Fluke 78 User manual

®
78
Automotive Meter
Users Manual
For IEC 61010 CAT II Meters Only
PN 666625
November 1998 Rev.1, 9/00
© 1998, 2000 Fluke Corporation. All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies.

i
Table of Contents
Title Page
What is in the Manual.................................................................................................... 1
Using the Meter Safely.................................................................................................. 1
Getting Acquainted with the Meter................................................................................ 4
Rotary Switch ........................................................................................................... 4
Input Jacks ............................................................................................................... 6
Thermocouple Adapter............................................................................................. 6
Display...................................................................................................................... 8
RPushbutton....................................................................................................... 10
Standby (Sleep) Mode.............................................................................................. 10
Bar Graph................................................................................................................. 12
Autorange with "Floor".............................................................................................. 12
Typical Testing Applications.......................................................................................... 14
G,FHow to Measure Voltage................................................................................... 14
L
How to Test Diodes.......................................................................................... 16
N, AdHow to Measure Current.............................................................................. 18
wHow to Test Continuity........................................................................................ 20
JHow to Measure Resistance................................................................................. 22
RPM ut How to Measure RPM with the RPM80 Inductive Pickup (Optional)........ 24

78
Users Manual
ii
Hz sHow to Use DC-Coupled HZ to Check BP/MAP Sensors............................. 26
Hz dHow to Use AC-Coupled Hz on a Crankshaft Position Sensor .................... 28
mHow to Measure Dwell on Conventional Ignitions........................................... 30
% How to Measure Duty Cycle on a Feedback Carburetor...................................... 32
°C °F How to Measure Temperature on a Coolant Temperature Sensor.................. 34
How to Store Minimum and Maximum Measurements................................................... 36
How to Use the Bar Graph to Test a Throttle Position Sensor....................................... 38
How to Lock the Meter in a Measurement Range.......................................................... 40
Using the Holster and Flex-Stand.................................................................................. 40
Maintenance .................................................................................................................. 42
Cleaning.................................................................................................................... 42
Calibration................................................................................................................. 42
How to Test the Fuse................................................................................................ 42
How to Replace the Battery or Fuse ......................................................................... 42
Accessories and Parts................................................................................................... 42
Specifications................................................................................................................. 46

iii
List of Tables
Table Title Page
1. Symbols ............................................................................................................................. 1
2. Measurement Unit Symbols............................................................................................... 8
3. Pushbutton Operations ...................................................................................................... 11
4. Replacement Parts and Accessories ................................................................................. 45

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Users Manual
iv

v
List of Figures
Figure Title Page
1. Rotary Switch..................................................................................................................... 5
2. Input Jacks......................................................................................................................... 7
3. Display ............................................................................................................................... 9
4. Interpreting the Bar Graph ................................................................................................. 13
5. Measuring No-Load Voltage of Battery.............................................................................. 15
6. Testing Diodes in Alternator Rectifier Bridge..................................................................... 17
7. Isolating Circuit Causing Current Drain.............................................................................. 19
8. Testing Continuity in a Switch............................................................................................ 21
9. Measuring Resistance to Check Coolant Temperature Sensor ......................................... 23
10. Measuring RPM with the (Optional) Inductive Pickup........................................................ 25
11. Checking Barometric Pressure/Manifold Absolute Pressure Sensor ................................. 27
12. Using AC Coupled-Frequency on a Crankshaft Position Sensor....................................... 29
13. Measuring Dwell on a Conventional Ignitions.................................................................... 31
14. Measuring Duty Cycle on a Feedback Carburetor............................................................. 33
15. Measuring the Temperature of Coolant Temperature Sensor............................................ 35
16. Using MIN MAX to Check an Oxygen Sensor.................................................................... 37
17. Using Bar Graph to Observe Sweep of Throttle Position Sensor (TPS)............................ 39

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vi
18. Holster and Flex-Stand.......................................................................................................41
19. Fuse Test............................................................................................................................ 43
20. Fuse and Battery Replacement.......................................................................................... 44
21. Replacement Parts............................................................................................................. 45

IGNITION/ENGINE
Coils
Computer Temp Sensors
Condensers (Capacitors)
Connectors
Contacts Set
Distributor Cap
Engine Speed
Feedback Carburetors
Fuel Injectors (Electronic)
Hall-Type Sensors
Idle Air Motors
MAF Sensor
Ignition Modules
Magnetic Pickups
MAP & BP Sensors
0 Sensors
Throttle Position Sensors
STARTING SYSTEM
Battery
Connectors
Interlocks (neutral safety switch)
Solenoids
Starters
Amps DC* Bar Graph Dwell Continuity
% Duty Cycle
HzMillivolts
MIN MAX Ohms
RPM** Volts AC Volts DC
* Used with Fluke 80i-410 or 80i-1010 current clamp.
** With optional RPM 80 Inductive Pickup accessory.
2
APPLICATIONS GUIDE
Temperature

