Automotive Meter
Contents
1. Hz How to Use AC Coupled Hz on a Crankshaft Position Sensor 2 How to Measure Dwell on Conventional How to Measure Duty Cycle on a Feedback C F How to Measure Temperature on a Coolant Temperature Sensor How to Store Minimum and Maximum nene How to Use the Bar Graph to Test a Throttle Position Sensor How to Lock the Meter in a Measurement Range Using the Holster and Flex Stand Maintenance PEE How to Test the How to Replace the Battery or Accessories and 7 Specifications il List of Tables Table Title Page 1 2 Measurement Unit Symbols U u u 8 3 Pushbutton Operations sss nennen nennen nennen nnns 4 Replacement Parts and Accessories 0 8 iii 78 Users Manual iv List of Figures Figure Title 1 Rotary SWICK ayu a qua aa ere ea deen 2 jeudi cM 3 Display u2. Fuse Test Fuse and Battery Replacement Replacement Parts vi APPLICATIONS GUIDE 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 Ignition Modules MAF Sensor Magnetic Pickups MAP 8 Sensors 02 Sensors Throttle Position Sensors STARTING SYSTEM Battery Connectors Interlocks neutral safety switch Solenoids Starters Used with Fluke 80i 410 or 80i 1010 current clamp With optional RPM 80 Inductive Pickup accessory APPLICATIONS GUIDE cont COOLING SYSTEM Connectors Fan Motor Radiator Relays Temperature Sensors Temperature Switches CHARGING SYSTEM Alternators Computerized Regulators Connectors Diodes AC Ripple Diode Rectifier Regulators BODY ELECTRIC Compressor Clutch Lighting Circuits Relay and Motor Diodes Transmissions Used with Fluke 80i 410 or 80i 1010 current clamp With optional RPM 80 Inductive Pickup accessory ES 78 AUTOMOTIVE METER 1888882 DISPLAY BAR GRAPH 0 MAX 1 MN 2 PUSHBUTTON ROTARY SWITCH MIN MAX Hz ril gt INPUT JACKS j
3. Note When measuring frequency in VDC the meter displays frequency on the digital display The bar graph is turned off and the meter ranging is manual only Typical Testing Applications HARNESS CONNECTOR FLUKE 78 AUTOMOTIVE METER Aaa 15802179 WA 1 GROUND Q TL26 CLIPS Press for JUMPER WIRES s 2 seconds TO VACUUM way PUMP SIN NI SENSOR 55 MIN MAX Hz inj mt11f eps Figure 11 Checking Barometric Pressure Manifold Absolute Pressure Sensor 27 78 Users Manual Hz How to Use AC Coupled Hz on a Crank shaft Position Sensor Use the ac coupled Hz function on parts like crankshaft position or vehicle speed sensors The following procedure demonstrates how to measure ac coupled frequency to test a crankshaft position sensor 1 Insert the test leads in the jacks Figure 12 2 the rotary switch to Hz 3 Press C for 2 seconds to toggle between the volts ac and frequency functions AC and Hz show on the display when ac coupled frequency is selected 4 Connect the test leads to the jumper wires 28 KEY ON ENGINE OFF Disable the engine ignition Crank the motor while watching the display Note When measuring frequency the meter displays frequency on the digital display and shows the voltage of the input signal on the bar graph This allows you to see if a
4. tio gt 60 dB dc to 60 Hz Full Scale Voltage To 4 0 MQ 40 MQ Common Mode Rejection Ra gt 120 dB at dc 50 Hz or 60 Hz 2 500 V dc 450 mV dc 1 3 V dc Normal Mode Rejection Ratio gt 60 dB at 50 Hz or 60 Hz Short Circuit Current 500 uA 1 6 mA typical Specifications When measuring temperature the accuracy of the system is the combined accuracy of the meter and the thermocou 980 C below 20 C ambient Function Range Resolution Accuracy Frequency 99 9 0 01 Hz 0 01 2 1 Hz to 20 kHz 999 9 0 1 Hz 0 01 2 9 999 0 001 kHz 0 01 2 7 20 00 2 0 01 2 0 01 2 10 V Hz maximum 20 00 kHz to 99 99 kHz 0 01 kHz Usable 500 0 kHz 0 1 kHz Usable RPM1 60 7 000 RPM useable to 9 999 1 RPM 0 2 2 RPM RPM2 dequo RPM useable to 1 RPM 0 2 2 RPM Dwell Angle 0 120 1 degree 2 degrees Duty Cycle 0 0 99 996 0 196 0 2 per kHz 0 196 1 Hz to 20 kHz pulse width gt 5 us for rise time 1 us Temperature 40 to 999 C 9 gt 20 C ambient to 1 degree 0 3 6 C 40 to 20 C 0 396 4 C 20 to 0 C 0 3 Bx 0to 170 C 0 3 5 C 170 to 260 C 0 3 6 C 260 to 700 C 0 3 7 C 700 to 999 C HE IB PE ple Frequency Counter Sensitivity and Trigger Level Input Range Minimum Sensitivity rms Sine Wave Approximate Trigger level DC Volts Function 1 Hz to 5 Hz 5
5. polarity with a minus sign The no load voltage only indicates the state of charge not the condition of the battery Note Use the V function to measure ripple voltage at the rear of the alternator not the battery With the engine running a good alternator measures less than 0 5 V ac A higher reading indicates damaged alternator diodes Typical Testing Applications FLUKE 78 AUTOMOTIVE METER A fully charged battery typically shows about 12 6 V See other typical values in table below at 27 C 80 F Voltage Charge 12 60 V 100 12 45 75 12 30 V 50 12 15 25 LIGHT CIRCUIT C F gt PRESS MIN MAX Hz DLC A Ow A ED mtO5f eps Figure 5 Measuring No Load Voltage of Battery 15 78 Users Manual How to Test Diodes 4 Reverse the probes and measure the voltage across the diode again Caution e Ifthe diode i d OL is displayed To avoid possible damage to the meter or to alae hes SUP the equipment under test disconnect circuit e Ifthe diode is shorted near 0 V drop is displayed power and discharge all high voltage capaci in both directions and the beeper sounds con tors before measuring resistance testing for tinuously continuity or diode test e Ifthe diode is open OL is displayed in both di A good diode allows current to flow in one direction only rections To test a diode turn the power off remove the diode from Figure 6 sh
