Engine Controls - Basic Testing Dodge Spirit I

INTRODUCTION

Note. Shadow and Sundance Convertible models with 2.5L TBI engine are manufactured with either early or late design fuel, ignition and emission systems. Late design vehicles use an epoxy ignition, mounted on thermostat housing, and a high-pressure fuel system requiring quick-connect fuel fittings. Early design vehicles use an oil-filled ignition coil, mounted on right inner fender, and a low-pressure fuel system using hoses and clamps.

The following diagnostic steps 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.

VISUAL INSPECTION

Visually inspect all electrical wiring; look for chafed, stretched, cut or pinched wire. 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 ENGINE PERFORMANCE 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 engine analyzer. See engine analyzer manual for specific instructions.

DO NOT use ignition switch during compression tests on fuel injected vehicles. Use a remote starter to crank engine. Injectors on many models are triggered by ignition switch during cranking mode, which can create a fire hazard or contaminate the engine's oiling system.

ENGINE COMPRESSION SPECIFICATIONS (4-CYLINDER)

ENGINE COMPRESSION SPECIFICATIONS (V6)

EXHAUST SYSTEM BACKPRESSURE

The exhaust system can be checked with a vacuum gauge or pressure gauge. Remove O2 sensor or air injection check valve (if equipped). Connect a 1-10 psi gauge and run 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 it to intake manifold vacuum and start engine. Observe vacuum gauge. Open throttle part way and hold it steady. If vacuum gauge reading slowly drops after stabilizing, check exhaust system for restriction.

FUEL PRESSURE

Basic diagnosis of fuel system should begin with determining fuel system pressure.

ALWAYS relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components.

RELIEVING FUEL PRESSURE

1. Remove fuel tank filler cap to relieve fuel tank pressure. Install fuel tank filler cap. Place shop towels around quick-disconnect fitting to absorb spilled fuel. Disconnect injector wiring harness.
2. Using jumper wire, connect terminal No. 1 (ground) of injector harness to ground. Connect terminal No. 2 (positive) to positive battery terminal with second jumper wire. (Scheme 1)or (Scheme 2). DO NOT leave jumper wire connected to positive battery terminal longer than 5 seconds.
3. Remove jumper wires. Pressure is now fully released. Fuel injection system can be opened and fuel carrying components removed.

Scheme 1

Scheme 2

FUEL PUMP TEST SHADOW/SUNDANCE CONVERTIBLE (EARLY 2.5L TBI)

Note. Perform fuel pump test with fuel tank at least half full. Before disconnecting fuel line during testing, relieve fuel pressure. Maximum output pressure of fuel pump is 135 psi (9.5 kg/cm 2 ). Pressure is regulated at the fuel rail by pressure regulator.

1. Relieve fuel pressure. See RELIEVING FUEL PRESSURE under FUEL SYSTEM. Disconnect 5/16" fuel supply hose. Connect fuel system Pressure Gauge (C-4799-B) between fuel supply hose and engine fuel line.
2. Turn ignition on. Using Diagnostic Readout Box II (DRB-II), select ASD FUEL SYSTEM TEST to activate fuel pump. If fuel pump pressure is at specification, fuel system is functioning properly. See «FUEL PUMP PRESSURE SPECIFICATIONS»(/dodge/spirit/i-1988-1995/remont/testing-diagnostics/#engine-controls-basic-testing) .
3. If fuel pressure is as specified, record pressure and remove gauge. Install fuel pressure gauge in fuel supply line at rear of vehicle, between fuel tank and fuel filter.
4. Using DRB-II, reactivate fuel pump and record pressure reading. If fuel pressure is at least 5 psi (.4 kg/cm 2 ) higher than first pressure reading, replace fuel filter.
5. If there is no change in pressure reading, gently squeeze fuel return hose. If fuel pressure increases, replace fuel pressure regulator. If no change in fuel pressure is observed, fuel pump filter sock is plugged or fuel pump is defective.
6. If fuel pressure is greater than specification, remove fuel return hose at rear of vehicle. Connect an extension hose to return hose. Place hose in an approved container with at least a 2-gallon capacity.
7. Using DRB-II, reactivate fuel pump. If fuel pressure is now within specification, check in-tank return fuel hose for kinking. Replace fuel tank assembly if in-tank reservoir check valve or aspirator jet is plugged.
8. If fuel pressure is still greater than specification, remove fuel return hose from throttle body. Connect a substitute hose to throttle body return nipple. Place other end of hose in an approved container.
9. Using DRB-II, activate fuel pump. If fuel pressure is now within specification, check for a restricted fuel return line between throttle body and fuel tank. If no change in pressure is observed, replace fuel pressure regulator.

