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Nemisys Advanced Class

Nemisys Advanced Class. Fuel Trim. Spec 10 to 30 High IAC counts LTFT over +10 MAP normal .8 to 1.5 Idle Check ignition Dirty intake valves, Injectors, or Throttle plates Leaking EGR Check fuel pressure and volume. Spec 10 to 30 IAC Counts High over 40 LTFT over +10

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Nemisys Advanced Class

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  1. Nemisys Advanced Class

  2. Fuel Trim

  3. Spec 10 to 30 High IAC counts LTFT over +10 MAP normal .8 to 1.5 Idle Check ignition Dirty intake valves, Injectors, or Throttle plates Leaking EGR Check fuel pressure and volume Spec 10 to 30 IAC Counts High over 40 LTFT over +10 MAP sensor high or MAF sensor low <5 Sticking IAC Dirty intake valves, Injector, or Throttle plates Check fuel pressure and volume Low Manifold pressure or compression problems IAC motor stuck open IAC Counts High

  4. Fuel Control Test Clear Flood Equipped Vehicles A) DataStream • TPS • Injector Pulse Width B) KOEO C) WOT • TPS 4.3 To 4.7 Volts • Injector Pulse Width 0.0

  5. Scan Tool Fuel Control Test(Easy to get HO2S) • 1) Disconnect HO2S • 2) Datastream • HO2S • Injector Pulse Width • 3) Volt Meter At HO2S Signal Return Wire at O2 sensor • 4) KOER, Engine At Operating Temperature, 1000 Rpm • 5) Place One Finger On PCM HO2S Signal Return Wire to the PCM • 6) Place Another Finger At Battery Positive • Datastream HO2S - 1 Volt • Datastream Injector Pulse Width - Will Drop • Volt Meter HO2S - 0 Volt • 7) Place Finger At Battery Negative • Datastream HO2S - 0 Volt • Datastream Injector Pulse Width - Will Rise • Volt Meter HO2S - 1 Volt

  6. O2 Sensor Propane Test • Propane enrichment testing to check that the O2 sensors are working properly • Select, graph and zoom the O2 sensors • Propane enrichment increases the O2 output above .91 volts, preferred is closer to 1.0 volt. • Keep adding propane until RPM decreases, to get the maximum output • Remove the propane to see how fast the voltage decreases. It should decrease in a straight line

  7. Timing Advance Datastream Test • Datastream review of Timing Advance versus RPM • The timing advance should follow RPM, except when in Wide Open Throttle, when timing advance decrease slightly

  8. Timing Advance Datastream Test • Datastream review of Timing Advance versus TPS • TPS moves and Spark changes good reaction and timing curve

  9. Timing Advance Datastream Test • Datastream review of Timing Advance versus MAP • The spark advance must follow the MAP sensor load changes

  10. MAF Test • 1) KOER, Engine At Operating Temperature • 2) Scan Tool Datastream • MAF GPS • (Frequency May Be Substituted For GPS) • 3) Mark Points Of MAF GPS On Graph Paper • 1000 Rpm • 1250 Rpm • 1500 Rpm • 1750 Rpm • 2000 Rpm • 4) Connect Plot Points, Graph Line Should Rise Smooth

  11. Good MAF Graph GPS RPM 1000 1250 1500 1750 2000

  12. Bad MAF Graph - Out of Calibration GPS RPM 1000 1250 1500 1750 2000

  13. Bad MAF Graph - Air Leak GPS RPM 1000 1250 1500 1750 2000

  14. MAF Test • Select and graph RPM and MAF • Ford MAF sensor should reach a output of above 3.5 volts with a snap throttle

  15. GM MAF TEST • GM with a snap throttle should go above the 5.4 kHz for a good sensor output • Check MAF sensing wires or clean the wires, and check the duct work for leaks after the MAF sensor

  16. Vacuum Voltage Scan Data 0” 4.5-4.7 V 29-30” 3” 4.0-4.2 V 26-27” 6” 3.5-3.7 V 23-24” 9” 3.0-3.2 V 20-21” 12” 2.5-2.7 V 17-18” 15” 2.1-2.3 V 14-15” 18” 1.5-1.7 V 11-12” 21” .9-1.1 V 8-9” GM MAP Sensors

  17. Altitude Baro Pressure Voltage 0-1000’ 29-30” 4.5-4.8 V 1000 to 2000’ 28-29 4.3-4.5 V 2000 to 3000’ 27-28” 4.1-4.3 V 3000 to 4000’ 26-27” 3.9-4.1 V 4000 to 5000’ 25-26” 3.8-4.0 V GM/Chrysler BARO Readings