6. Hz to 20 kHz 400 0 mV dc 400 mV 4000 mV dc 400 mV 4 000 V 0 7 V 03 V 1 7 V 40 00 V 7V 3V 4V 300 0 V 70 V 30 V 40 V 49 78 Users Manual 50
7. Manually changes amps dc range Toggles in and Toggles between A out of MIN MAX amps DC and amps mode AC 11 78 Users Manual Bar Graph The bar graph shows readings relative to the full scale value of a measurement range For example if the meter is in the 4V range the scale goes from 0 4 and each number on the bar graph scale represents 1 V If the meter is in the 40V range the scale goes from 0 40 and each number on the scale rep resents 10 V The range is indicated by a number at the right of the bar graph polarity is indicated by a plus or minus sign at the left See Figure 3 The bar graph turns off when the meter is measuring RPM duty cycle dwell temperature or frequency in the VDC mode When measuring frequency in the VAC mode the meter displays frequency on the digital display and shows the voltage of the input signal on the bar graph This allows you to see if a hazardous AC voltage is pres ent Some examples of digital readings and their equivalents on the bar graph are shown in Figure 4 12 Autorange with Floor For most applications simply select a function and make the measurement The meter autoranges to the best range for the input signal and displays a reading Most functions have more than one range see SPECIFICATIONS The range is shown at the right of the bar graph Note In MIN MAX autorange is disabled See How to Use MIN MAX Each ra
8. Service Manual PN 666617 How to Test the Fuse Test the meter s fuse as shown in Figure 19 How to Replace the Battery or Fuse N 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 appears To avoid electric shock or personal injury e Do not allow water to get inside case e Remove any input signals prior to re moving test leads and opening case e When servicing the meter use ONLY specified replacement parts See Table 4 for part numbers e Replace fusible resistor R1 ONLY with specified replacement part e Install only specified replacement fuses 42 Caution To avoid damaging components do not lift the battery straight out Lift the end of the battery as shown in Figure 20 Replace the battery and fuse as shown in Figure 20 The meter uses a 9 V battery and a F15 A 600 V fuse To avoid contamination or static damage do not touch the rotary switch or circuit board For safety replace the fuse only with a fuse having a minimum interrupt rating of 10 kA Fluke Part No 820829 Do not bypass the fuse Accessories and Parts Note When servicing the meter use only the replace ment parts specified in Table 4 Replacement parts are shown in Figure 21 Parts and ac cessories are listed in Table 4 To contact Fluke call one of the following telephone num bers USA 1 888 99 FLUKE 1 88
9. coolant temperature sensor 1 Plug the adapter with thermocouple into the jacks as shown in Figure 15 2 Turn the rotary switch to C F To toggle between Fahrenheit and Celsius press C 2 momentarily 3 Attach the thermocouple to the sensor 4 Read the display If the meter detects an open or no thermocouple the display flashes the internal temperature of the meter Typical Testing Applications A Warning FLUKE 78 AUTOMOTIVE METER To avoid electrical shock do not use the thermocouple when voltages exceeding 30 V rms or 30 V dc are present Note The thermocouple adapter and meter must be at the same temperature for accurate measurements If at different temperatures plug together and wait up to 15 minutes MOMENTARY PRESS TO TOGGLE BETWEEN FAHRENHEIT AND CELSIUS THERMOCOUPLE s ADAPTER 10 30V TEMPERATURE SENSOR mt15f eps Figure 15 Measuring the Temperature of Coolant Temperature Sensor 35 78 Users Manual How to Store Minimum and Maximum Measurements The MIN MAX function stores the lowest and highest measurements made by the meter In MIN MAX auto ranging and standby are disabled To use MIN MAX Note During MIN MAX operation the beeper will sound continuously if an overrange O L condition is detected except in Diode test 1 Put the meter in a measurement function 2 When you put the meter in MIN MAX you also lock the meter in its present
10. through your local distributor gure p To ensure safety use exact replacement only 45 78 Users Manual Specifications Accuracy is specified for a period of one year after calibration at 18 C to 28 C 64 F to 82 F with relative humidity to 90 AC conversions are ac coupled average responding and calibrated to the rms value of a sine wave input Accuracy speci fications are given as of reading number of least significant digits Safety Approvals Maximum Voltage Between any Terminal and Earth Ground Fuse Protection Display Operating Tempera ture Storage Temperature Temperature Coeffi cient Relative Humidity Electromagnetic Compatibility Battery Type Battery Life Continuity Beeper Shock Vibration Altitude Size HxWxL Weight Safety 46 300 V 15 600 V FAST Fuse Digital 4000 counts updates 4 s Bar Graph 64 segments update rate 40 s Frequency 9 999 counts updates 3 s 0 to 55 C 32 F to 131 F EMI Regulation 40 to 60 C 40 F to 140 F 0 1 x specified accuracy per C ambient lt 18 C or gt 28 C When measuring temperature 0 04 0 1 C per C 0 to 95 to 30 C 86 F 0 to 75 to 40 104 F 0 to 45 to 55 C 131 F In an RF field of 1 V m on all ranges and functions Total Accuracy Specified Accuracy 0 7 of range Performance above 1 V m is not specified 9 V NEDA 1604 or 6F22 or 006 Al