FUEL PUMP TEST ALL OTHER MODELS (2.2, 2.5, 3.0, 3.3 & 3.8L)

Note. Perform fuel pump test with fuel tank at least half full. Before disconnecting fuel line during testing, relieve fuel pressure. Maximum output pressure of fuel pump is 135 psi (9.5 kg/cm 2 ). Pressure is regulated at the fuel rail by pressure regulator.

1. Relieve fuel pressure. See RELIEVING FUEL PRESSURE under FUEL SYSTEM. Remove cap from fuel rail service valve (quick-disconnect fitting on 2.2L TBI, 2.5L TBI and 3.0L engines).
2. Connect Fuel System Pressure Gauge (C-4799) to fuel rail service valve or to Fuel Pressure Test Adapter (6539) on 2.2L TBI, 2.5L TBI and 3.0L engines. Turn ignition on. Using Diagnostic Readout Box II (DRB-II), select ASD FUEL SYSTEM TEST to activate fuel pump.
3. If fuel pump pressure is at specification, fuel system is functioning properly. See «FUEL PUMP PRESSURE SPECIFICATIONS»(/dodge/spirit/i-1988-1995/remont/testing-diagnostics/#engine-controls-basic-testing) . If fuel pressure is not to specification, record pressure and remove gauge.
4. Using DRB-II, reactivate fuel pump. Ensure no fuel leaks from fuel rail service valve (quick-disconnect fitting on 2.2L TBI, 2.5L TBI and 3.0L engines). Install cap on service valve.
5. If fuel pressure is less than specification, install pressure gauge in fuel supply line at rear of vehicle, between fuel tank and fuel filter, using Fuel Pressure Test Adapter (6539).
6. Using DRB-II, reactivate fuel pump. If fuel pressure is at least 5 psi (.4 kg/cm 2 ) higher than first pressure reading, replace fuel filter. If there is no change in pressure reading, gently squeeze fuel return hose.
7. If fuel pressure increases, replace fuel pressure regulator. If no change in fuel pressure is observed, fuel pump filter sock is plugged or fuel pump is defective.
8. If fuel pressure is greater than specification, remove fuel return hose at rear of vehicle. Connect Fuel Pressure Test Adapter (6541) to return hose. Place fuel pressure test adapter hose in an approved container with at least a 2-gallon capacity.
9. Using DRB-II, reactivate fuel pump. If fuel pressure is now within specification, replace fuel pump. If fuel pressure is still more than specification, remove fuel return hose from chassis fuel tubes.
10. Connect Fuel Pressure Test Adapter (6541) to return hose at chassis tube. Place fuel pressure test adapter hose in an approved container with at least a 2-gallon capacity.
11. Using DRB-II, reactivate fuel pump. If fuel pressure is now correct, check for restricted fuel return line. If no change in pressure is observed, replace fuel pressure regulator.

FUEL PUMP PRESSURE SPECIFICATIONS

FUEL PRESSURE REGULATOR

Fuel pressure regulator test procedure is not available from manufacturer. Use FUEL PRESSURE REGULATOR SPECIFICATIONS to determine correct fuel system operating pressure.

FUEL PRESSURE REGULATOR SPECIFICATIONS

IGNITION CHECKS

Note. The 2.2L TBI and all 2.5L engines are equipped with a magnetic ignition system. The 3.0L engines use an optical ignition system. The 2.2L Turbo, 3.3L and 3.8L engines are equipped with Direct Ignition System (DIS).

