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Ford EEC IV. Operation and Testing. Overview . A/F Mixture Ignition Timing Idle Speed Thermactor Airflow Canister Purge EGR Flow TCC AC Fan WOT Cut Off Inlet Air Temp Fuel Pump Relay Turbo Boost. ECT MAP/BARO TPS CKP/CMP O2S EGR Position ACT KS BOO AC Power Steering. PCM.
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Ford EEC IV Operation and Testing
Overview A/F Mixture Ignition Timing Idle Speed Thermactor Airflow Canister Purge EGR Flow TCC AC Fan WOT Cut Off Inlet Air Temp Fuel Pump Relay Turbo Boost ECT MAP/BARO TPS CKP/CMP O2S EGR Position ACT KS BOO AC Power Steering PCM
Operating Modes • Base Engine Strategy • MPG Lean Cruise • Modulator Strategy • Limited Operational Strategy • Adaptive Strategy
Base Engine Strategy • Used to control warm engine running • Open Loop starts at 130o • Warm up mode sub modes • Cranking • Closed-throttle • Part throttle (closed loop) • Wide-open throttle (WOT) • PCM controls actuators for good driveability
MPG Lean Cruise • Some engines beginning 1988 • Certain criteria are met • Goes out of closed-loop fuel control • Very lean for economy at cruise
Modulator Strategy • Conditions that require significant change from Base Engine Strategy • Cold engine • Overheated engine • High altitude
Limited Operational Strategy • Component Failure • Protect other components • Converter • Substitute values from another sensor • MAP TPS • ECT IAT • EGR Disable EGR
Adaptive Strategy • Started in 1985 • PCM has base map • Monitors operation and modifies base map • Compensates for wear etc. • Dirty Injectors • Are in response to O2S • Stored in KAM
Inputs A/F Mixture Ignition Timing Idle Speed Thermactor Airflow Canister Purge EGR Flow TCC AC Fan WOT Cut Off Inlet Air Temp Fuel Pump Relay Turbo Boost ECT MAP/BARO TPS CKP/CMP O2S EGR Position ACT KS BOO AC Power Steering PCM
Engine Coolant Temp • Thermistor • Voltage to PCM is 4.5 cold to .3 hot • Resistance 470K cold to 1k hot • Influences PCM’s calibrations for • A/F Raito • Idle Speed • Thermactor Air • Canister Purge • Choke Voltage, Temp compensated accel pump • Upshift light
Pressure Sensors • MAP, BARO • Pressure-sensitive capacitor • Convert to frequency out • 100 Hz no load Idle • 159 Hz atmospheric (WOT) • Voltage will go from 0 to 5 at the frequency above
Pressure Sensors • MAP used for BARO • PCM uses Key On before cranking and WOT for BARO calculations. • BARO used with Vane Airflow Sensors • Looks like MAP with collar
Throttle Position Sensor • Some adjustable, some not • Potentiometer • 3 wires, 5v reference, ground, signal • Two common problems • Bad spot, signal dropout • Bad ground • Full reference on signal • Biased high
Profile Ignition Pickup (PIP) • Hall Effect Switch • Engine speed and crank position • In distributor • One vane narrower for location
Profile Ignition Pickup (PIP) • On DIS sensor is on front of engine • One vane for each pair of companion cylinders • Most PIP signals go from .4v or less to battery voltage at 10o BTDC
Cylinder Identification (CID) • Used with Distributorless Ignition • PIP doesn't know which stroke • Driven at cam speed • Also usedfor SFI
4 Cylinder PIP CID • On DIS, 1 & 4 fire together • CID is on crank with PIP
Ignition Diagnostic Monitor • Used on TFI systems • Checks to see that spark occurred • Wire with 22k from Tach wire to PCM • Makes sure SPOUT command is carried out • Makes sure timing advance is working
Knock Sensor (KS) • Piezoelectric type • Vibration sends signal to PCM • PCM retards timing 1/2o per engine revolution
