Engine Controls - Basic Diagnostic Procedures: Other Chevrolet Tracker II

Compression

Check engine mechanical condition with compression gauge, vacuum gauge, or engine analyzer. See engine analyzer manual for specific instructions. For compression specifications, see appropriate SERVICE & ADJUSTMENTS SPECIFICATIONS article.

Exhaust System Backpressure

Note. When performing exhaust system backpressure test, ensure transmission is in Neutral or Park. Accurate readings cannot be obtained unless vehicle remains in Neutral or Park.

1. Perform OBD system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
2. Remove HO2S1 from exhaust manifold. Install Exhaust Backpressure Tester (J-35314-A) in place of HO2S1. After tester is installed, go to next step.
3. Start engine. Monitor pressure reading on tester with engine idling in Park or Neutral. If pressure is 1.25 psi or less, go to next step. If pressure is greater than 1.25 psi, go to step 5 .
4. Increase engine speed to 2500 RPM and monitor pressure reading on tester. If pressure is greater than 1.25 psi, go to next step. If pressure is 1.25 psi or less, go to step 7 .
5. Check entire exhaust system for collapsed pipe, heat distress or possible internal muffler failure. Repair as necessary. After repairs, go to step 7 . If exhaust system is okay, go to next step.
6. Replace catalytic converter. After repairs, go to next step.
7. Allow engine to idle until normal operating temperature is obtained. Check for DTCs. If no DTCs are set, system is okay. If DTCs are set, perform appropriate diagnostic procedure for DTC set. See appropriate SELF-DIAGNOSTICS article.

NO-START - ENGINE CRANKS OKAY (2.0L)

Note. Before performing the following tests, check battery condition, engine cranking speed and for adequate fuel in tank.

BASIC FUEL SYSTEM CHECKS

Note. Begin fuel system trouble shooting and diagnosis with checking fuel injection system pressure. High fuel pressure may be present in fuel lines and component parts. Relieve fuel pressure before disconnecting any fuel system components.

Note. For terminal and circuit identification, see WIRING DIAGRAMS article.

FUEL SYSTEM PRESSURE RELIEF

Fuel system is under pressure, which must be relieved before servicing fuel system. Fuel pressure may be relieved by the following method

1. Disconnect negative battery cable. Loosen fuel filler cap to relieve fuel tank pressure. Remove fuel pump relay from junction block, behind left kick panel. Crank engine. Allow engine to start and stall. Crank engine for an additional 3 seconds to ensure fuel pressure is relieved.

