INTRODUCTION
Use this article to quickly find specifications related to servicing and on-vehicle adjustments. This article may be used for quick reference when you are familiar with proper adjustment procedures and only need a specification.
MODEL IDENTIFICATION
Vehicle model is identified by fifth character of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.
| Series (1) | Model |
|---|
| "C" | Sierra, Suburban |
| "G" | Van |
| "K" | 4WD Pickup, Sierra Pickup, Suburban |
| "P" | Commercial Van/Motorhome |
| (1) Vehicle series is fifth character of VIN. |
| (1) | Vehicle series is fifth character of VIN. |
CAPACITIES
| Application | Cold Cranking Amps @ 0°F (-18°C) | Reserve Capacity (Minutes) |
|---|
| 7.4L (VIN N) | 630 | 115 |
| Application | (1) Quantity - Qts. (L) |
|---|
| Crankcase | (2) 7.0 (6.6) |
| Cooling System (Includes Heater) (3) |
| Standard | 23.0 (22.0) |
| Heavy Duty | 27.0 (26.0) |
| Automatic Transmission (Dexron-II) (4) | 5.0 (4.7) |
| Manual Transmission |
| 4-Speed | (5) 4.0 (3.8) |
| 5-Speed | (6) 2.2 (2.0) |
| (1) Fluid capacities listed are approximate. Always fill to FULL mark. (2) Includes oil filter capacity. (3) Add 3 qts. (2.8L) coolant for models equipped with rear heater. (4) Drain and refill capacity only. Does not include torque converter. (5) GL-4. (6) Manual Transmission Fluid (T2850). |
| (1) | Fluid capacities listed are approximate. Always fill to FULL mark. |
| (2) | Includes oil filter capacity. |
| (3) | Add 3 qts. (2.8L) coolant for models equipped with rear heater. |
| (4) | Drain and refill capacity only. Does not include torque converter. |
| (6) | Manual Transmission Fluid (T2850). |
SERVICE INTERVALS & SPECIFICATIONS
| Component | Interval (Miles) |
|---|
| Air Filter | 30,000 |
| Coolant | 30,000 |
| Fuel Filter | 60,000 |
| Oil & Filter | 7500 |
| Spark Plugs | 30,000 |
BELT TENSION
| Application | Tension - Lbs. (kg) |
|---|
| 7.4L (VIN N) | (1) |
| (1) Serpentine belt tension is maintained automatically by a spring-tensioned idler pulley. No adjustment is necessary. |
| (1) | Serpentine belt tension is maintained automatically by a spring-tensioned idler pulley. No adjustment is necessary. |
ENGINE COMPRESSION
| Application | Compression Ratio |
|---|
| 7.4L (VIN N) | 7.9:1 |
VALVE CLEARANCE
Note. All models are equipped with hydraulic lifters. No adjustments are required.
IGNITION COIL
| Application | Ohms |
|---|
| 7.4L (VIN N) | 500-1500 |
HIGH TENSION WIRE RESISTANCE
| Application | Ohms |
|---|
| 7.4L (VIN N) | 30,000 Maximum |
HIGH TENSION WIRE RESISTANCE
SPARK PLUGS
| Application | AC |
|---|
| 7.4L (VIN N) | CR43TS |
| Application | Gap - In. (mm) | Torque - Ft. Lbs. (N.m) |
|---|
| 7.4L (VIN N) | .035 (0.89) | 11 (15) |
SPARK PLUG SPECIFICATIONS
FIRING ORDER & TIMING MARKS
Note. For firing order and timing marks (Scheme 3)
Firing Order & Timing Marks (7.4L VIN N). Scheme 3
Scheme 3: Firing Order & Timing Marks (7.4L VIN N)
IGNITION TIMING
Note. For timing adjustment procedures, see ADJUSTMENTS - 7.4L article in the ENGINE PERFORMANCE section.
| Application | (1) Man. Trans. | (2) Auto. Trans. |
|---|
| 7.4L (VIN N) | 4 @ Idle | 4 @ Idle |
| (1) With transmission in Neutral. (2) With transmission in Neutral or Park. |
| (1) | With transmission in Neutral. |
| (2) | With transmission in Neutral or Park. |
FUEL PUMP
| Application | Psi (kg/cm 2 ) |
|---|
| 7.4L (VIN N) | 26-32 (1.8-2.2) |
INJECTOR RESISTANCE
| Application | Ohms |
|---|
| 7.4L (VIN N) | 1.3 |
| (1) Injector resistance specification is at 140°F (60°C). |
| (1) | Injector resistance specification is at 140°F (60°C). |
INJECTOR RESISTANCE SPECIFICATIONS (1)
IDLE SPEED & MIXTURE
Note. Idle mixture on fuel injected models is controlled by Electronic Control Module (ECM) and is not adjustable. Controlled idle speed and IAC count can be checked using scan tester. See CONTROLLED IDLE SPEED & IAC COUNT table.
| Application | Idle RPM | (1) IAC Counts |
|---|
| Auto. Trans. (2) | 675 | 5-30 |
| Man. Trans. (3) | 800 | 5-30 |
| (1) Add 2 counts for engines with less than 500 miles. On 4.3L and V8 engines, add 2 counts for every 1000 ft. above sea level. (2) Automatic transmission in Drive. (3) Manual transmission in Neutral. Tech 1 scan tester will display "RDL" with transmission in Neutral. |
| (1) | Add 2 counts for engines with less than 500 miles. On 4.3L and V8 engines, add 2 counts for every 1000 ft. above sea level. |
| (2) | Automatic transmission in Drive. |
| (3) | Manual transmission in Neutral. Tech 1 scan tester will display "RDL" with transmission in Neutral. |
CONTROLLED IDLE SPEED & IAC COUNT
MINIMUM IDLE SPEED
Note. Minimum idle speed adjustment can only be performed on 7.4L engines. For minimum idle speed adjustment procedures, see ADJUSTMENTS article.
| Application | (1) RPM |
|---|
| Automatic Trans. (2) | 600-650 |
| Manual Trans. (3) | 675-725 |
| (1) Idle speed with seated IAC is lower than specified if engine has less than 500 miles or when checked at altitudes above 1500 feet. (2) Automatic transmission in Drive. (3) Manual transmission in Neutral. |
| (1) | Idle speed with seated IAC is lower than specified if engine has less than 500 miles or when checked at altitudes above 1500 feet. |
| (2) | Automatic transmission in Drive. |
| (3) | Manual transmission in Neutral. |