COOLING SYSTEM
Connectors
Fan Motor
Radiator
Relays
Temperature Sensors
Temperature Switches
CHARGING SYSTEM
Alternators
Computerized Regulators
Connectors
Diodes, (AC Ripple)
Regulators
Diode Rectifier
BODY ELECTRIC
Compressor Clutch
Lighting Circuits
Relay and Motor Diodes
Transmissions
Amps DC*
Bar Graph Continuity
% Duty Cycle
HzMillivolts MIN MAX
Ohms
RPM **
Volts AC
Volts DC
* Used with Fluke 80i-410 or 80i-1010 current clamp.
** With optional RPM 80 Inductive Pickup accessory.
APPLICATIONS GUIDE (cont)
Temperature
Dwell

FUSED
10A
30V
°C°F
300V
30V
RPM
+
COM
V
CAT
RPM
21
1
Hz
MIN /MAX PRESS
OFF
A°C°F
HzV
Hz
V
78
AUTOMOTIVE METER
1 SEC
2 SEC
0 3 4000
AC DC
mV
Mk Hz
RPM
2
MIN
MAX V
AUTO
12
1
DISPLAY
BAR GRAPH
PUSHBUTTON
ROTARY SWITCH
INPUT JACKS
SKID RESISTANT PADS
PHILLIPS-HEAD SCREWS
SAFETY INFORMATION
FUSE RATING
BATTERY TYPE
BACK
WARNING
TO AVOID DAMAGE OR INJURY,
USE ONLY IN PROTECTED CIRCUITS WHICH
CAN NOT EXCEED 4800 VOLT-AMPS.
TO PREVENT FIRE, INSTALL FUSE WITH
AMP/VOLT RATINGS SHOWN.
TO AVOID ELECTRICAL SHOCK, REMOVE
TEST LEADS BEFORE OPENING CASE.
FLUKE CORPORATION
MADE IN USA
U.S. PATENTS: 4,556,867 4,532,470
F 15A 600V
MIN INTERRUPT RATING 10 000A
9V NEDA 1604
6F22 006P
FRONT

What is in the Manual
1
Warning
Read "Using the Meter Safely" before using
the meter.
Note
The automotive tests included in this manual are
intended to help you learn how to use the meter.
Consult your car’s service manual for specific
procedures that apply to your car.
What is in the Manual
This manual provides safety information, operating in-
structions, basic maintenance procedures, and specifica-
tions for the Fluke 78 Automotive Meter (referred to as
"the meter").
To contact Fluke, call one of the following telephone
numbers:
USA: 1-888-99-FLUKE (1-888-993-5853)
Canada: 1-800-36-FLUKE (1-800-363-5853)
Europe: [phone]
Japan: [phone]
Singapore: [phone]
Anywhere in the world: [phone]
Or, visit Fluke’s Web site at www.fluke.com
Refer to the 78 Service Manual (P/N 666617) for com-
plete servicing information. If the meter is damaged or
something is missing, contact the place of purchase im-
mediately.
Fluke Corporation P.O. Box 9090 Everett WA 98206-9090
Fluke Europe B.V. P.O. Box 1186 5602 B.D. Eindhoven, The Netherlands
Using the Meter Safely
Use the meter as described in this manual. Otherwise the
safety features provided by the meter might be impaired.
A Warning identifies conditions and actions that pose
hazards to the user; a Caution identifies conditions and
actions that might damage the meter. International elec-
trical symbols used on the meter are shown in Table1.
Table 1. Symbols
Symbol Meaning
Important information. See manual.
Alternating current (AC)
Direct current (DC)
Alternating or direct current (AC or DC)
Diode
Ground
Fuse
Double insulation (Protection Class II)
Conforms to European Union directives

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Users Manual
2
Read First: Safety Information
This meter complies with EN 61010-1:1993,
ANSI/ISA S82.01-1994 and CAN/CSA C22.2
No. 1010.1-92 Overvoltage Category II. Use
the meter only as specified in this Users
Manual, otherwise the protection provided by
the meter may be impaired.
Warning
To avoid possible electric shock or personal
injury:
•Avoid working alone.
•Do not use the meter if it is damaged.
Before use, inspect the case for cracks
or missing plastic. Pay particular atten-
tion to the insulation surrounding the
connectors.
•Inspect the test leads for damaged in-
sulation or exposed metal. Check test
lead continuity. Replace damaged leads.
•Do not use the meter if it operates ab-
normally. Protection may be impaired.
When in doubt, have the meter serviced.
•Do not operate the meter around explo-
sive gas, vapor or dust.
•Do not apply more than the rated volt-
age, as marked on the meter, between
terminals or between any terminal and
earth ground.
•Before each use, verify the meter’s op-
eration by measuring a known voltage.
•When servicing the meter, use only
specified replacement parts.
•Use caution when working above 30 V ac
rms, 42 V ac peak, or 60 V dc. Such volt-
ages pose a shock hazard.
•Keep your fingers behind the finger
guards on the probe when making
measurements.
•Connect the common test lead before
connecting the live test lead. Disconnect
the live test lead first.
•Remove test leads from the meter before
opening the case.