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

Scheme 3

1. Remove ignition coil secondary cable from distributor cap. Hold end of cable 1/4" away from a known good engine ground. Crank engine and check for spark.
2. If spark is not constant or there is no spark, go to step 4). If spark is constant, have an assistant continue cranking engine while slowly moving coil secondary cable away from ground. Observe if arcing occurs at coil tower. If arcing takes place, replace ignition coil.
3. If spark is constant and NO arcing occurs, ignition system secondary voltage is correct. Ensure secondary voltage reaches spark plugs, indicating ignition system is okay. Go to MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS. Perform tests under FUEL SYSTEM.
4. If no spark is present, ensure battery is fully charged (at least 12.4 volts). Connect voltmeter to ignition coil B+ (battery) terminal. (Scheme 3)
5. Crank engine for at least 5 seconds while checking voltage at coil terminal. If voltage remains near zero during entire cranking period, go to TESTS W/CODES article and test Auto Shutdown (ASD) relay circuit.
6. If voltmeter reading is near battery voltage, then drops to zero after 1-2 seconds of cranking, go to TESTS W/CODES article and test distributor reference pick-up circuit.
7. If voltmeter reading remains at or near battery voltage during entire cranking period, turn ignition off. Disconnect 60-pin connector from SBEC (engine controller) and check terminals for poor connections. (Scheme 4)
8. Remove positive lead from coil. Connect a jumper wire between battery positive terminal and coil positive terminal. Using a specially constructed jumper wire, momentarily ground terminal No. 19 of SBEC harness connector. (Scheme 4)and (Scheme 5). Spark should be generated when ground connection is disconnected.
9. If spark is generated, replace SBEC. If spark is not generated, ground negative coil terminal using specially constructed jumper wire. If spark is produced, repair open circuit in wiring harness. If spark is not produced, replace ignition coil.

IGNITION COIL RESISTANCE (3.0L)

Ignition coil resistance test procedure is not available from manufacturer. Use appropriate IGNITION COIL RESISTANCE under IGNITION COIL to determine correct coil resistance.

Scheme 4

Scheme 5

SPARK TEST (2.2L TBI & ALL 2.5L)

See SPARK TEST under OPTICAL IGNITION SYSTEM.

IGNITION COIL RESISTANCE (2.2L TBI & ALL 2.5L)

Ignition coil resistance test procedure is not available from manufacturer. Use appropriate IGNITION COIL RESISTANCE under IGNITION COIL to determine correct coil resistance.

DIRECT IGNITION SYSTEM

Note. On 2.2L Turbo engines, cylinders No. 1 and 4, and cylinders No. 2 and 3 are grouped together. On 3.3L and 3.8L engines, cylinders No. 1 and 4, cylinders No. 2 and 5, and cylinders No. 3 and 6 are grouped together.

SPARK TEST (2.2L TURBO, 3.3L & 3.8L)

1. Remove spark plug cable from No. 2 cylinder (No. 1 on 2.2L Turbo). Insert a known good spark plug into spark plug cable. Ground plug on engine. Crank engine and check for spark. Repeat procedure at remaining cylinders.
2. If an irregular, weak spark or no spark is present at one or more cables, go to IGNITION COIL RESISTANCE TEST (2.2L TURBO, 3.3L & 3.8L). If no spark is present, ensure battery is fully charged (at least 12.4 volts). Connect voltmeter to ignition coil B+ (battery) terminal. (Scheme 6)or (Scheme 7).
3. While cranking engine (for at least 5 seconds), check voltage at coil terminal. If voltage remains near zero during entire cranking period, go to TESTS W/CODES article and test Auto Shutdown (ASD) relay circuit.
4. If voltmeter reading is near battery voltage, then drops to zero after 1-2 seconds of cranking, go to TESTS W/CODES article and test camshaft and crankshaft position sensor circuits.
5. If voltmeter reading remains at or near battery voltage during entire cranking period, turn ignition off. Disconnect 60-pin connector from SBEC (engine controller) and check terminals for poor connections. (Scheme 4)

Scheme 6

Scheme 7

1. Remove ignition cables and measure their resistance (3000-12,000 ohms per foot). Replace cable(s) as necessary. Measure resistance of primary coil between B+ (battery) terminal and pin corresponding to cylinder(s) in question. (Scheme 6)or (Scheme 7).
2. Measure secondary coil resistance between coil towers of grouped cylinders. Replace ignition coil if primary/secondary coil resistance is not as specified. See appropriate «IGNITION COIL RESISTANCE»(/dodge/spirit/i-1988-1995/remont/testing-diagnostics/#engine-controls-basic-testing) under IGNITION COIL.

IGNITION COIL

IGNITION COIL RESISTANCE (4-CYLINDER) - Ohms @ 68°F (20°C)

IGNITION COIL RESISTANCE (V6) - Ohms @ 70-80°F (21-27°C)

IDLE SPEED & IGNITION TIMING

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

SUMMARY

If no faults were found while performing tests in this article, proceed to G -TESTS W/CODES article. If no hard codes are found, proceed to H -TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.), or intermittent diagnostic procedures.

See also:
• FUEL PUMP PRESSURE SPECIFICATIONS