11. to the sensor as shown Slowly open the throttle while watching the bar graph As the resistance increases the bar graph moves slowly if the TPS is good and moves erratically if the TPS is bad Note With some sensors the resistance increases above the 4 k range when the throttle opens If this occurs the meter autoranges to a higher range causing the bar graph to wrap This does not mean that the TPS is bad How to Use the Bar Graph to Test a Throttle Position Sensor TPS CONNECTOR FLUKE 78 AUTOMOTIVE METER 3 n A P 10 4 Lath OL A OU 4 mt17f eps Figure 17 Using Bar Graph to Observe Sweep of Throttle Position Sensor TPS 39 78 Users Manual How to Lock the Meter in a Measurement Range The measurement range determines the highest input the meter can measure Most meter functions have more than one range See SPECIFICATIONS For most applications you can let the meter s autorange function select the best range for the input signal How ever you can disable autorange and lock the meter in a specific range as follows 1 Putthe meter in the desired function 2 Press momentarily to step up a range The range indicator at the right of the bar graph changes When measuring resistance short the test leads to see the range changes Notice that the decimal point moves changing the resolution of the displayed reading Each press st
12. 8 993 5853 Canada 1 800 36 FLUKE 1 800 363 5853 Europe 31 402 678 200 Japan 81 3 3434 0181 Singapore 65 738 5655 Anywhere in the world 1 425 446 5500 Or visit Fluke s Web site www fluke com Accessories and Parts 10 05 Q Gi mt19f eps Figure 19 Fuse Test 43 78 Users Manual 44 Figure 20 Fuse and Battery Replacement mt20f eps Accessories and Parts Table 4 Replacement Parts and Accessories Description Fluke PN Qty BT1 9 V Battery 0 15 mA 696534 1 F1 A Fuse F15 A 600 V Min 820829 1 Interrupt Rating 10 kA H7 10 Screw Case 733410 4 MP1 LCD Window Fluke 78 919717 1 R1 Resistor Fusible 1k 2W 832550 1 TM1 78 Users Manual English 666625 1 TM2 78 Users Manual European 666628 1 TM3 Fluke 78 Quick Reference Card 926915 1 TM4 78 Service Manual 666617 1 80BK Thermocouple Adapter 1 AC70 Alligator Clips 1 set 1 TL75 Test Leads Right Angle One Set 1 C70Y Yellow Holster 1 AC85 Large Jaw Alligator Clips 89 Insulation Piercing Clip RPM80 Inductive Pickup TL20 Industrial Test Lead Set TL24 Silicone Insulated Test Leads TL26 5 Way Multipoint Test Lead Set To ensure safety replace the R1 fusible resistor only with this Fluke mi2tieps specified part Figure 21 Replacement Parts Accessory that is normally available
13. FLUKE 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 Table of Contents Title Page What is in the Using the Meter Safely uu unn i n te eas un reco EE e dean Getting Acquainted with the 2 Rotary SWITH uuu aa geile c Thermocouple Adapter repe E RC ep e E eee cerei iore DISPLAY emp t Standby Sleep Mode u Bal Gra eL Autorange with Typical Testing Applications u u V V How to Measure Voltage ccccscsscsscsscssccsecsecsecsscsecsecsseeecaecsecsecsecesnseeaseasens gt Howto Test Diodes oni A How to Measure to Test CONtUAUILY aun eerie er eme e tes How to Measure Resistance RPM How to Measure RPM with the RPM80 Inductive Pickup Optional 78 Users Manual Hz L How to Use DC Coupled HZ to Check BP MAP Sensors
14. SKID RESISTANT PADS e PHILLIPS HEAD SCREWS A WARNING E SAFETY INFORMATION O AVOID DAMAGE OR INJU USE ont IN PROTECTED CIRCUIT WHICH T EXCEED 4800 VOLT 16 PREVENT FIRE INSTALL FUSE Wii OLT RATINGS SH TO AVOID ELECTRICAL SHOCK V REMOVE TEST EER OPENING CASE FUSE RATING BATTERY TYPE 9V NEDA 1604 6F22 006P FLUKE CORPORATION MADE IN USA U S PATENTS 4 556 867 4 532 470 BACK What is in the Manual A 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 31 402 678 200 Japan 81 3 3434 0181 Singapore 465 738 5655 Anywhere in the world 1 425 446 5500 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 Ever
15. WIRES Press for 2 seconds CHASSIS GROUND mt14f eps Figure 14 Measuring Duty Cycle on a Feedback Carburetor 33 78 Users Manual C F How to Measure Temperature on a Coolant Temperature Sensor The Fluke 80BK Thermocouple Adapter that comes with the meter is suitable for making temperature measure ments from 40 or F to 260 C 500 in teflon compatible environments A Warning Above this temperature toxic gas might be emitted Do not immerse this thermocouple in liquids For best results use the thermocouple probe designed for each application i e an immersion probe for liquid or gel an air probe for air measurements etc and follow the measuring techniques below e Clean the measurement surface and make sure the probe is attached securely to the surface e When measuring above ambient temperatures move the thermocouple on the surface until you get the highest temperature reading e When measuring below ambient temperatures move the thermocouple on the surface until you get the lowest temperature reading 34 e When measuring near ambient temperatures take the reading when the display is most stable Excessive voltage and strong low frequency and radio frequency fields can reduce the accuracy of temperature readings Caution Do not sharply bend the thermocouple leads Repeatedly bending the leads can break them To measure temperature of a
