Engine Controls - Basic Testing Acura Integra II

INTRODUCTION

The following diagnostic steps will help prevent overlooking a simple problem. This is also where to begin diagnosis for a no-start condition.

The first step in diagnosing any driveability problem is verifying the customer's complaint with a test drive under the conditions the problem reportedly occurred.

Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test listed in this article.

Note. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. See VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

Compression

Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions.

ENGINE COMPRESSION (1)

Exhaust System Backpressure

The exhaust system can be checked with a vacuum or pressure gauge. Remove O2 sensor or air injection check valve (if equipped). Connect a 0-5 psi pressure gauge and operate engine at 2500 RPM. If exhaust system backpressure is greater than 1 3/4-2 psi, exhaust system or catalytic converter is plugged.

If a vacuum gauge is used, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after stabilizing, check exhaust system for restriction.

FUEL PRESSURE

Begin basic diagnosis of fuel system with determining fuel system pressure.

Note. Before disconnecting the battery, obtain the activation code to reset the anti-theft stereo (if equipped).

Relieving Fuel Pressure

Remove negative battery cable. Loosen fuel tank filler cap. Place clean shop rag around fuel filter. Slowly loosen 6-mm service bolt, on top of fuel filter, one complete turn to relieve system pressure. Always replace washer under 6-mm bolt after loosening.

Pressure Testing

1. After relieving fuel pressure, connect Fuel Pressure Gauge (07406-0040001 ) at 6-mm service bolt location. Reconnect negative battery cable. Start engine and note fuel pressure on gauge. If vehicle will not start, but has spark and no fuel pressure, inspect fuel pump relay. REGULATED FUEL PRESSURE Application At Idle W/O Vacuum psi (kg/cm 2 ) At Idle W/Vacuum psi (kg/cm 2 ) All Models 37-46 (2.6-3.2) 35-37 (2.4-2.6)
2. Disconnect vacuum hose from pressure regulator (fuel pressure gauge should rise) and inspect for manifold vacuum. If vacuum is not present, check for restriction in vacuum port or hose. Plug vacuum hose and check fuel pressure gauge. Gauge should indicate 37-46 psi (2.6-3.2 kg/cm 2 ).
3. If pressure is higher than specified, check for pinched or clogged fuel return line between fuel rail and fuel tank. If no problem is found in fuel line, replace pressure regulator.
4. If pressure is lower than specified, check for plugged fuel filter. If filter is not plugged, lightly pinch off fuel return line. If fuel pressure does not rise, replace fuel pump. If fuel pressure rises, replace pressure regulator.

Fuel Pump Relay (Integra)

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

Scheme 1

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

Fuel Pump Relay (Legend)

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

Scheme 2

1. Remove fuel pump main relay located at left side of cowl. Connect battery voltage to terminal No. 4, and ground to terminal No. 8 of main relay. (Scheme 2)
2. Check continuity between relay terminals No. 5 and No. 7. If continuity exists, go to next step. If continuity does not exist, replace relay.
3. Connect battery positive to relay terminal No. 6, and battery negative to terminal No. 2. Check continuity between relay terminals No. 1 and No. 3. If continuity exists, go to next step. If continuity does not exist, replace relay.
4. Connect battery positive to relay terminal No. 3, and battery negative to terminal No. 8. Check continuity between relay terminals No. 5 and No. 7. If continuity exists, relay is okay. If continuity does not exist, replace relay.

SPARK

Check spark at secondary coil wire and at each spark plug wire using a spark tester. Check spark plug wire resistance on suspected wires. Resistance should not be more than 25,000 ohms.

IGNITION COIL POWER SOURCE

1. On Integra, remove distributor cap. On all models, disconnect ignition coil primary leads. Turn ignition on. Using voltmeter, check voltage between ground and Black/Yellow wire terminal of ignition coil harness (six coils on Legend). (Scheme 4)and (Scheme 5).
2. Ensure battery voltage exists. If battery voltage does not exist, check for open in Black/Yellow wire between ignition coil and ignition switch. A radio noise condenser is used on the Black/Yellow wire. If condenser is shorted, power supply will be interrupted and vehicle will not start.