Using the Meter Safely
3
•Use only a single 9 V battery, properly
installed in the meter case, to power the
meter.
•Follow all equipment safety procedures.
•Before measuring current, check the me-
ter’s fuses (see “How to Test the Fuse”).
•Never touch the probe to a voltage
source when the test leads are plugged
into the 10 A input jack.
•Always use clamp-on probes (dc current
clamps) when measuring current ex-
ceeding 10 A.
•DO NOT connect thermocouple to volt-
ages exceeding 30 V.
•To avoid false readings, which could
lead to possible electric shock or per-
sonal injury, replace the meter’s battery
as soon as the low battery indicator (N)
appears.
Caution
To avoid possible damage to the meter or to
equipment under test:
•Disconnect the power to the circuit un-
der test and discharge all high voltage
capacitors before testing resistance,
continuity or diodes.
•Use the proper function and range for
your measurement applications.
•When measuring current, turn off circuit
power before connecting the meter in
the circuit. Remember to place the meter
in series with the current.

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Users Manual
4
Getting Acquainted with the Meter
Rotary Switch
Turn the rotary switch (Figure 1) from OFF to another
switch setting to turn the meter ON. The display lights for
1 second as part of a selftest routine. The meter is now
ready to take measurements.
Each switch setting has a primary AND an alternate func-
tion. Primary functions are in white; alternate functions
are in yellow.
To toggle between a primary and alternate function, hold
down the push-button for 2 seconds.

Getting Acquainted with the Meter
5
Hz
OFF
A°C°F
HzV
V
VOLTS AC OR AC-COUPLED HZ
VOLTS DC OR DC-COUPLED HZ
DWELL OR DUTY CYCLE
RPM (WITH OPTIONAL RPM 80)
RESISTANCE OR CONTINUITY TEST
TEMPERATURE OR DIODE TEST
AMPS DC OR AC
PUSHBUTTON (See Table 3)
RPM
21
mt01f.eps
Figure 1. Rotary Switch

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Users Manual
6
Input Jacks
Warning
To avoid personal injury or equipment dam-
age, never attempt a voltage measurement if
a test lead is in the 10A jack.
The meter has four input jacks (Figure 2) that are pro-
tected against overloads to the limits shown on the front
and back of the meter.
Thermocouple Adapter
Warning
To avoid possible electric shock or personal
injury, do not connect the thermocouple to
voltages exceeding 30 V.
The 80BK Thermocouple Adapter allows you to use a
thermocouple to measure temperature. If the adapter
gets lost or damaged, replace the adapter with a Fluke-
specified part (see Table 4) to ensure optimum perform-
ance of the thermocouple.
The meter measures temperature using Type-K thermo-
couple probes. This thermocouple is suitable for making
surface temperature measurements from -40°C
(or °F) to 260°C (500°F) in teflon-compatible environ-
ments.
Warning
To avoid personal injury or equipment dam-
age, do not use this thermocouple in liquids
or at temperatures above 260°C (500°F). At
these temperatures the teflon insulation can
emit toxic gases
.

Getting Acquainted with the Meter
7
FUSED
10A
30V
°C°F
300V
30V
RPM
+
COM
V
CAT
COM
RPM
AMPS (10 A CONTINUOUS, 20 A FOR <30 SEC)
OR COMMON FOR RPM COMMON (RETURN) JACK FOR VOLTS, OHMS, DIODE TEST, TEMPERATURE, DWELL.
DUTY CYCLE, CONTINUITY, AND HZ
VOLTS, OHMS, DIODE TEST,
DWELL, DUTY CYCLE,
TEMPERATURE, CONTINUITY
AND HZ
mt02f.eps
Figure 2. Input Jacks

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Users Manual
8
Display
Readings are shown on a liquid crystal display (LCD).
Symbols on the display indicate what the meter is doing.
See Figure 3 and Table 2.
If a measurement is too large to be displayed, OL (over-
load) is shown on the display and the whole bar graph
lights. Warning
To avoid false readings, which could lead to
possible electric shock or personal injury, re-
place the battery as soon as the battery indi-
cator (N) appears.
Table 2. Measurement Unit Symbols
Symbol Meaning
AC Alternating current or voltage
DC Direct current or voltage
VVolts
Hz Hertz (cycles/second). Frequency
RPM1 Revolutions/minute. 1 RPM count/spark
RPM2 Revolutions/minute. 2 RPM counts/spark
qDegrees Celsius
pDegrees Fahrenheit
oLNumber of Cylinder
% Percent (for duty cycle readings)
rDegrees of rotation (for dwell readings)
ΩOhms. Resistance
k Kilo. Units x 1,000
M Mega. Units x 1,000.000
m Milli. Units x 1/1,000