7-2-6-5-4-8
(0 227 400 034)
10±2/675
M28/47
8/OHC
4957
95
Map-i
Crankshaft
Bosch
LH-Jetronic
MFI-i
Mass
No
Yes
11.0
0.4-0.6
5000-7000
1-3-7-2-6-5-4-8
(0 227 400 164)
10±2/775
243 (330) 6200
1986-89
M44/04
4/OHC
2479
140 (190) 6000
95
Map-h
Crankshaft
Bosch
Motronic
MFI-i
Flow
Yes
Yes
12.0
0.4-0.6
5000-7200
1-3-4-2
(0 261 200 080)
10±3/840
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
o
ECU controlled ECU controlled ECU controlled ECU controlled ECU controlled
840±40
840±40
840±40
775±25
675±25
13-16/0.5-2.0
1.0±0.5
90
90
90
90
90
100
2500-2800
0.3
0.97-1.03
Bosch
0.7
Hydraulic
Hydraulic
3.5/6000
5/4000
5/5000
15W/40 (SF)
15W/40 (SF)
7.5
7.5
4.5
4.5
Dexron II D
7.3
90W
30 (AT)
∆ = setting not adjustable
75W/90
75W/90
15W/40 (SF)
7.0
7.0
75W/90
WR5DC
0.4-0.8
0.4-0.8
0.4-1.2
0.4-1.2
100
2500-2800
0.3
0.97-10.3
Bosch
WR7DC
0.6-0.8
Hydraulic
Hydraulic
100
2500-2800
0.3
0.97-1.03
Bosch
WR7DC
0.7
Hydraulic
Hydraulic
14.5-16/0.1-0.5
14.5-16/0.1-0.5
14.5-16/0.1-0.5
14.5-16/0.1-05
100
2500-2800
0.3
0.97-1.03
0.5 Max
0.5 Max
0.5 Max
0.5 Max
300
Bosch
Bosch
0.7
0.7
Hydraulic
Hydraulic
Hydraulic
3.5/6000
3.5/6000
6.5
7.0
75W/90
75W/90
2.0
2.0
6.0
90W
1.0 (AT)
Dexron II D
15W/40 (SF)
15W/40 (SF)
Hydraulic
WR5DC
WR7DC
Engine specially tuned for
Year
Engine
Capacity
Output
RON
Minimum octane rating
Ignition system
Description
Fuel system
Trigger location
Make
Type
Description
Type
Air metering
Combined ignition and fuel ECU
Diagnostic socket
Ignition coil supply voltage
Primary resistance
V
Ω
Ω
Secondary resistance
Firing order
no.
°Engine/rpm
°Engine/rpm
°Engine/rpm
°Engine/rpm
°Engine
°Engine/rpm
o without + with vacuum
Ignition distributor (ECU)
Ignition timing BTBC
alternative
a = without vacuum and basic timing
c = with vacuum and basic timing
b = without vacuum with basic timing
Ignition advance checks
Vacuum advance range
Idle speed
rpm
rpm
ppm
rpm
λ
Vol.%
Vol.%
Vol.%
Vol.%
°C
alternative
Oil temperature for CO test
CO content at idle - tail pipe
- sample pipe
HC content at idle speed
Increased idle speed for CO test
CO content at increased idle speed
Lambda at increased idle speed
Spark plugs
Valve clearance - inlet
Engine oil grade
Engine with filter
Gearbox oil grade
4/5 speed
refill
front/rear
Differential oil grade
Automatic transmission fluid
SAE (API)
litres
SAE
SAE
litres
litres
litres
= refer to Technical Information at end of this manufacturer
Type
Make
Type
Electrode gap
mm
mm
mm
bar
Compression pressure
- exhaust
bar / rpm
Oil pressure
(also see Spark Plugs list)
CO
2
/O
2
content at idle speed
Tuning and emissions
Service checks and adjustments
Lubricants and capacities
POR 3
kW (DIN hp) rpm
cm
3
No. of cylinders/Type
Code
1
2
1
2
3
4
5
Ref. No.
1064
2811
2810
2812
1073
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
3
4
5
o
2
1
Figure 2.13 Example data book example (Source: Autodata)

Diagnostic techniques
23
●
Repair times
●
Service schedules
2.9.2 Autodata
One of the best known and respected companies
for supplying automotive data is Autodata, both
in the UK and the USA.
This range of books and CDs (on subscrip-
tion) is well known and well respected. Very com-
prehensive manuals are available ranging from
the standard ‘Data book’ to full vehicle circuit
diagrams and engine management diagnostic tests
data (Figure 2.13).
Information about testing procedures is avail-
able as shown in Figure 2.14. These sheets include
Figure 2.14 Fuel injection testing example (Source: Autodata)

24
Advanced automotive fault diagnosis
test data as well as test procedures related to spe-
cific vehicles or systems.
Bosch ESI[tronic]
There are already over 10 million cars in the UK
and over 60 million in the USA! Most of these
now have engine management systems.
These engines need sophisticated test equip-
ment to diagnose faults and system failures.
Ineffective diagnostic work inevitably leads to
vehicle problems, dissatisfied customers and
labour costs which far exceed a realistic invoice
value for the workshop.
Clearly this is where good data comes in. The
Bosch system runs from a DVD and as well as
information about test procedures and test results,
much more is included as well (Figure 2.15).
Summary
Both of the previously mentioned sources of data
are excellent – and essential. It is possible to
carry out diagnostic work without data, but much
more difficult and less reliable. The money will
be well spent.
Figure 2.15 ESI[tronic] data (Source: Bosch Press)
Knowledge check questions
To use these questions, you should first try to answer them without help but if necessary, refer back to
the content of the chapter. Use notes, lists and sketches as appropriate to answer them. It is not neces-
sary to write pages and pages of text!
1. List the six-stage diagnostic process in your own words.
2. Explain how the six-stage process is used by giving a simple example.
3. State the length of a standard piece of string and explain why this is relevant to diagnostics!
4. Describe how to carry out tests for an electrical short circuit.
5. Explain using a sketch, what is meant by ‘black box’ faultfinding.

3.1 Basic equipment
3.1.1 Introduction
As the complexity of the modern vehicle con-
tinues to increase, developments in suitable test
equipment must follow. Many mechanical and
electronic systems now have ECUs, that contain
self-diagnosis circuits. This is represented by
Figure 3.1. On earlier systems this was done 
by activating the blink code output to access the
information held in the ECU memory. This was
done in some cases by connecting two wires and
then switching on the ignition. It is now usual to
read out the fault codes on a scanner.
Diagnostic techniques are very much linked to
the use of test equipment. In other words you
must be able to interpret the results of tests. In
most cases this involves comparing the result of
a test to the reading given in a data book or other
source of information. By way of an introduction,
the following table lists some of the basic words
and descriptions relating to tools and equipment.
Hand tools
Spanners and hammers and screwdrivers 
and all the other basic bits!
Special tools
A collective term for items not held as part 
of a normal tool kit. Or items required for 
just one specific job
Test equipment
In general, this means measuring equipment.
Most tests involve measuring something and 
comparing the result of that measurement 
to data. The devices can range from a simple 
ruler to an engine analyser
Dedicated test 
Some equipment will only test one specific 
equipment
type of system. The large manufacturers 
supply equipment dedicated to their 
vehicles. For example, a diagnostic device 
which plugs in to a certain type of fuel 
injection ECU
Accuracy
Careful and exact, free from mistakes 
or errors and adhering closely to a 
standard

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