IGNITOR POWER SUPPLY (INTEGRA)

1. Turn ignition off. Disconnect harness from ignitor. Turn ignition on. Using voltmeter, check for battery voltage between ground and Black/Yellow wire of harness. (Scheme 4)
2. If voltage is not present, check for open in Black/Yellow wire between ignition coil and ignitor harness connector. If wire is okay, check ignition coil power source and ignition coil resistance. Also check radio noise condenser for internal short to ground.

Scheme 3

1. Turn ignition off. Disconnect harness from ignitor. Using ohmmeter, check for continuity between Black wires and ground. If continuity does not exist, check for open wire or bad ground connection.
2. Turn ignition on. Using voltmeter, check for battery voltage between ground and each White wire, including White wire with tracer color, of harness. (Scheme 3) If voltage is not present, check for open in wire between ignition coil(s) and ignitor harness connector. If wire(s) is okay, check ignition coil power source and ignition coil resistance. Also check radio noise condenser for internal short to ground.

IGNITION COIL RESISTANCE (INTEGRA)

1. Remove distributor cap. Remove screws retaining primary ignition leads. Remove primary leads from ignition coil. Using an ohmmeter, check resistance between primary terminals "A" and "B" on ignition coil. (Scheme 4) Resistance should be.6-.8 ohm at 70°F (20°C).
2. Check secondary resistance between terminal "A" and secondary terminal (coil tower). Resistance should be 9760-14,640 ohms at 70°F (20°C). Replace coil if readings are not within specifications.

Scheme 4

Scheme 5

1. Remove harness from ignition coil. Using an ohmmeter, check resistance between primary terminals "A" and "B" of ignition coil. (Scheme 5)
2. Resistance should be.99-1.1 ohms at 77°F (25°C). Replace coil if resistance is not within specification. Resistance value for secondary winding is not available. IGNITION COIL RESISTANCE Ohms @ 68°F (20°C) Application Primary Secondary Integra.6-.8 9760-14,640 Legend.99-1.1 (1) (1) Information is not available from manufacturer.

Scheme 6

Scheme 7

1. Timing control and triggering of the fuel injectors are based on input signals from the TDC/CRANK/CYL sensors. These sensors are simple Permanent Magnet (PM) generator pick-up coils.
2. Using a DVOM (preferably with bar-graph function) on low-volt scale, check each sensor for pulse voltage signal at indicated ECU harness terminals with engine cranking. See «ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS»(/acura/integra/ii-1989-1993/remont/testing-diagnostics/#engine-controls-basic-testing) table. If pulse signal is present, sensor is okay. If pulse signal is not present, go to next step.
3. Ensure ignition is off. Check wiring connections. Check resistance of each sensor at indicated ECU harness terminals. See «ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS»(/acura/integra/ii-1989-1993/remont/testing-diagnostics/#engine-controls-basic-testing) table. If resistance is not within specification, go to step 5). If resistance is within specification, go to next step. ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS Application ECU Terminals (1) Resistance Integra CRANK B10 & B12 350-700 Ohms CYL C1 & C2 350-700 Ohms TDC C3 & C4 350-700 Ohms Legend CRANK No. 1 B15 & B16 600-950 Ohms CRANK No. 2 B14 & B13 600-950 Ohms CYL No. 1 B12 & B11 600-950 Ohms CYL No. 2 B9 & B10 600-950 Ohms (1) Terminal identifications are imprinted on ECU connector.
4. Check continuity to ground on each terminal. If continuity exists, 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.
5. Disconnect sensor connector at sensor. (Scheme 6)and (Scheme 7). Check resistance of sensor. See «ECU INPUT SIGNAL & RESISTANCE TEST TERMINALS»(/acura/integra/ii-1989-1993/remont/testing-diagnostics/#engine-controls-basic-testing) tables. If resistance is within specification, repair open, short or corrosion in sensor harness between ECU and sensor. If sensor resistance is not within specification, replace sensor assembly.

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

IDLE SPEED SPECIFICATIONS

IGNITION TIMING (Degrees BTDC @ RPM)

SUMMARY

If no faults were found while performing BASIC TESTING , proceed to TESTS W/CODES article in the ENGINE PERFORMANCE Section. If no hard codes are found in self-diagnostics, or vehicle does not have a self-diagnostic system, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

See also:
• BASIC TESTING
• TESTS W/O CODES