16. e meter reading is too high or is unstable press the pushbutton momentarily to put the meter in the 40 V trigger range i e change the trigger level If necessary TO DISTRIBUTOR SPARK PLUG WIRE SPARK PLUG PRESS Hz dil gt r NU A pe rm A INDUCTIVE PICKUP OUTPUT PLUG mt10f eps Figure 10 Measuring RPM with the Optional Inductive Pickup 25 78 Users Manual Hz How to Use DC Coupled HZ to Check BP MAP Sensors Use the dc coupled Hz function for pulsed dc tests on parts like a mass air flow MAF sensor a manifold abso lute pressure MAP sensor or a Hall sensor The following procedure demonstrates how to measure dc coupled frequency to test a barometric pres sure manifold absolute pressure BP MAP sensor 1 2 3 26 Insert the test leads into the jacks Figure 11 Turn the rotary switch to Hz L Press C for 2 seconds to toggle between the volts dc and frequency function DC and Hz show on the display when dc coupled frequency is selected Connect the test leads to the jumper wires With the ignition KEY ON but the ENGINE OFF pump the vacuum up with a hand vacuum pump Watch the frequency change on the display Compare the frequency at various vacuum readings with the specifications in your car s service manual At 0 inches of Hg frequency should match the specifica tion for your altitude
17. easuring Dwell on a Conventional Ignitions lg BREAKER POINT LUN mt13f eps 31 78 Users Manual How to Measure Duty Cycle on a Feedback Carburetor Duty cycle is the percentage of time 0 99 9 a voltage is positive or negative Most cars have points closed for a duty cycle of 50 to 70 or mixture control solenoids that are set to 50 in closed loop To measure duty cycle on a feedback carburetor 1 Insert the test leads in the jacks as shown in Figure 14 2 Turn the rotary switch to 96 3 Press for 2 seconds to toggle to duty cycle When the meter is turned on or comes out of standby Sleep mode the trigger slope is negative The slope is indicated by a or sign at the left of the bar graph To toggle between a positive and negative trigger slope press C O momentarily 32 Connect the black test lead to ground and the red lead to the green mixture control test connector GM cars at the base of the carburetor Start the engine and read display when the engine is cold open loop When the engine is in open loop duty cycle is a steady value See the car s specifications Read the display again when the engine is warm closed loop When the engine warms up and goes into closed loop the reading duty cycle should fluctuate but av erage 50 Typical Testing Applications FLUKE 78 AUTOMOTIVE METER 12 V SUPPLY SIGNAL 5 Q JUMPER
18. eps up a range After the highest range the meter wraps to the lowest range 40 3 When the desired range is selected press C for 1 second to lock the meter in that range Note This also puts you in MIN MAX mode in which the meter stores the minimum and maximum readings See How to Use MIN MAX ear lier in this manual 4 display the present reading press C twice Both MIN and MAX blink when the present reading is displayed 5 To exit MIN MAX and resume autoranging press C O for 1 second or turn the rotary switch Using the Holster and Flex Stand The snap on holster with Flex Stand Figure 18 absorbs shocks and protects the meter from rough handling To protect the meter when stored in your toolbox put the meter in the holster face down Using the Holster and Flex Stand HOLSTER WITH FLEX STAND BENT HOLSTER WITH PROBE IN CLIP HOLSTER WITH FLEX STAND EXTENDED METER IN HOLSTER FACE DOWN HOLSTER WITH FLEX STAND FOR PROTECTION HOLSTER WITH FLEX STAND LOOPED OVER CAR DOOR Store Quick Reference Card Under Meter LOOPED OVER BELT mt18f eps Figure 18 Holster and Flex Stand 41 78 Users Manual Maintenance Cleaning Periodically wipe the case with a damp cloth and deter gent do not use abrasives or solvents Calibration Calibrate the meter yearly to ensure that it meets its per formance specifications Calibration and performance test procedures are in the 78
19. es 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 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 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 e 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 E ap
20. ett 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 Table 1 Table 1 Symbols Important information See manual Alternating current AC P Direct current DC Alternating or direct current AC or DC 4 Ground Fuse 5 Double insulation Protection Class II rN Conforms to European Union directives Diode 78 Users Manual 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 Il Use the meter only as specified in this Users Manual otherwise the protection provided by the meter may be impaired A 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 operat
