Engine Controls - System/component Tests — Acura Integra II (1989-1993)

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC TESTING article in the ENGINE PERFORMANCE Section. Since many computer-controlled and monitored components set a trouble code if they malfunction, also perform procedures in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

Scheme 11

Scheme 11: INTRODUCTION

ATMOSPHERIC PRESSURE (PA) SENSOR

Sensor is located inside ECU. Check for code stored in ECU memory. See G - TESTS W/ CODES article in the ENGINE PERFORMANCE Section.

COOLANT TEMPERATURE (TW) SENSOR

Disconnect 2-wire connector (Red/White and Green/White wires) from sensor. Ensure resistance is as specified in COOLANT TEMPERATURE (TW) SENSOR RESISTANCE table.

Temperature - °F (°C)	(1) Resistance (Ohms)
-4 (-20)	15,000-18,000
68 (20)	1000-4000
176 (80)	200-400
(1) Measure resistance across sensor terminals.

(1)	Measure resistance across sensor terminals.

COOLANT TEMPERATURE (TW) SENSOR RESISTANCE

Scheme 12

Scheme 12: CRANK/CYL/TDC

To test sensor and wiring connections, turn ignition off. Probe appropriate ECU harness terminals to check for resistance of each sensor. See «ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS»(/acura/integra/ii-1989-1993/remont/testing-diagnostics/#engine-controls-systemcomponent-tests) table. If resistance is not correct, go to step 3). ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS Application ECU Terminals (1) Resistance (Ohms) CRANK B10 & B12 350-700 CYL C1 & C2 350-700 TDC C3 & C4 350-700 (1) Terminal identifications are imprinted on ECU connector.
If resistance is okay, check for continuity to ground on each terminal. If continuity is present, disconnect sensor connector, and recheck appropriate ECU terminal for continuity to ground. If continuity still exists, repair short to ground in harness. If continuity does not exist, replace sensor assembly.
Disconnect sensor connector at sensor. (Scheme 12) Check for sensor resistance. See «ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS»(/acura/integra/ii-1989-1993/remont/testing-diagnostics/#engine-controls-systemcomponent-tests) table. If sensor resistance is okay, repair open, short or corrosion in sensor harness between ECU and sensor. If sensor resistance is not okay, replace sensor assembly. NOTE: The following tests can only be performed with PGM-FI Test Harness (07999-PD60000A ). Terminals on PGM-FI test harness connectors match terminals on ECU and ECU connectors. This allows the technician to test continuity of specified wires and resistance of devices when the ECU is disconnected. When ECU is connected to PGM-FI test harness, sensor input values can be monitored (at the test connector terminals) while engine is in operation. To identify ECU terminals (Scheme 11)

EGR VALVE LIFT SENSOR (AUTOMATIC TRANSMISSION)

Measure voltage between Yellow/White (positive) and Green (negative) terminals by backprobing EGR valve lift sensor 4-wire connector. Voltage should be about 5 volts. If 5 volts not present, repair open in Yellow/White or Green wire between ECU and EGR valve. If voltage is okay, replace EGR lift sensor or repair short in Red/Green wire between ECU terminal C8 and EGR lift sensor.
Measure voltage between Red/Green wire (positive) and Green wire (negative) by backprobing EGR valve lift sensor 4-wire connector. If voltage is about 1.2 volts, slowly apply 8 in. Hg to EGR valve. Completely release and reapply vacuum several times. If maximum voltage in not about 4 volts, replace EGR valve and lift sensor.

INTAKE AIR TEMPERATURE (TA) SENSOR

Disconnect TA sensor 2-wire connector on throttle body. Check resistance. See INTAKE AIR TEMPERATURE (TA) SENSOR RESISTANCE table. Replace TA sensor if resistance is not correct.

Temperature - °F (°C)	(1) Resistance (Ohms)
-4 (-20)	15,000-18,000
68 (20)	1000-4000
176 (80)	200-400
(1) Measure resistance across sensor terminals.

(1)	Measure resistance across sensor terminals.