1. Perform OBD system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
2. Turn ignition off. Install fuel pressure gauge. Ensure vehicle has an adequate supply of fuel. Turn ignition on with engine off. Fuel pump should run for about 2 seconds. Observe fuel pressure gauge. If fuel pressure exists, go to next step. If fuel pressure does not exist, go to step 13 .
3. Turn ignition off. Turn ignition on. Fuel pump should run for about 2 seconds. It may be necessary to cycle ignition several times to obtain maximum pressure. Observe fuel pressure gauge while fuel pump is running. If fuel pressure is 36-43 psi (2.5-3.0 kg/cm 2 ), go to next step. If fuel pressure is not 36-43 psi (2.5-3.0 kg/cm 2 ), go to step 11 .
4. Turn ignition off. Observe fuel pressure gauge for one minute after fuel pump stops. If fuel pressure holds at 25 psi (1.8 kg/cm 2 ) or greater, go to next step. If fuel pressure does not hold at 25 psi (1.8 kg/cm 2 ) or greater, go to step 7 .
5. Start engine. If vehicle starts and runs, go to next step. If vehicle does not start and run, diagnose fuel injector circuit. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article.
6. Warm engine to normal operating temperature. Observe fuel pressure gauge. If fuel pressure is 30-37 psi (2.1-2.6 kg/cm 2 ), system is okay. If fuel pressure is not 30-37 psi (2.1-2.6 kg/cm 2 ), go to step 9 .
7. Check fuel injectors, and fuel feed pipes and hoses for leaks. Repair as necessary. After repairs, go to step 19 . If no problem is found, go to next step.
8. Turn ignition on. Fuel pump should run for about 2 seconds. Observe fuel pressure gauge immediately after fuel pump stops while blocking (pinching) fuel feed hose between fuel pressure gauge and fuel pump. If fuel pressure holds at 25 psi (1.8 kg/cm 2 ) or greater, go to step 18 . If fuel pressure does not hold at 25 psi (1.8 kg/cm 2 ) or greater, go to next step.
9. Turn ignition on. Fuel pump should run for about 2 seconds. Observe fuel pressure gauge while blocking (pinching) fuel return hose. If fuel pressure holds at 25 psi (1.8 kg/cm 2 ) or greater, go to step 17 . If fuel pressure does not hold at 25 psi (1.8 kg/cm 2 ) or greater, go to next step.
10. Check for faulty or improperly operating fuel injectors. Check for leaking fuel pressure regulator. Repair or replace as necessary. After repairs, go to step 19 .
11. If fuel pressure is less than 36 psi (2.5 kg/cm 2 ), go to next step. If fuel pressure is 36 psi (2.5 kg/cm 2 ) or greater, go to step 15 .
12. Turn ignition on. Fuel pump should run for about 2 seconds. It may be necessary to cycle ignition several times to obtain maximum pressure. Observe fuel pressure gauge while blocking (pinching) fuel return hose. If fuel pressure is 57 psi (4.0 kg/cm 2 ) or greater, go to step 17 . If fuel pressure is less than 57 psi (4.0 kg/cm 2 ), go to next step.
13. Check fuel pump relay circuit. See «FUEL PUMP RELAY CIRCUIT DIAGNOSIS»(ref-129529-S27354273002001111400000) . After performing fuel pump relay circuit diagnosis, go to next step.
14. Check for restrictions in fuel feed pipe, hose or fuel filter. Check for restrictions or leaks in fuel feed pipes, hoses or connections inside fuel tank. Inspect fuel pump circuit. Ensure battery voltage is present at fuel pump connector and resistance to ground is less than 5 ohms. Repair as necessary. After repairs, go to step 19 . If no problem is found, go to step 18 .
15. Turn ignition off. Relieve fuel pressure. See «FUEL SYSTEM PRESSURE RELIEF»(ref-129529-S17745327122001111400000) . Disconnect fuel return hose from fuel pressure regulator. Connect a new fuel hose to fuel pressure regulator. Place other end of hose in approved gasoline container. Turn ignition on. Observe fuel pressure. If fuel pressure is 36-43 psi (2.5-3.0 kg/cm 2 ), go to next step. If fuel pressure is not 36-43 psi (2.5-3.0 kg/cm 2 ), go to step 17 .
16. Repair or replace restricted fuel return pipe or hose. After repairs, go to step 19 .
17. Replace fuel pressure regulator. After repairs, go to step 19 .
18. Replace fuel pump. After repairs, go to next step.
19. Operate vehicle under conditions which original symptom was noted. If system operates properly, system is okay. If system does not operate properly, see «DIAGNOSTIC AIDS»(ref-129529-S36784382622001111400000) .

BASIC IGNITION SYSTEM CHECKS

For basic ignition system checks, see appropriate diagnostic procedure under NO-START DIAGNOSIS .

IDLE SPEED & IGNITION TIMING

Ensure idle speed and ignition timing are set to specifications. For specifications and adjustment procedures, see appropriate SERVICE & ADJUSTMENT SPECIFICATIONS and ON-VEHICLE ADJUSTMENTS articles.

SUMMARY

If no faults were found while performing basic diagnostic procedures, or no trouble codes (or only intermittent ones) were found while performing OBD system check, and driveability problems still exist, proceed to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.) or intermittent diagnostic procedures.