21. few minutes U Press the pushbutton for 1 second to enter the MIN mode Let the engine run for a few minutes to allow the meter to record enough readings Press the pushbutton to display the minimum reading press again to display the present reading press again to display the maximum reading FLUKE 78 AUTOMOTIVE METER OOO EXHAUST MANIFOLD N 5011 gt PRESS CHASSIS GROUND O2 LAMBDA SENSOR mt16f eps Figure 16 Using MIN MAX to Check an Oxygen Sensor 37 78 Users Manual How to Use the Bar Graph to Test a Throttle Position Sensor The bar graph shows readings relative to the full scale value of the measurement range The range is shown at the right of the bar graph For example if the meter is in the 4V range the num bers on the bar graph scale represent 0 1 2 3 and 4 V If the meter is in the 40V range these same num bers represent 0 10 20 30 and 40 V Note When measuring frequency the meter displays frequency on the digital display and shows the voltage of the input signal on the bar graph This allows you to see if a hazardous voltage is pres ent To use the bar graph to observe the sweep on a throttle position sensor TPS 1 Insert the test leads in the jacks Figure 17 2 Turn the rotary switch to Q 38 With KEY OFF ENGINE OFF disconnect the TPS s electrical connector Then connect the test leads
22. gles to the continuity test function and 91 is displayed 5 Touch the probes to the circuit Continuity exists if resistance is less than about 30 ohms and the beeper emits a continuous tone Figure 8 shows how to use the continuity test to check a stoplight switch Typical Testing Applications 1 Insert test leads in the jacks shown Turn rotary switch to continuity test FLUKE 78 AUTOMOTIVE METER 3 Press pushbutton for 2 secs is displayed mr 4 Clip leads to switch as shown Li ao Press brake pedal and listen for tone If tone sounds stoplight switch is good TYPICAL STOPLIGHT SWITCH Q BRAKE PEDAL VA S m for CS PIVOT POINT 4 27 2 seconds lt reuse 2 lt E v 272 7 FEMALE gt es N gt N C F RED PRESS MIN MAX Hz G al gt GE RPM SILO A wa A OM Gr 0 BRAKE PEDAL mt08f eps Figure 8 Testing Continuity in a Switch 21 78 Users Manual How to Measure Resistance Resistance hinders the flow of current Caution To avoid possible damage to the meter or to the equipment under test disconnect circuit power and discharge all high voltage capaci tors before measuring resistance testing for continuity or diode test The following procedure demonstrates how to use the re sistance function using a coolant temperature sens
23. hazardous voltage is pres ent Typical Testing Applications FLUKE 78 AUTOMOTIVE METER ERER Q OFF V Hz Press for 2 seconds zx s 9 RPM GOD JUMPER WIRES Figure 12 Using Coupled Frequency on a Crankshaft Position Sensor mt12f eps 29 78 Users Manual lt How to Measure Dwell on Conventional Igni tions Dwell is the number of degrees of distributor rotation that the points remain closed or magnetic saturation time The following procedure demonstrates how to measure dwell on conventional ignitions 1 2 30 Insert the test leads into the jacks Figure 13 Turn the rotary switch to 27 The meter is in the dwell function The display shows and OL The meter defaults to 4 cylinders when the meter turns on or comes out of standby mode Press C momentarily to step through the number of cylinders 5 6 8 3 and back to 4 The meter displays the number of cylinders followed by Clip the black lead to ground and the red lead to the distributor side of the coil as shown in Figure 13 Start the car Read the display Dwell is displayed in degrees Note The wider the point gap the less the dwell the narrower the point gap the greater the dwell Typical Testing Applications NUMBER OF CYLINDERS MOMENTARY PRESS TO SELECT NUMBER OF CYLINDERS IGNITION SWITCH AND CIRCUIT BATTERY COIL ASSEMBLY Figure 13 M
24. ifier Bridge 17 78 Users Manual A A How to Measure Current A Warning To avoid electric shock or personal injury e Never attempt an in circuit current meas urement where the open circuit potential to earth is greater than 300 V e Before measuring current check the me ter s fuses see How to Test the Fuse e Turn off circuit power before connecting the meter in the circuit Remember to place the meter in series with the current e Use proper terminals function and range for your measurement e Always use clamp on probes dc current clamps for circuits of more than 10 A Install ONLY specified replacement fuses Current is the flow of electrons through a conductor To measure current 18 1 Turn off power to the circuit and break the circuit To measure current without breaking the circuit use a current clamp 2 Insert the test leads into the 10 A and COM jacks 3 Turn the rotary switch to A To toggle to A press C for 2 seconds 4 Clip the red test lead to the side closest to the power source and clip the black test lead to the side closer to ground This puts the meter in series with the circuit being tested and all current flows through the meter Always measure current with the meter in series with the cir cuit under test 5 Turn ON power to the circuit and read the display Figure 7 shows how to isolate a circuit causing current drain Typical Testing Applicatio