INTAKE AIR TEMPERATURE (TA) SENSOR RESISTANCE

MAP SENSOR

Disconnect vacuum hose from MAP sensor. Connect a hand-held vacuum pump to MAP sensor. MAP sensor is located on right center of firewall . Apply vacuum to MAP sensor. See MAP SENSOR VOLTAGE table. Backprobe ECU connector, and measure voltage between ECU terminal C11 (positive) and ground. Voltage reading should be as specified in MAP SENSOR VOLTAGE table. Replace MAP sensor if vacuum is not held or voltage is not as specified.

Vacuum Applied - In. Hg	Volts
0	2.8-3.0
5	2.3-2.5
10	1.8-2.0
15	1.3-1.5
20	.8-1.0
25	.3-.5

MAP SENSOR VOLTAGE

OXYGEN (O2) SENSOR

Disconnect O2 sensor wire(s). Start and warm engine to normal operating temperature. Measure voltage between O2 sensor connector and ground. Voltage should be greater than .6 volt at 5000 RPM and less than .4 volt when throttle is released quickly. If voltage is not as specified, replace O2 sensor.

Note. The following tests can only be performed with PGM-FI Test Harness (07999-PD60000A ). Terminals on PGM-FI test harness connectors match terminals on ECU and ECU connectors. This allows the technician to test continuity of specified wires and resistance of devices when the ECU is disconnected. When ECU is connected to PGM-FI test harness, sensor input values can be monitored (at the test connector terminals) while engine is in operation. To identify ECU terminals (Scheme 11)

THROTTLE ANGLE SENSOR

Disconnect 3-pin connector from throttle angle sensor on intake throttle body. Turn ignition on, and measure voltage between Yellow/White (positive) and Green (negative) wire terminals.
If voltage is not about 5 volts, measure voltage between Yellow/White (positive) terminal and ground. If voltage is about 5 volts, repair open in Green wire between ECU terminal C12 and throttle angle sensor.
If voltage is about 5 volts, turn ignition off. Reconnect 3-pin connector at throttle angle sensor. Connect PGM-FI test harness connector between ECU and ECU wire harness. Using a hand-held vacuum pump, apply vacuum to dashpot diaphragm to hold diaphragm in retract position.
Turn ignition on. Measure voltage between PGM-FI test harness connector terminals C7 (positive) and C12 (negative). Voltage should be about .3 volt with throttle valve at full-closed position and 4.5 volts with throttle valve at full-open position. As throttle opens, voltage should change smoothly from .3 volt to 4.5 volts.
If voltage is not as specified, check for short or open in Red/Blue wire between ECU terminal C7 and throttle angle sensor. Repair as necessary. If wire is okay, replace throttle angle sensor.

VEHICLE SPEED SENSOR

Connect PGM-FI test harness between ECU and ECU connectors. Raise vehicle front, and support with safety stands. Connect voltmeter between PGM-FI test harness terminals B16 (positive) and A18 (negative).
Turn ignition on. Slowly rotate left front wheel. Voltage should pulsate between zero and 5 volts. If voltage pulsates as specified, go to step 3). If voltage does not pulsate as specified, check for open or short in Yellow/Red wire between ECU terminal B16 and speed sensor. If wire is okay, replace faulty speed sensor or ECU.
Substitute a known good ECU, and retest. If problem goes away, replace ECU.

FUEL PUMP RELAY

Note. Fuel pump relay is also know as PGM-FI relay.

Scheme 13

Scheme 13: FUEL PUMP RELAY

Remove fuel pump relay located near underdash fuse box. Connect battery voltage to terminal No. 4, and ground terminal No. 8 of relay. (Scheme 13)
Check continuity between relay terminals No. 5 and 7. If continuity is present, go to next step. If continuity is not present, replace relay.
Connect battery positive to relay terminal No. 5, and ground terminal No. 2. Check continuity between relay terminals No. 1 and 3. If continuity exists, go to next step. If continuity does not exist, replace relay.
Connect battery positive to main relay terminal No. 3 and battery negative to terminal No. 8. Check continuity between relay terminals No. 5 and 7. If continuity exists, relay is okay. If continuity does not exist, replace relay.

