ECG ELECTRON COMBUSTION GRAPH FOLLOW THE BOUNCING ELECTRON STEVE ZACK STEVE ZACK

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

LAB SCOPE PULSE WIDTH ON PULSE WIDTH OFF OFF

LAB SCOPE FREQUENCY (Hz) IS THE NUMBER OF TIMES SOMETHING OCCURS WITH IN ONE SECOND MEASURED IN HERTZ (Hz)

LAB SCOPE FREQUENCY 2 OCCURENCES EVERY SECOND EQUALS 2 Hz 0 10 20 30 40 50 60 70 80 90 1 10 20 30 40 50 60 70 80 90 2 MILLISECONDS

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

SENSOR - BACK PROBE SIGNAL RETURN HALL EFFECT SWITCH

ACTUATOR (INJECTOR) - BACK PROBE COMPUTER CONTROLLED GROUND

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

GROUND CHASSIS GROUND NOICE

PATTERN INTERPRETATION

PICK UP COIL VSS, WSS, DISTRIBUTER SENSOR SIGNAL RETURN - HI SENSOR SIGNAL RETURN - LO

GOOD PATTERN BAD PATTERN WEAK PICKUP COIL MISALIGNED POLE PIECE

SENSOR SIGNAL RETURN TPS CTS

GOOD PATTERN BAD PATTERN OPEN IN SENSOR RESISTOR LOW RESISTANCE IN SENSOR HIGH RESISTANCE IN SENSOR

SENSOR SIGNAL RETURN HALL EFFECT SWITCH DISTRIBUTER CRANK SENSOR MAF

GOOD PATTERN BAD PATTERN SIGNATURE PROFILE PIP #1 TDC AS LOAD OR SPEED INCREASE, Hz INCREASE TIME CHANGE WITHOUT LOAD CHANGE OFF SIGNAL CRASH

BAD PATTERN ON SIGNAL NOT STABLE LOOSE GROUND WIRE LOOSE VOLTAGE WIRE

COMPUTER CONTROLLED GROUND INJECTOR SOLENOID

GOOD PATTERN BAD PATTERN NARROW P.W. - LEAN WIDE P.W. - RICH LOW FREQUENCY HIGH FREQUENCY LEAN RICH LOOSE VOLTAGE WIRE

BAD PATTERN LOOSE GROUND WIRE WEAK SOLENOID COIL

CHARGING SYSTEM - ALTERNATOR DIODE ALTERNATOR OUTPUT TO BATTERY + ALTERNATOR CHARGING SYSTEM - ALTERNATOR DIODE

GOOD PATTERN BAD PATTERN BOUNCING BRUSH POSITIVE DIODE SPIKE NEGATIVE DIODE SPIKE OPEN DIODE

BAD PATTERN FLAT DIODE POOR BRUSH CONTACT EXCESS AC VOLTAGE

O2 SIGNAL RETURN HO2S HEGO EGO O2 SENSOR

GOOD O2 PATTERN SECONDARY OR LEAN MISFIRE

TEST AT 2000 RPM ENGINE AT OPERATING TEMPERATURE O2 SENSOR TEST 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

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

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

TURBULENCE, INTAKE VALVE, CARBON ON INTAKE VALVE, CARBON ON PLUG GOOD - PATTERN FOULED PLUG - CARBON LOW COMPRESSION

EXHAUST VALVE INTAKE VALVE, LEAN MISFIRE FUEL FOWLING, RICH CONDITION - CONDENSING AT CYLINDER WALLS FOULED PLUG - OIL, FUEL, CARBON

TROUBLE TREE CHART

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

STEP A PCM

TROUBLE TREE CHART STEP 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

STEP B SENSOR

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

STEP C 5 VOLT REFERENCE STEP C SENSOR GROUND

TROUBLE TREE CHART STEP D: DIGITAL SENSOR THREE AREAS A - VOLTAGE SUPPLY CIRCUIT (PROBLEMS - REPAIR CIRCUIT) B - SENSOR (PROBLEMS - REPLACE SENSOR) C - GROUND CIRCUIT

SUMMARY TROUBLE SHOOTING PROCEDURE 5 VOLT “A” “C” 0 VOLT