Engine Controls - Basic Testing Suzuki Swift 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 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 using 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 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 vacuum leaks.

Compression

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

COMPRESSION SPECIFICATIONS

Exhaust System Backpressure

1. Check exhaust system using vacuum gauge or pressure gauge. Remove O2 sensor or air injection check valve (if equipped). (Scheme 1)& 2. Connect a 1-10 psi pressure gauge, and run engine at 2500 RPM. If exhaust system backpressure is greater than 1 3/4 - 2 psi (.12-.14 kg/cm 2 ), exhaust system or catalytic converter is plugged.
2. If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum slowly drops after stabilizing, check exhaust system for restrictions.

Scheme 1

Scheme 2

FUEL SYSTEM

FUEL SYSTEM PRESSURE RELEASE

1. Place transmission in Neutral or Park, and set parking brake. Remove fuse/relay box cover located in engine compartment, behind battery. Remove coolant reservoir from bracket.
2. Disengage harness connector from fuel pump relay from underneath fuse/relay box. (Scheme 3)& 4. Loosen fuel tank filler cap to release tank vapor pressure. Start engine, and let it idle until it dies. Crank engine 2-3 more times to ensure fuel pressure is dissipated from system. Fuel system may now be opened safely. Cover fuel line, hose or fitting using shop towel to absorb leaking fuel when loosening. When repair is completed, reconnect relay.

Scheme 3

Scheme 4

1. Release fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing__fuel-system-pressure-release). On SOHC, remove air cleaner from throttle body. Disconnect fuel hose from throttle body. On DOHC, remove ISC solenoid valve and EGR modulator bracket (if equipped). (Scheme 1)& 2.
2. On all models, install fuel pressure gauge and 3-way connector between fuel feed hose and fuel return hose. (Scheme 3)& 4. On SOHC, install air cleaner. On all models, verify battery voltage is at least 11 volts.
3. Remove fuel pump relay from fuse/relay box with harness connector installed. Fuse relay box is located in engine compartment, behind battery. Using jumper wire, connect Pink wire terminal to White/Blue wire terminal.
4. Turn ignition on. Fuel pressure should be within specification. See «FUEL PUMP PERFORMANCE»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing) table. Turn ignition off. Recheck pressure after one minute. Fuel pressure should be within specification.
5. Remove jumper wire. Install ISC solenoid valve on DOHC models. On all models, start engine and warm it to normal operating temperature. Note fuel pressure with engine idling. Fuel pressure should be within specification.
6. If pressure is not within specification, check for defective fuel pump, pressure regulator or restriction in fuel system. Repair as required. Release fuel pressure, and remove fuel pressure gauge. Reconnect fuel hoses, and check for leaks.

FUEL PUMP PERFORMANCE

Fuel Pump Circuit

Turn ignition on; leave engine off. Fuel pump should operate for 2 seconds. If fuel pump does not operate, check fuses, fuel pump control relay, fuel pump, all electrical connections and ECM. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section.

SPARK TEST

Note. On Swift DOHC, disconnect injector connector at wiring harness near engine oil dipstick before cranking engine.

1. Remove coil wire from distributor cap. Have a helper depress clutch pedal (if required). Using a high output spark tester or holding coil wire terminal end 5/16" from an engine ground, crank engine. Check for strong Blue spark from coil wire.
2. If spark does not exist, continue with ignition checks. If spark exists at coil wire, check for spark from each spark plug wire. If spark exists on one or more plug wires, check plug wire resistance. Using ohmmeter, ensure resistance of each plug wire is 3000-6700 ohms per 12" (10,000-22,000 ohms per meter). Replace any plug wire that does not test as specified.

Swift (DOHC)

1. To ensure power supply to power unit, disconnect primary wires connector at ignition coil. Turn ignition on. Using voltmeter, check voltage between coil positive terminal (Black/White wire) and ground. (Scheme 5) Battery voltage should exist. If battery voltage does not exist, check ignition fuse circuit.
2. To check power unit resistance, turn ignition off. Remove power unit from under ignition coil. Tape together two 1.5-volt batteries in series to create a 3-volt power source. Install leads to 3-volt power source. Apply negative lead to "G" terminal and positive lead to terminal IB of power unit. (Scheme 6)
3. Using ohmmeter, connect positive lead to terminal "G" and negative lead to terminal OC of power unit. (Scheme 6) Check for continuity with 3-volt power source applied to terminal IB. Check for no continuity with 3-volt power source disconnected from terminal IB. See «POWER UNIT CONTINUITY»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing) table. Replace power unit if test results are not within specification.

POWER UNIT CONTINUITY

Scheme 5

Scheme 6

IGNITION COIL RESISTANCE

IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)

Remove secondary coil wire and primary wire connector from coil. Using ohmmeter, check coil primary and secondary resistances. (Scheme 7) Replace coil if it is not within specification. See the IGNITION COIL RESISTANCE table.

Scheme 7

Swift

Disconnect harness connector from noise suppressor, located near ignitor/coil assembly. Using ohmmeter, ensure no continuity exists between terminals "A" and "B". (Scheme 8)& 9. Ensure resistance between terminals "B" and "C" is about 2200 ohms. If either test result is not within specification, replace noise suppressor.

Scheme 8

Scheme 9

PICK-UP COIL

Note. Swift DOHC uses an integral crank angle sensor within pick-up coil.

DOHC

1. Disconnect pick-up coil connector at distributor. Using ohmmeter, measure resistance between 2 upper terminals. (Scheme 10) See «PICK-UP COIL RESISTANCE»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing) table. Replace pick-up coil if resistance is not within specification. If resistance is within specification, go to next step.
2. Ensure pick-up coil has battery voltage. Disconnect pick-up coil connector at distributor. With ignition on and using voltmeter, ensure battery voltage exists at Brown/White wire terminal of connector. If voltage is not present, check wiring and connections to ECM and check ECM power supply. Repair as required. Ensure ignition coil has power. See «IGNITOR (POWER UNIT)»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing).
3. If ignition coil and pick-up coil test okay, recheck for spark. If spark is still not available, go to TESTS W/CODES article in the ENGINE PERFORMANCE Section to retrieve stored codes. Use feeler gauge to check air gap. See «PICK-UP COIL AIR GAP»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing) table. If gap is not correct, loosen signal generator mount screws and move generator to adjust air gap.

Scheme 10

Swift SOHC

1. Disconnect pick-up coil connector at distributor. With ignition on, use voltmeter to ensure battery voltage exists at harness connector Black/White wire terminal. If voltage is low or not present, check ignition fuse circuit. See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section.
2. To test resistance, remove distributor cap, rotor and dust cover. Disconnect pick-up coil Red and White wires from ignitor, noting wire positions for reassembly reference. Connect ohmmeter to Red and White wires, and measure resistance. See «PICK-UP COIL RESISTANCE»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing) table. If resistance is not within specification, replace pick-up coil. Use feeler gauge to check air gap. See «PICK-UP COIL AIR GAP»(/suzuki/swift/ii-1989-1995/remont/testing-diagnostics/#engine-controls-basic-testing) table. If gap is not correct, loosen signal generator mount screws and move generator to adjust air gap.

PICK-UP COIL AIR GAP

PICK-UP COIL RESISTANCE - Ohms @ 68°F (20°C)

IDLE SPEED & IGNITION TIMING

Ensure idle speed and base ignition timing are set to specification. If necessary, see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

IDLE SPEED SPECIFICATIONS (1)

IGNITION TIMING (Degrees BTDC @ RPM)

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, 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:
• FUEL SYSTEM PRESSURE RELEASE
• FUEL PUMP PERFORMANCE