25. kaline 500 hrs typical Carbon zinc 300 hrs typical 4096 Hz Per MIL T 28800 for a Style D Class 3 Instrument Inductive Pickup Thermocouple 2000 meters 6562 feet 1 12 in x 2 95 in x 6 55 in 2 8 cm x 7 5 cm x 16 6 cm 12 oz 340g Complies with ANSI ISA S82 01 1994 CAN CSA 22 2 No 1010 1 1992 to 300 V Overvoltage Category Il UL license pending to UL3111 1 TUV License to EN61010 1 MIN MAX Recording CSA Certified TUV Product Service licensed UL Complies with FCC Part 15 Class B VDE 0871B Vfg 243 1991 This device complies with part 15 of the FCC rules Operation is subject to the following two conditions 1 This device may not cause harmful interference and 2 this device must accept any interference re ceived including interference that may cause unde sired operation Input Magnetic field from sparkplug Output Pulse to trigger Fluke 78 Type K Chromel vs Alumel Not suitable for immersion in liquid Accuracy 1 1 C 2 F between 0 C to 260 C 32 F 500 F Typically within 1 1 C 2 F of NBS tables for tem peratures between 40 C 40 F to 0 C 32 F Temperature Range 40 C to 260 C 40 F to 500 F Above 260 C 500 F toxic gas might be emitted NOTE The temperature range is primarily a function of the thermal limitations of the thermocouple s insula tion Cable Insulation Teflon Accuracy Specified accuracy of measurement func tion 16 digits for change
26. kup Unplug the RPM80 from the meter before measuring voltages above 30 V Insert the pickup plug into the jacks shown in Figure 10 Make sure the end of the plug is in the RPM jack Turn the rotary switch to RPM 22 The meter has two RPM functions e Use RPM 2 for engines that fire once every two revolutions e Use RPM 1 for engines that fire every revolution or for waste spark distributorless ignition sys tems DIS ie 1 RPM count spark Spread the spark plug wires apart Clamp the induc tive pickup to a plug wire near the spark plug In general the longest wire works best Make sure that the jaws are closed completely and the side labeled SPARK PLUG faces the spark plug Start the engine RPM is displayed turn OFF the engine and re verse the inductive pickup so that the side labeled SPARK PLUG faces AWAY from the spark plug Start the engine To toggle between RPM 2 and RPM 1 press C D for two seconds The display shows RPM 2 or RPM 1 depending on the function selected Read RPM on the display TURN OFF THE ENGINE Remove the pickup Typical Testing Applications Warning The ignition system can create a potential shock hazard turn the engine off before connecting or removing PEKE 78 4 the pickup Caution The Pickup might be hot if it has been near the exhaust manifold and the engine has been running TIN TRIGGER Note RANGE If th
27. n MIN MAX press to display maximum minimum or present readings Switch Momentary Press lt 1 sec Press and Hold Press and Hold Position for 1 sec for 2 sec H Manually changes range Toggles in and Toggles between Z v V In MIN MAX press to display maximum minimum or present readings Olt of MAIN MAX volts AC and AC mode coupled frequency nz Manually changes range Toggles in and Toggles between 2 E V In MIN MAX press to display maximum minimum or present readings out of MIN MAX volts DC and DG mode coupled frequency In dwell steps through number of cylinders 4 5 6 8 and 3 Toggles in and Toggles between aA In duty cycle toggles between negative and positive trigger out of MIN MAX dwell and duty cycle slope mode In MIN MAX press to display maximum minimum or present readings Manually changes trigger range i e toggles between two trigger levels Toggles in and Toggles between 1 M out of MIN MAX RPM count spark RPM In MIN MAX press to display maximum minimum or present readings mode RPM1 and 2 RPM counts spark RPM2 Qa Manually changes range Toggles in and Toggles between In MIN MAX press to display maximum minimum or present readings MIN MAX ohms and continuity eC F Toggles between degrees Celsius and degrees Fahrenheit Toggles in and Toggles between In MIN MAX press to display maximum minimum or present readings Our MIN MAX temperature and di mode ode test
28. nge has a floor The meter autoranges above the floor but not below it To determine the floor short the test leads the floor is shown at the right of the bar graph When using Fluke accessories like a dc current clamp or pressure sensor you may want to lock the meter in a mil livolt range in which 1 mV equals 1 unit of measurement e g for pressure measurements 1 mV could equal 1 psi See How to Lock the Meter in a Measurement Range Getting Acquainted with the Meter 250 V DC ON 300 V RANGE OVERLOAD mt04f eps Figure 4 Interpreting the Bar Graph 78 Users Manual Typical Testing Applications V V How to Measure Voltage Voltage is the difference in electrical potential charge between two points The following procedure demonstrates how to measure voltage using the example of the no load voltage of a battery 1 Insert the test leads into the jacks Figure 5 2 Turn the rotary switch to V A Warning To avoid personal injury or damage to equipment never attempt a voltage meas urement with a test lead in the 10 A input ter minal Turn the car lights on for 1 minute to bleed off surface charge then turn lights off 14 Touch the probes to the circuit This puts the meter in parallel with the circuit Voltage must be measured with the meter in parallel with the circuit Read the voltage If you reverse the probes when measuring dc voltage the display indicates negative