EGR CONTROL SOLENOID VALVE

See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS

FUEL PRESSURE REGULATOR CUT-OFF SOLENOID VALVE

See FUEL DELIVERY under FUEL SYSTEM

IDLE-UP SOLENOID (AUTOMATIC TRANSMISSION)

See IDLE CONTROL SYSTEM

PURGE CUT-OFF SOLENOID VALVE

See EVAPORATIVE EMISSION CONTROLS under EMISSION SYSTEMS & SUB-SYSTEMS

FUEL DELIVERY SYSTEM

Note. For fuel system pressure testing, see appropriate test under FUEL SYSTEM in BASIC TESTING article in the ENGINE PERFORMANCE Section.

FUEL INJECTOR

Disconnect electrical connector from fuel injector. Measure resistance between fuel injector terminals. Resistance should be 1.5-2.5 ohms.

FUEL PRESSURE REGULATOR

See FUEL SYSTEM in BASIC TESTING article in the ENGINE PERFORMANCE Section.

Start engine, and warm to normal operating temperature. Disconnect vacuum hose No. 1 from cut-off solenoid valve, and connect a vacuum gauge to hose. If vacuum is present, go to step 4).
If manifold vacuum is not present, disconnect 4-wire connector from cut-off solenoid valve. If manifold vacuum is now present, go to next step. If manifold vacuum is still not present, check vacuum hoses No. 1 and No. 20. If hoses are okay, replace cut-off solenoid valve.
If manifold vacuum is present, check for short to ground in Green/Yellow wire between ECU terminal A10 and cut-off solenoid valve connector. If wire is okay, substitute a known good ECU, and retest. If problem is no longer present, replace original ECU.
Disconnect 4-wire connector from cut-off solenoid valve. Connect battery positive to terminal "C" (Black/Yellow wire) of cut-off solenoid valve side of connector. Connect battery negative to terminal "D" (Green/Yellow wire) of cut-off solenoid valve side of connector. Start engine, and allow it to idle. If manifold vacuum is present, replace cut-off solenoid valve.
If manifold vacuum is not present, measure voltage between Black/Yellow (positive) wire and ground. If battery voltage is not present, repair open in Black/Yellow wire between fuse No. 24 and 4-wire connector. Reconnect 4-wire connector to cut-off solenoid valve.
Connect PGM-FI test harness between ECU and connector. Start engine, and jump terminal A10 to ground. If manifold vacuum is not present, cut-off solenoid valve is okay. If vacuum is present, repair open in Green/Yellow wire between ECU and 4-wire connector.

FUEL PUMP

See FUEL SYSTEM in BASIC TESTING article in the ENGINE PERFORMANCE Section.

See RELAYS under RELAYS & SOLENOIDS

INJECTOR RESISTOR

Disconnect injector resistor connector. Check resistance between each injector resistor terminal and Yellow/Black wire power terminal. Resistance should be 5-7 ohms. If resistance is not correct, replace injector resistor.

IDLE CONTROL SYSTEM

AIR CONDITIONING SIGNAL

Connect PGM-FI test harness between ECU and ECU connectors. Disconnect connector "B" from main harness only; DO NOT disconnect from ECU. Turn ignition on.
Measure voltage between ECU terminals B8 (positive) and A18 (negative). If voltage is not about 5 volts, substitute a known good ECU, and recheck voltage.
If voltage is about 5 volts, reconnect connector "B" to main wiring harness. Touch terminals B3 to A18 together and check for clicking of A/C clutch.
If A/C clutch clicks, go to next step. If A/C clutch does not click, jumper Yellow wire of A/C clutch connector to ground. If A/C clutch clicks, repair open in Yellow wire. If A/C clutch still does not click, repair A/C clutch circuit.
Start engine, and turn blower on. Turn A/C switch on. If A/C operates, A/C signal is okay. If A/C does not operate, measure voltage between terminals B8 (positive) and A18 (negative).
If voltage is more than 1 volt, repair open in Blue/Red wire between B8 and A/C switch. If voltage is less than 1 volt, substitute a known good ECU, and recheck voltage.

