STEVE ZACK 1

ECGELECTRON COMBUSTION GRAPH

FOLLOW THE BOUNCING ELECTRON

2

UNDERSTANDING THE PATTERN

LAB SCOPE

• PULSE WIDTH (P.W.) IS THE TIME THE CIRCUIT IS ON, COMPLETING ITS PATH TO GROUND

• MEASURED IN MILLISECONDS (m.s.)

• MEASURED FROM THE BEGINNING OF ON TO THE END OF ON

4

LAB SCOPE

OFF OFF

ON

PULSEWIDTH

PULSE WIDTH

LAB SCOPE

• FREQUENCY (Hz) IS THE NUMBER OF TIMES SOMETHING OCCURS WITH IN ONE SECOND

• MEASURED IN HERTZ (Hz)

6

LAB SCOPE

0 10 20 30 40 50 60 70 80 90 1 10 20 30 40 50 60 70 80 90 2MILLISECONDS

FREQUENCY

2 OCCURENCES EVERY SECOND EQUALS 2 Hz

7

HOOKING UP THE SCOPE

LAB SCOPE

• TO TEST A SENSOR, BACK PROBE THE SENSOR SIGNAL RETURN WIRE

• TO TEST AN ACTUATOR, BACK PROBE THE COMPUTER CONTROLLED GROUND

9

SENSOR - BACK PROBE SIGNAL RETURN

HALL EFFECT SWITCH

10

ACTUATOR (INJECTOR) - BACK PROBE COMPUTER CONTROLLED GROUND

INJECTOR

LAB SCOPE

• NOISE IN A WAVE FORM CAN BE CAUSED BY AN OUTSIDE SOURCE OR MAGNETIC FIELD

• ALWAYS USE THE SCOPES CHASSIS GROUND AND HOOK IT TO THE ENGINE BLOCK

• KEEP THE SCOPE LEADS AWAY FROM ELECTRICAL DEVISES

12

GROUND

CHASSIS GROUND

NOICE

13

PATTERNINTERPRETATION

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SENSOR SIGNAL RETURN - HI

PICK UP COIL

VSS, WSS, DISTRIBUTER

SENSOR SIGNAL RETURN - LO

15

GOOD PATTERN

BAD PATTERN

BAD PATTERN

WEAK PICKUP COIL

MISALIGNED POLE PIECE

16

SENSOR SIGNAL RETURN

TPS

CTS

17

GOOD PATTERN

BAD PATTERN

BAD PATTERN

BAD PATTERN

OPEN IN SENSOR RESISTOR

LOW RESISTANCE IN SENSOR

HIGH RESISTANCE IN SENSOR

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SENSOR SIGNAL RETURN

HALL EFFECT SWITCH

DISTRIBUTER

CRANK SENSOR

MAF

19

GOOD PATTERN

GOOD PATTERN

BAD PATTERN

BAD PATTERN

SIGNATURE PROFILE PIP #1 TDC

AS LOAD OR SPEED INCREASE, Hz INCREASE

TIME CHANGE WITHOUT LOAD CHANGE

OFF SIGNAL CRASH

20

BAD PATTERN

BAD PATTERN

BAD PATTERN

ON SIGNAL NOT STABLE

LOOSE GROUND WIRE

LOOSE VOLTAGE WIRE

21

COMPUTER CONTROLLED GROUND

INJECTOR

SOLENOID

22

GOOD PATTERN

GOOD PATTERN

GOOD PATTERN

BAD PATTERN

NARROW P.W. - LEAN WIDE P.W. - RICH

LOW FREQUENCY HIGH FREQUENCY LEAN RICH

LOOSE VOLTAGE WIRE

23

BAD PATTERN

BAD PATTERN

LOOSE GROUND WIRE

WEAK SOLENOID COIL

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ALTERNATOR OUTPUT

ALTERNATOR

CHARGING SYSTEM - ALTERNATOR DIODE

TO BATTERY +

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GOOD PATTERN

BAD PATTERN

BAD PATTERN

BAD PATTERN

BAD PATTERN

BOUNCING BRUSH

POSITIVE DIODE SPIKE

NEGATIVE DIODE SPIKE

OPEN DIODE

26

BAD PATTERN

BAD PATTERN

BAD PATTERN

FLAT DIODE

POOR BRUSH CONTACT

EXCESS AC VOLTAGE

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O2 SIGNAL RETURN

HO2S

HEGO

EGO

O2 SENSOR

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GOOD O2 PATTERN

SECONDARY OR LEAN MISFIRE

LESS THAN 100ms

O2 SENSOR MUST SWITCH RICH TO LEAN AND LEAN TO RICH IN LESS THAN 100ms FOR CATALYST TO OPERATE

TEST AT 2000 RPM ENGINE AT OPERATING TEMPERATURE

O2 SENSOR TEST

30

SINGLE SPARK PLUG WIRE TEST - POLARITY MAY NEED TO BE REVERSED TO INVERT PATTERN

31

PERCEPTION SCOPE - SECONDARY IGNITION TEST

• ENGINE HOT

• 1000 RPM

• SPECIFICATIONS– BURN kV = 1.1 kV TO 2.1 kV– BURN TIME = 1.0 ms TO 1.8 ms– FIRING kV =

• 7.5 kV TO 12 kV DISTRIBUTER • 5 kV TO 12 kV DIS

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GOOD - PATTERNTURBULENCE, INTAKE VALVE, CARBON ON INTAKE VALVE, CARBON ON PLUG

FOULED PLUG - CARBON LOW COMPRESSION

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EXHAUST VALVE INTAKE VALVE, LEAN MISFIRE

FOULED PLUG - OIL, FUEL, CARBON

FUEL FOWLING, RICH CONDITION - CONDENSING AT CYLINDER WALLS

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TROUBLE TREE

CHART

35

TROUBLE TREE CHART

STEP A:

TO TEST ALL CIRCUITS AND THE SENSOR.

BACK PROBE SIGNAL RETURN AT THE PCM.

NO PROBLEM - CIRCUIT OK

YES PROBLEM - GO TO STEP B

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STEP A

PCM

37

TROUBLE TREE CHARTSTEP B:

TO TEST SENSOR, 5 VOLT AND GROUND CIRCUIT.

BACK PROBE SIGNAL RETURN AT THE SENSOR.

NO PROBLEM - REPAIR SIGNAL RETURN CIRCUIT

YES PROBLEM -ANALOG SENSOR - GO TO STEP C

DIGITAL SENSOR - GO TO STEP D

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STEP B SENSOR

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TROUBLE TREE CHART

STEP C:

ANALOG SENSOR

TO TEST 5 VOLT AND GROUND CIRCUIT.

BACK PROBE 5 VOLT AND GROUND CIRCUIT.

NO PROBLEM - REPLACE SENSOR

YES PROBLEM - REPAIR 5 VOLT OR GROUND CIRCUIT

40

STEP C

5 VOLT

REFERENCESTEP C

SENSOR GROUND

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TROUBLE TREE CHARTSTEP D:

DIGITAL SENSOR

THREE AREAS

A - VOLTAGE SUPPLY CIRCUIT (PROBLEMS - REPAIR CIRCUIT)

B - SENSOR(PROBLEMS - REPLACE SENSOR)

C - GROUND CIRCUIT(PROBLEMS - REPAIR CIRCUIT)

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SUMMARYTROUBLE SHOOTING PROCEDURE

0 VOLT

5 VOLT

“A”

“B”

“C”