29. ns A Warning Do not attempt this test on a lead acid battery that has recently FLUKE 78 AUTOMOTIVE METER been recharged Explosive gases might be present 1 Caution Do not crank the engine or operate accessories that draw more than 10 A You could blow the fuse in the meter Note Many computers draw 10 mA or more continuously 1 Insert test leads in the jacks shown Turn the rotary switch to dc amps Disconnect battery terminal and touch probes as shown Isolate circuit causing current drain by pulling out one fuse at a time while reading the display Current reading will drop when the fuse on the bad circuit is pulled 3 mus DO NOT OPERATE STARTER mt07f eps Figure 7 Isolating Circuit Causing Current Drain 19 78 Users Manual x1 How to Test Continuity Caution To avoid possible damage to the meter or to the equipment under test disconnect circuit power and discharge all high voltage capaci tors before measuring resistance testing for continuity or diode test A continuity test verifies that you have a closed circuit The meter detects opens or shorts lasting as little as 1 ms This is valuable when troubleshooting intermittents asso ciated with cables connectors switches relays etc To check continuity 1 Turn off power to the circuit 2 Insert the test leads into the 4 and COM jacks 3 Tum the rotary switch to 9 20 4 Press C for 2 seconds The meter tog
30. on the display indicate what the meter is doing See Figure 3 and Table 2 Ifa measurement is too large to be displayed OL over load is shown on the display and the whole bar graph lights A 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 E appears Table 2 Measurement Unit Symbols Symbol AC DC V Hz RPM1 RPM2 d x R Meaning Alternating current or voltage Direct current or voltage Volts Hertz cycles second Frequency Revolutions minute 1 RPM count spark Revolutions minute 2 RPM counts spark Degrees Celsius Degrees Fahrenheit Number of Cylinder Percent for duty cycle readings Degrees of rotation for dwell readings Ohms Resistance Kilo Units x 1 000 Mega Units x 1 000 000 Milli Units x 1 1 000 Getting Acquainted with the Meter ER L CELSIUS OVERLOAD FAHRENHEIT REPLACE BATTERY DE AUTOMOTIVE METER AND DIODE TEST NE FLUKE 78 BAR GRAPH POLARITY OR ri r cl are s UNITS TRIGGER SLOPE FOR LA 5 Ea See Table 2 DUTY CYCLE AND DWELL Ca MAX 3 3000 aie Anni den NE MEASUREMENT RANGE OR RANGE FLOOR BOTH FLASH FOR MAXIMUM READING AUTORANGE ENABLED PRESENT READING MINIMUM READING BAR GRAPH SCALE 0 1 2 3 4 BAR GRAPH mt03f eps Figure 3 Di
31. or Figure 9 as an example 1 Insert the test leads into the and COM jacks 2 the rotary switch to Q 3 Touch the probes to the circuit Make sure that you have a good contact between the probes and the cir cuit Dirt oil or other foreign matter affects the resis tance 4 Read the display 22 Notes on Measuring Resistance The resistance shown on the display is the total resistance through all possible parallel paths between the probes This means that the resis tance displayed for an in circuit resistor can sometimes not correspond to its ohms value Resistance in standard test leads is about 0 1 to 0 2 When measuring low resistances this might be significant and should be subtracted from the display reading Typical Testing Applications FLUKE 78 AUTOMOTIVE METER S RADIATOR esos 254 7 p A toa Lat SL A OW FUSED 2 TEMPERATURE SENSOR mt09f eps Figure 9 Measuring Resistance to Check Coolant Temperature Sensor 23 78 Users Manual RPM 22 How to Measure RPM with the RPM80 Inductive Pickup Optional The RPM80 Inductive Pickup converts the magnetic field created by the current in the spark plug wire to a pulse that triggers an RPM measurement To measure RPM using the pickup 24 A Warning Because the ignition system creates a shock hazard turn off the engine before connecting or removing the inductive pic
32. ows how to check the diodes in an alternator the circuit and proceed as follows rectifier bridge 1 Insert the test leads into the and COM jacks 2 Turn the rotary switch to gt and press C for 2 seconds The meter toggles to the diode test function and 0111 is displayed on the LCD 3 Touch the red probe to the positive side of the diode and the black probe to the negative side The meter displays voltage to approximately 2 5 V Typical voltage drop for a silicon diode is less than 0 7 V and causes the meter to beep 16 Typical Testing Applications Insert the test leads as shown Turn the rotary switch to diode test FLUKE 78 AUTOMOTIVE METER Press the pushbutton for 2 seconds to toggle to the diode test function Touch the red test probe to a diode contact touch the black to ground 4 2 Typical voltage drop is 0 5 0 8 V and causes the meter to beep Some diodes may drop 0 3 V Reverse the probes If the diode is Good the display shows OL Shorted the display shows near 0 in both directions 3 4y Open the display shows OL in both directions Repeat steps 4 and 5 for the other diodes Press for RECTIFIER BRIDGE 2 seconds DIODE CONTACTS CI rri Cet A 300V V CRI Le cube A FUSED GROUND minimax B Hz T gt re O mt06f eps Figure 6 Testing Diodes in Alternator Rect
33. pears Caution To avoid possible damage to the meter or to equipment under test e Disconnect the power to the circuit un der test and discharge all high voltage capacitors before testing resistance continuity or diodes e Use the proper function and range for your measurement applications e When measuring current turn off circuit power before connecting the meter in the circuit Remember to place the meter in series with the current 78 Users Manual 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 VOLTS AC OR AC COUPLED HZ VOLTS DC OR DC COUPLED HZ DWELL OR DUTY CYCLE PUSHBUTTON See Table 3 RPM WITH OPTIONAL RPM 80 Q m 4 RESISTANCE OR CONTINUITY TEST TEMPERATURE OR DIODE TEST AMPS DC OR AC mtO1f eps Figure 1 Rotary Switch 78 Users Manual Input Jacks A 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 inpu