ALTERNATOR FR SIGNAL

Connect PGM-FI test harness between ECU and ECU connectors. Disconnect connector "B" from main wire harness only; DO NOT disconnect from ECU. Turn ignition on. Check voltage between terminals B14 (positive) and A18 (negative). If voltage is NOT about 5 volts, substitute a good known ECU, and recheck.
If voltage is about 5 volts, turn ignition off. Reconnect connector "B" to main harness. Start engine, and warm it to operating temperature. Check voltage between ECU terminals B14 (positive) and A18 (negative). If voltage does not decrease, go to step 4).
If voltage decreases when headlights or rear defogger are turned on, alternator FR signal is okay. Turn ignition off. Remove alternator sensor fuse for 10 seconds to reset ECU.
Disconnect connector "B" from ECU only. Disconnect negative battery cable from battery. Check for continuity between PGM-FI test harness terminal B14 and ground. If continuity is present, disconnect Green connector from alternator.
Check again for continuity between PGM-FI test harness terminal B14 and ground. If continuity is not present, check alternator for possible failure. If continuity is present, repair Red/White wire between alternator and terminal B14 on ECU. NOTE: The following tests can only be performed with PGM-FI Test Harness (07999-PD60000A ). Terminals on PGM-FI test harness connectors match terminals on ECU and ECU connectors. This allows the technician to test continuity of specified wires and resistance of devices when the ECU is disconnected. When ECU is connected to PGM-FI test harness, sensor input values can be monitored (at the test connector terminals) while engine is in operation. To identify ECU terminals (Scheme 11) ECU connectors are identified as "A", "B" and "C" on harness.

AUTOMATIC TRANSMISSION SHIFT POSITION SIGNAL

While watching shift indicator, shift transmission gear to each position. If shift indicator lights up correctly for all positions, turn ignition off. Connect PGM-FI test harness between ECU and ECU connectors. Disconnect connector "B" from main harness only; DO NOT disconnect from ECU. Turn ignition on. Measure voltage between ECU terminals B7 (positive) and A18 (negative). If voltage is not around 10 volts, substitute a known good ECU, and recheck voltage.
If voltage is about 10 volts, reconnect connector "B" to main wiring harness. Place transmission in Neutral. Measure voltage between terminals B7 (positive) and A18 (negative). If voltage is more than 1 volt, repair open in Light Green wire between ECU B7 and connector.
If voltage is less than 1 volt, place transmission in Park, and measure voltage between terminals B7 (positive) and A18 (negative). If voltage is more than one volt, replace shift position signal.
If voltage is not more than one volt, place transmission in Drive, and measure voltage between terminals B7 (positive) and A18 (negative). If voltage is not about 10 volts, repair short in Light Green wire between ECU terminal B7 and combination meter. If voltage is about 10 volts, shift position signal is okay.

BRAKE SWITCH SIGNAL

Connect ECU tester to ECU main harness; DO NOT connect tester to ECU. Check voltage between harness terminals C10 (positive) and A18 (negative).
Depress brake pedal. If battery voltage is present, switch is okay. If battery voltage is not present, repair open in Green/White wire and ECU terminal C10.

ELECTRONIC AIR CONTROL VALVE (EACV) SYSTEM

Idle speed is controlled by EACV and fast idle valve. EACV valve changes amount of air by-passing into intake manifold. EACV responds to changes received by ECU from various sensor and signal sources.

EACV

Turn engine off, and disconnect 2-wire connector on EACV. Measure resistance between both terminals on EACV. Replace EACV if resistance is not 8-15 ohms. Check both terminals for continuity to ground. If continuity is present, replace EACV.
If continuity is not present, turn ignition on. Measure voltage between Black/Yellow (positive) and Blue/Yellow (negative) terminals. If battery voltage is not present, go to step 4).
If battery voltage is present, disconnect connector "A" from ECU. Measure voltage between Black/Yellow and Blue/Yellow wires of EACV 2-wire connector. If battery voltage is not present, repair short in Blue/Yellow wire between ECU terminal A11 and EACV. If battery voltage is present, substitute a known good ECU, and recheck voltage.
Measure voltage between Black/Yellow wire of EACV and ground. If battery voltage is not present, repair open in Black/Yellow wire between EACV connector and fuse No. 24.
If battery voltage is present, connect PGM-FI test harness connector "A" to main wire harness only; DO NOT connect to ECU. Turn ignition on. Measure voltage between terminals A11 (positive) and A2 (negative). If battery voltage is not present, repair open in Blue/Yellow wire between ECU terminal A11 and EACV.
If battery voltage is present, connect and disconnect jumper wire between terminals A11 and A2. If EACV does not click, replace EACV. If EACV clicks, substitute a known good EACV, and recheck symptom.

