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

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Users Manual
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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
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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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Users Manual
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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