34. range Therefore ensure that the meter is in the desired range before you put the meter in MIN MAX To do so first take a measurement Notice the range shown at the upper right of the bar graph 3 Ifthe meter is not in the desired range press C 2 momentarily to step up a range Each press steps up a range After the highest range the meter wraps to the lowest range 36 4 When the meter is in the desired range press for 1 second to select MIN MAX MAX lights on the LCD indicating MIN MAX is se lected and the maximum reading is displayed The beeper sounds when a new minimum or maximum value is recorded After MIN MAX is selected press C to step through the minimum MIN lights present MIN and MAX blink and maximum lights readings To exit MIN MAX and erase the stored readings press C for 1 second or turn the rotary switch Because the standby sleep mode is disabled if you do not exit MIN MAX the meter records minimum and maximum values until the battery goes dead Figure 16 shows how to use MIN MAX to check an oxygen lambda sensor How to Store Minimum and Maximum Measurements Turn off engine and insert test leads in the jacks shown Set rotary switch to volts dc The meter defaults to the 40 V range Press the pushbutton 5 times to step to the 4 V range Connect the test leads to the sensor as shown Start the engine If the sensor p Pe is unheated fast idle the car for a
35. s gt 200 ms in duration 52 digits in 400 Nomina Response time 5 to 100 of Range 100 ms to Specifications Function AC Volts 45 Hz to 1 kHz DC Volts Resistance Continuity Diode Test AC Current 45 Hz to 1 kHz DC Current Range 4 000 V 40 00 V 300 0 V 300 V 400 0 mV 4000 mV 4 000 V 40 00 V 300 0 V 300 V 400 0 Q 4 000 kQ 40 00 400 0 kQ 4 000 MQ 40 00 MQ 400 0 Q 2 500 V 10 00 A 4 000 A 10 00 A Resolution 0 001 V 0 01 V 0 1V 1V 0 1 mV 1mV 0 001 V 0 01 V 0 1V 1V 010 0 001 00 01 000 1 0 001 0 01 010 0 001 V 0 01 0 001 0 01 Input Impedance 10 MQ nominal lt 150 pF gt Accuracy 2 5 2 r on lt 30 Q for of 1 ms of longer 2 typical 2 5 2 1 0 5 1 0 2 40 A continuous 20 A Overload for 30 seconds maximum Burden Voltage Typical N A N A N A Open circuit voltage lt 1 5 V Open circuit voltage lt 3 3 V 0 03 V A 0 03 V A 0 03 V A 47 78 Users Manual Function 2 Hz V RPM m 48 Overload 300 V 300 V 300 V 30 V 300 V rms 300 V rms 30 V rms T 10 V Hz max Input Impedance gt 10 MQ 150 pF gt 10 MQ 150 pF gt 10 MQ 150 pF 2 MQ 50 pF Open Circuit Test Voltage 1 3 V dc 3 3 V dc
36. splay 78 Users Manual C 2 Pushbutton The pushbutton selects different operations depending on the position of the rotary switch AND how long you hold it down See Table 3 e Press for less than 1 second a momentary press to perform stepping or toggling operations e g stepping through ranges or toggling between C and F The meter acknowledges a momentary press by a click e Press for more than 1 but less than 2 seconds to enter the MIN MAX mode In MIN MAX the lowest and highest readings are stored See How to Use MIN The meter acknowledges a 1 second press by a click and a beep The display briefly shows MAX MIN and PIPA e Press for 2 seconds or longer to toggle be tween the primary and alternate function of a switch setting Primary functions are labeled white secon dary functions yellow 10 The meter acknowledges a 2 second press by a click a single beep and a double beep The display briefly shows Pushbutton operations are summarized in Table 3 Standby Sleep Mode If the meter is ON but the rotary switch or the pushbutton is not operated for 30 minutes the meter enters the standby mode and the display goes blank This extends battery life To resume operation turn the rotary switch or press C 2 Standby is disabled in the MIN MAX mode Getting Acquainted with the Meter Table 3 Pushbutton Operations I
37. su M 4 Interpreting the Bar Graph nennen nnne nennen nnne nnne nennen 5 Measuring No Load Voltage of 42 4 0 6 Testing Diodes in Alternator Rectifier Bridge 7 Isolating Circuit Causing Current Drain a 8 Testing Continuity in a Switch 9 Measuring Resistance to Check Coolant Temperature Sensor 10 Measuring RPM with the Optional Inductive 11 Checking Barometric Pressure Manifold Absolute Pressure 12 Using AC Coupled Frequency on a Crankshaft Position 13 Measuring Dwell on a Conventional 14 Measuring Duty Cycle on a Feedback 15 Measuring the Temperature of Coolant Temperature 16 Using MIN MAX to Check an Oxygen 2 0 4000 17 Using Bar Graph to Observe Sweep of Throttle Position Sensor TPS 78 Users Manual 18 19 20 21 Holster and 6
38. t jacks Figure 2 that are pro tected against overloads to the limits shown on the front and back of the meter Thermocouple Adapter A 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 G or F to 260 C 500 in teflon compatible environ ments A 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 RPM VOLTS OHMS DIODE TEST DWELL DUTY CONTINUITY A AND HZ wa Cet Ae D AMPS 10 A CONTINUOUS 20 A FOR 30 SEC COMMON RETURN JACK FOR VOLTS OR COMMON FOR RPM OHMS DIODE TEST TEMPERATURE DWELL DUTY CYCLE CONTINUITY AND HZ mt02f eps Figure 2 Input Jacks 78 Users Manual Display Readings are shown on a liquid crystal display LCD Symbols
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