FAST IDLE VALVE

Fast idle valve opens an air passage, which bypasses throttle plate. This allows more air for a fast idle speed. Coolant warms valve and closes air passage. Ensure fast idle valve is closed when engine is at operating temperature.

MANUAL TRANSMISSION NEUTRAL SWITCH

Connect PGM-FI test harness between ECU and ECU connectors. Turn ignition on. Place transmission in Neutral, and measure voltage between ECU terminal B7 (positive) and A18 (negative). If voltage is not present, go to step 3).
If voltage exists, disconnect manual transmission neutral switch 2-wire connector located on side of transmission. Connect Blue wire terminal to Black wire terminal. If voltage is not present, replace neutral switch. If voltage is present, repair open in Blue wire between ECU terminal B7 and neutral switch.
Shift transmission into gear. If about 10 volts is present, manual transmission neutral switch is okay. If battery voltage is not present, disconnect PGM-FI test harness connector "B" from main wire harness only; DO NOT disconnect from ECU. If 10 volts is not present, substitute a known good ECU and recheck.
If about 10 volts is present, reconnect connector "B", and disconnect 2-wire connector on manual transmission neutral switch. If battery voltage is present, replace switch. If battery voltage is not present, repair short in Blue wire between ECU and manual transmission neutral switch.

POWER STEERING (P/S) OIL PRESSURE SIGNAL

Connect PGM-FI test harness between ECU and ECU connectors. Start engine. Measure voltage between ECU terminals B19 (positive) and A18 (negative). If voltage is less than one volt, go to step 3).
If voltage is more than one volt, disconnect 2-wire connector on P/S oil pressure switch located on power steering pump. Jump Red and Black wire terminals. If less than one volt is present, replace P/S pressure switch. If more than one volt is present, repair open in Red wire (between ECU terminal B19 and P/S oil pressure switch) or Black wire and ground connection.
Start engine, and turn steering wheel slowly. Measure voltage between ECU terminals B19 (positive) and A18 (negative) while wheel is being turned. If battery voltage exists, P/S oil pressure signal is okay.
If battery voltage is not present, turn ignition off. Disconnect PGM-FI test harness connector "B" from main wire harness only; DO NOT disconnect from ECU. Turn ignition on. If battery voltage is still not present, try a known good ECU. If problem goes away, replace ECU.
If battery voltage exists, reconnect connector "B" to main wiring harness. Disconnect P/S oil pressure switch 2-wire connector, and check Red wire for battery voltage. If voltage is present, replace P/S oil pressure switch. If voltage is not present, repair short in Red wire between ECU terminal B19 and P/S oil pressure switch.

STARTER SIGNAL

Connect PGM-FI test harness between ECU and ECU connectors. Check voltage on PGM-FI test harness terminals B13 (positive) and A18 (negative) with ignition switch in ON position. If battery voltage is present, starter signal is okay. If voltage is not present, inspect fuse No. 18. If fuse is okay, repair open in Black/White wire between ECU and fuse No. 18.

Warm engine until cooling fan comes on. Disconnect wire harness connector to idle-up solenoid valve. Start engine. Using a jumper wire, connect 12 volts to Black/Yellow (positive) wire terminal and ground to Blue/Red (negative) wire terminal of idle-up solenoid.
Vacuum signal should be present at idle-up valve vacuum hose. If vacuum signal is not present, check vacuum hose and hose routing. If vacuum hose and hose routing are okay, replace idle-up solenoid valve.

ADDITIONAL SENSORS & SWITCHES INPUTS

See ENGINE SENSORS & SWITCHES for testing procedures on following components.