Intake Air Temp Sensor (IAT) • Was called Air Charge Temp (ACT) before OBDII • Thermistor • Voltages and resistance same as ECT • A/F and advance • Used on most Fords
EGR Position (EVP)Feedback (PFE) • EVP Linear Potentiometer • only monitors position • EVP Black and White physically interchangeable • PFE is like MAP but gives a voltage • Measures exhaust pressure under EGR valve • PFE measures flow used to • Fine tune EGR position • Fine tune A/F ratio • Modify ignition timing
Vane Air Flow (VAF) • Used with VAT and BP to calculate Speed Density
Mass Airflow MAF • Beginning in 1988 • Uses sample tube • Uses hot wire • Encased in Glass • 200o above ambient • A/F and Timing
Transmission Switches • PCM knows if in gear, park or neutral • Affects Idle air control strategy • For A/T because converter loads engine • Response to rapid throttle closing
Transmission Switches • AXOD uses 3 switches • Neutral Pressure NPS • Trans Hydraulic THS 3-2 • Trans Hydraulic THS 4-3 • AXOD Trans Temp TTS opens over 275oF • Will apply TCC if temps get high like uphill climb Can tell which gear except if it is in 1 or 2
Transmission Switches • Manual Trans • Neutral Gear Switch NGS • Clutch Engaged Switch CES • Wired in parallel so both must be open for PCM to know car is in gear.
Brake On/Off BOO • In stop lamp switch • A4LD has PCM controlled converter lockup • Used on most models today • Increases idle when in gear and brakes are on • May disengage AC on prolonged idle
Vehicle Speed Sensor (VSS) • Speedometer output • Mechanical or electric speedometer. • 8 cycles per revolution • 128000 signals per mile • Used for • TCC lockup • Coolant fan control • Identify deceleration
Other Inputs • Power Steering Pressure Switch PSPS • Opens between 400 and 600 PSI • Increases idle speed • AC Demand (ACD) • AC Clutch Cycling Switch (ACCS) • PCM watches to increase idle speed
Outputs A/F Mixture Ignition Timing Idle Speed Thermactor Airflow Canister Purge EGR Flow TCC AC Fan WOT Cut Off Inlet Air Temp Fuel Pump Relay Turbo Boost ECT MAP/BARO TPS CKP/CMP O2S EGR Position ACT KS BOO AC Power Steering PCM
Air / Fuel Mixture Control • Three types • Feedback Carburetors • Central Fuel Injection (TBI) • Electronic Fuel Injection (PFI) • Non Sequential • Group • Sequential
Feedback Carburetors • Motorcraft & Carter uses solenoid to bleed air into idle and main metering circuits
Holley Carburetors • Holley uses remote solenoid with similar idle control
Holley Carburetors • Uses vacuum diaphragm and valve for main metering control
Central Fuel Injection • Low Pressure System • Single injector • Low Pressure System • Two injectors • Alternates injectors • ECM grounds to turn on • Pulse Width Modulated
Port Fuel Injection • Non-sequential (EFI) • Group or bank-to-bank • Two Groups • Sequential (SEFI) • Injectors pulsed one at a time in firing order • Used throughout product line by early 1990s
Fuel Supply System • Fuel Pump • In tank • Trucks may have a lift and pressure pump • Most are around 39 psi • Pressure relief at 100 psi
Fuel Supply System • Pressure regulator • Manifold pressure modified • Low of 30 around psi (deceleration) • High of 39 psi (WOT) • Turbocharged may go as high as 50 psi • CFI does not use manifold pressure. • High pressure 38-40 psi • Low pressure 14.5 psi
Fuel Supply System • Fuel Pump Relay PCM Controlled • Turns on with key for 1-2 seconds or until PIP signal is present. • Inertia Switch is in series with pump
Thick Film Integrated (TFI-IV) • Thick film refers to the type of semi-conductor • Controls spark primary • Sends PIP to PCM • PCM modifies and sends back SPOUT • SPOUT tells TFI when to turn primary on and off. • In distributor or “Closed Bowl”