TERMINOLOGY
Due to federal government requirements, manufacturers may use names and acronyms for systems and components different than those used in previous years. The following table will help eliminate confusion when dealing with these components and systems. Only relevant components and systems whose names have changed from current General Motors Corp. terminology have been listed.
| Former Name Or Acronym (1) | New Name Or Acronym |
|---|---|
| ALDL | Data Link Connector (DLC) |
| CHECK ENGINE Light | Malfunction Indicator Light (MIL) |
| CTS | Engine Coolant Temperature Sensor |
| Diagnostic Circuit Check | On-Board Diagnostic (OBD) System Check |
| ESC System | Knock Sensor (KS) System |
| EST System | Ignition Control (IC) System |
| MAT Sensor | Intake Air Temperature (IAT) Sensor |
| Park/Neutral (P/N) Switch | Park/Neutral Position (PNP) Switch |
| Port Fuel Injection | Multi Port Fuel Injection |
| Scan Data | Scan Tester (ST) Data |
| SERVICE ENGINE SOON Light | Malfunction Indicator Light (MIL) |
| Thermostatic Air Cleaner (TAC) | Air Cleaner (ACL) |
| Throttle Position Sensor (TPS) | Throttle Position (TP) Sensor |
| Throttle Position Switch | Closed Throttle Position (CTP) Switch |
| Throttle Position Switch | Wide Open Throttle (WOT) Switch |
| Viscous Converter Clutch (VCC) | Torque Converter Clutch (TCC) |
| (1) Text includes old and new terminology. This is a representative listing. | |
| (1) | Text includes old and new terminology. This is a representative listing. |
SAE TERMINOLOGY CHART
Compression
Check engine mechanical condition using a compression gauge, vacuum gauge or engine analyzer. See engine analyzer manual for specific instructions. See COMPRESSION SPECIFICATIONS table.
| Application | Specification |
|---|---|
| Compression Ratio | 8.9:1 |
| Normal Compression Pressure | 199 psi (14.0 kg/cm 2 ) |
| Minimum Compression Pressure | 170 psi (12.0 kg/cm 2 ) |
| Maximum Variation Between Cylinders | 14 psi (1.0 kg/cm 2 ) |
COMPRESSION SPECIFICATIONS
Exhaust System Backpressure
Exhaust system can be checked using a vacuum or pressure gauge. If using a pressure gauge, remove O2 sensor or air injection check valve (if equipped). Connect a 1-10 psi pressure gauge. Operate engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi, exhaust system or catalytic converter is plugged.
If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port. 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 SYSTEM
| WARNING | Always relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. |
FUEL PRESSURE RELEASE
- Loosen fuel tank cap to release fuel tank pressure. Disconnect electrical connector from fuel pump relay. Fuel pump relay is mounted on ECM, located under left side of instrument panel, near kick panel. (Scheme 10)
- Start engine. Idle engine until it dies. Crank engine for about 10 seconds to ensure residual fuel line pressure is released. Reinstall fuel pump relay.
Scheme 10
FUEL PRESSURE
Note. For fuel pump specifications, see FUEL PUMP PERFORMANCE table.
Release fuel pressure. See FUEL PRESSURE RELEASE. Disconnect negative battery cable. Attach Fuel Pressure Gauge(J-34730-1) and Adapter (J-37746) at fuel filter inlet bolt. (Scheme 11) Fuel filter is located on right side of frame, above rear differential. Connect negative battery cable. Check fuel pressure. see scheme 11, see scheme 12 and see scheme 13. Release fuel pressure. Remove fuel pressure gauge. Install fuel line at fuel filter, and tighten it to 26 ft. lbs. (35 N.m).
Scheme 11
| Application | Pressure: psi (kg/cm 2 ) |
|---|---|
| Tracker | (1) 34-41 (2.4-2.9) |
| (1) With ignition on and engine off. | |
| (1) | With ignition on and engine off. |
FUEL PUMP PERFORMANCE
IGNITION CHECKS
Note. For a no-start condition, see DIAGNOSTIC CHARTS .
SPARK
Crank engine, checking for a strong Blue spark at coil wire and each spark plug wire using Spark Tester (ST-125). If spark exists on some spark plugs, check for defective distributor cap and defective rotor. Check spark plug high tension wire resistance. Replace spark plug high tension wires if resistance exceeds specification. See the HIGH TENSION WIRE RESISTANCE table.
| Application | Ohms |
|---|---|
| All Models | (1) 3000-6500 |
| (1) Resistance for every 12" (305 mm) of wire. | |
| (1) | Resistance for every 12" (305 mm) of wire. |
HIGH TENSION WIRE RESISTANCE
IGNITION COIL POWER SOURCE
Turn ignition on. Using voltmeter, check voltage between positive terminal of ignition coil (Black/White wire) and ground. If battery voltage does not exist, check for open circuit in Black/White wire between ignition coil and 15-amp ignition/meter fuse in fuse block. Fuse block is located under instrument panel, left of steering column.
| Application | Primary | Secondary |
|---|---|---|
| Tracker | 0.72-0.88 | 10,200-14,000 |
IGNITION COIL RESISTANCE- Ohms @ 68°F (20°C)
IGNITION COIL RESISTANCE
Disconnect electrical connector and ignition coil wire from ignition coil. Using ohmmeter, measure primary and secondary resistance. (Scheme 12) Replace ignition coil if readings are not within specification. See IGNITION COIL RESISTANCE table.
Scheme 12
PICK-UP COIL/CRANK ANGLE SENSOR
Measure pick-up coil/crank angle sensor air gap. If gap is not .008-.016" (.20-.40 mm), adjust or replace distributor. Check pick-up coil/crank angle sensor resistance. See I - SYS/COMP TESTS article in this section.
Scheme 13
IDLE SPEED & IGNITION TIMING
Ensure idle speed and base ignition timing are set to specification. For adjustment procedures, see ADJUSTMENTS article in this section.
CHART A-3, ENGINE CRANKS BUT WILL NOT RUN
Before using this chart, ensure battery condition, engine cranking speed and fuel quality are okay.
When ignition switch is turned to ON or START position, main relay applies battery voltage to ignition coil. If ignition coil's primary coil is being toggled to ground through ignitor, sending a signal to ECM, a high voltage is induced in secondary windings of ignition coil and is applied through distributor to spark plugs.
Note. Test numbers refer to numbers on diagnostic chart.
- Checks for trouble codes stored in ECM memory.
- Checks for spark at ignition coil.
- Checks for spark at distributor.
- Checks for spark at spark plugs.
CHART A-5, NO-START CONDITION (FUEL INJECTOR CIRCUIT CHECK)
When fuel injector solenoid coil is energized by ECM, it will activate injector plunger and pressurized fuel will be injected into throttle body. Fuel pump will operate as long as engine is cranking and ECM is receiving ignition reference pulses.
Note. Test numbers refer to numbers on diagnostic chart.
- Checks if ECM is controlling fuel injector signals.
- Checks fuel injector for correct resistance.
- Checks for an open or short to ground in Red or Yellow wire to ECM. Checks for faulty ECM.
SUMMARY
If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, go to TESTS W/CODES article in this section. If no hard codes are found in self-diagnostics, go to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.