  18. Vacuum Voltage Scan Data 0” 4.5-4.8 V 29-30” 3” 4.0-4.2 V 26-27” 6” 3.5-3.7 V 23-24” 9” 3.0-3.2 V 20-21” 12” 2.5-2.7 V 17-18” 15” 2.1-2.3 V 14-15” 18” 1.5-1.7 V 11-12” 21” .9-1.10 V 8-9” Chrysler MAP

  19. Vacuum Frequency in HZ 0” 159 Hz 3” 150 Hz 6” 141 Hz 9” 132 Hz 12” 123 Hz 15” 114 Hz 18” 105 Hz 21” 96 Hz Ford MAP Sensors

  20. Altitude Vs. Frequency 0-1000’ 29-30” 159-163 Hz 1000-2000’ 28-29” 153-157 Hz 2000-3000’ 27-28” 150-153 Hz 3000-4000’ 26-27” 147-153 Hz 4000-5000’ 25-26” 144-150 Hz FORD BARO Readings

  21. MAP Sensor Test • 1) Scan Tool Datastream • Map Sensor Voltage • 2) KOEO • 3) Attach Vacuum Pump To Map Sensor Vacuum Port • 4) 0 Vacuum, 3.9 To 4.7 Volts • 5) 18 To 20 Inches Vacuum, .8 To 1.5 Volts

  22. Cranking Vacuum/Pressure • Cranking Vacuum can be tested using the MAP Sensor • The voltage or pressure should decrease in response to vacuum

  23. Reaction Testing • Testing the TPS against the MAP sensor shows the response of the sensors • They should follow each other. • This test will verify CAM to Crankshaft timing • This test will verify if the TPS sticks when closing

  24. GM Throttle Body Injection .55 to .75 volts=0% closed Cold / Warm GM Port Fuel Injection .29 to .58 volts=0% closed cold .4 to .58 volts closed=0% warm idle running Ford .8 to 1 volt Wide Open Throttle 4.3 minimum Chrysler .6 to 1.1 volts Wide Open Throttle 2.6 volts above stored minimum TPS TPS Quick Specs

  25. TPS Sweep Test • 1) KOEO • 2) Scan Tool Datastream • TPS • 3) Open And Close TPS, Smooth Linear Rise

  26. Two Wire Sensor Testing • Check for Voltage supply • Voltage supply must be above 4.6 volts • Scan tool should read cold –40°F • Short the pins in the connector together • Reading on DVOM should be less than .050 mv • Scan tool reading should be above 260°F

  27. Three Wire Testing • Check for Voltage Reference • Range 4.9 to 5.1 volts • Check for proper ground • Red lead at sensor ground and black lead at battery ground, voltage should read under .050mv • Short VREF pin and Signal pin together • Datastream should read the same as VREF • Short signal pin and ground pin together • Datastream should read zero

  28. Cylinder Misfire Testing • Engine at operating temperature • Vehicle at cruise speed • Monitor rear or post HO2S • Base line voltage .430mv to .470mv • Rear HO2S voltage high • Secondary Ignition miss fire • Rear HO2S voltage low • Lean Injector miss fire

  29. Catalyst Test 1 • 1) Engine at Operating Temperature • 2) All Basic Engine Functions Must Be in Good Working Order • 3) Raise Engine Rpm to 2000 and Hold Steady • 4) 3 Minutes Minimum • 5) Monitor HO2S Sensors Upstream and Downstream • 6) Upstream Should Be Swinging Rich to Lean • 7) Downstream Should Be Steady With Small Swing of 430 to 470 Mv

  30. Catalyst Efficiency MonitorPre-HO2S Post-HO2SUpstream HO2S Downstream HO2SS1 S2 800 mv 450 mv 200 mv 470 mv 450 mv 430 mv

  31. Catalyst Test 2 • To test for a plugged Catalytic Converter, graph MAP Voltage • With the engine running at 2000 RPM for 3 minutes note what MAP Voltage is, it should be around 1.2 to 1.6 Volts • Snap the throttle to wide open from 2000 RPM • MAP Voltage will rise from 2000 RPM at wide open throttle to approximately 3.8 to 4.2 Volts • When the engine returns to idle MAP Voltage should return to 1.2 to 1.6 Volts in less than 3 seconds • If it takes longer than 3 seconds the Catalytic Converter maybe plugged

  32. Charging Systems Test • 1) KOER • 2) At Idle verify Battery Volts • 3) At 2000 RPM verify Battery Volts • Turn all accessories on • Voltage should rise to 14 to 15 volts

  33. Cranking Voltage Test • Record the voltage • Put the engine in Clear Flood mode • Crank the engine for 15 seconds • Cranking Voltage should not go under 9.6 • Recovery Voltage should come close to the recorded voltage in less than 7 seconds

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