Atmospheric Pressure (PA) Sensor
Coolant Temperature (TW) Sensor
Intake Air Temperature (TA) Sensor
Throttle Angle Sensor
TDC/CRANK/CYL Sensor

IGNITION SYSTEM

Note. For basic ignition checks, see BASIC TESTING article in the ENGINE PERFORMANCE Section.

Charcoal Canister

Connect vacuum gauge to canister purge air hose located at bottom of canister. Start engine, and increase engine speed to 3500 RPM. Vacuum gauge should read 0-4 in. Hg within one minute. If reading is not as specified, replace charcoal canister.

Coolant temperature must be less than 163°F (73°C). Remove vacuum hose from purge control diaphragm valve, and attach vacuum gauge to hose. Disconnect 6-wire solenoid valve connector. Start engine.
Apply 12-volts to Green (positive) and Black (negative) wires to energize solenoid valve. If vacuum is not present, replace purge cut-off solenoid valve.

Scheme 14

Scheme 14: 2-Way Valve

Remove fuel filler cap. (Scheme 14) Remove vapor hose from fuel tank side of 2-way valve, and install "T" fitting. Connect vacuum gauge to "T" fitting and vacuum pump to hose end.
Slowly apply vacuum while watching vacuum gauge. Vacuum reading should stabilize momentarily between.2-.6 in. Hg. If vacuum does not stabilize (valve opens) in specified range, replace 2-way valve, and retest.
Move vacuum hose from vacuum to pressure fitting side of vacuum pump. Slowly pressurize vapor line while watching gauge. If pressure stabilizes between.4-1.4 in. Hg, valve is okay. If pressure does not stabilize in specified range, replace 2-way valve, and retest.

Constant Vacuum Control (CVC)

Start engine. Ensure manifold vacuum is present at CVC valve located inside control box on firewall. Disconnect CVC vacuum hose at EGR cut-off solenoid. Connect vacuum gauge. If vacuum reading is not about 8 in. Hg, replace CVC valve.

Scheme 15

Scheme 15: EGR Control Solenoid Valve

Disconnect vacuum hose at EGR valve. (Scheme 15) Connect vacuum gauge to hose. Warm engine until cooling fan comes on. Increase engine speed to about 3000 RPM. Check vacuum gauge. If vacuum is present, solenoid is okay.
If vacuum is not present, disconnect connector from EGR control solenoid valve (at control box). Turn ignition on. Using voltmeter, check for voltage at EGR control solenoid connector. Connect voltmeter negative lead to ground, and backprobe connector's Black/Yellow wire terminal. If voltage is not present, check for blown fuse or open or short in EGR control solenoid power supply wire (Black/Yellow).
If voltage is present, increase engine speed to about 3000 RPM. Check voltage across solenoid terminals. If voltage exists but vacuum is not present, check for restricted hose or replace defective solenoid.
If voltage is not present, check for open in ground wire to solenoid. See appropriate «WIRING DIAGRAMS»(/acura/integra/ii-1989-1993/remont/wiring-diagrams-engine-performance/#wiring-diagrams) article in the ENGINE PERFORMANCE Section. If ground wire is okay, substitute a known good ECU, and retest. If problem goes away, replace original ECU.

EGR Valve

Warm engine to normal operating temperature. Disconnect vacuum hose from EGR valve. (Scheme 15) Connect vacuum pump to EGR valve. With engine at idle, apply vacuum to EGR valve. EGR valve should hold vacuum and engine should die.
If engine does not die and/or vacuum is not held, replace EGR valve. If vacuum is held but engine did not die, remove EGR valve, and check for plugged valve or passages. Clean or replace EGR valve as necessary.

EGR Valve Lift Sensor

See ENGINE SENSORS & SWITCHES

POSITIVE CRANKCASE VENTILATION (PCV)

Ensure crankcase ventilation hoses and connections are not clogged and no leaks exist. Start engine. With engine at idle, pinch and release PCV hose. Clicking noise should be heard. If no clicking noise is heard, ensure manifold vacuum is present. If manifold vacuum is present, replace PCV valve, and recheck.

Engine Controls - System/component Tests Acura Integra II