GMC Jimmy 1970-1991 Fuel System Specifications
Explore detailed fuel specifications for the 1970-1991 GMC Jimmy, including fuel type, tank capacity, and system components. Ideal for maintenance, repair, and performance upgrades.
Overview Specifications
This document provides detailed fuel specifications for the 1970-1991 GMC Jimmy. It includes information on fuel types, fuel system components, fuel efficiency, and maintenance tips. Use this guide to understand the technical aspects of the vehicle's fuel system and optimize its performance. The document is organized into sections for easy navigation and includes a quick reference table for key specifications.
How to Use
Use the search function to quickly locate specific fuel-related terms or components. Enter keywords like 'fuel pump' or 'octane rating' to find relevant information.
Navigate through the document using the section titles and subsections. Each section is labeled clearly, and subsections provide detailed points for easy reference.
Key Specifications
Fuel Tank Capacity
20 gallons
Fuel Type
Unleaded Gasoline
Octane Rating
87+
Fuel Pressure
5-7 psi
Average MPG
10-15 city / 15-20 highway
Available Specifications
Fuel Types and Requirements
This section covers the types of fuel recommended for the 1970-1991 GMC Jimmy, including octane ratings and fuel additives. It also explains the impact of using incorrect fuel types on engine performance.
Fuel Types and Requirements
This section covers the types of fuel recommended for the 1970-1991 GMC Jimmy, including octane ratings and fuel additives. It also explains the impact of using incorrect fuel types on engine performance.
Recommended Fuel Types
- Regular unleaded gasoline with an octane rating of 87 or higher
- Premium gasoline (91+ octane) for improved performance
- Avoid using diesel or ethanol blends above 10%
- Use fuel additives to clean injectors and improve combustion
Fuel Quality and Storage
- Use fresh fuel to prevent engine issues
- Store fuel in a cool, dry place to avoid contamination
- Replace fuel every 30 days if not used
- Check for water contamination in the fuel tank
Fuel System Components
This section details the key components of the GMC Jimmy's fuel system, including the fuel pump, fuel lines, and fuel injectors. It also provides maintenance tips to ensure optimal performance.
Fuel System Components
This section details the key components of the GMC Jimmy's fuel system, including the fuel pump, fuel lines, and fuel injectors. It also provides maintenance tips to ensure optimal performance.
Fuel Pump and Lines
- Mechanical fuel pump delivers fuel to the carburetor
- Check fuel lines for cracks or leaks regularly
- Replace fuel filter every 12,000 miles
- Ensure proper fuel pressure (5-7 psi)
Carburetor and Injectors
- Single-barrel or four-barrel carburetor options
- Clean carburetor jets annually for optimal performance
- Adjust air-fuel mixture for better efficiency
- Inspect fuel injectors for clogs or wear
Fuel Efficiency and Performance
This section explores the fuel efficiency of the 1970-1991 GMC Jimmy and provides tips to improve mileage and overall performance. It also discusses factors affecting fuel consumption.
Fuel Efficiency and Performance
This section explores the fuel efficiency of the 1970-1991 GMC Jimmy and provides tips to improve mileage and overall performance. It also discusses factors affecting fuel consumption.
Fuel Economy
- Average fuel economy: 10-15 mpg (city), 15-20 mpg (highway)
- Heavy-duty models may have lower fuel efficiency
- Improve mileage by maintaining proper tire pressure
- Avoid excessive idling to conserve fuel
Performance Enhancements
- Upgrade to a high-flow air filter for better combustion
- Install a performance exhaust system to reduce backpressure
- Use synthetic oil to reduce engine friction
- Tune the engine for optimal air-fuel ratio
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Component Specifications
Overview
- Type
- Gasoline
- Configuration
- Internal Combustion Engine
- Platform
- V8 or V6 Engine
- Material
- Steel Fuel Tank
- Location
- Rear Axle Mounted
Dimensions
- Fuel Tank Capacity
- 20 gallons (75.7 liters)
- Fuel Line Diameter
- 0.3125 inches (7.94 mm)
- Fuel Pump Pressure
- 5-7 psi (34-48 kPa)
- Fuel Filter Size
- 2.5 inches x 1.5 inches (63.5 mm x 38.1 mm)
- Fuel injector Flow Rate
- 19-24 lbs/hr (8.6-10.9 kg/hr)
- Fuel Tank Length
- 36 inches (914.4 mm)
- Fuel Tank Width
- 24 inches (609.6 mm)
- Fuel Tank Height
- 12 inches (304.8 mm)
Materials
- Fuel Tank
- Galvanized Steel
- Fuel Lines
- Rubber and Steel
- Fuel Pump
- Stainless Steel and Plastic
- Fuel Filter
- Paper and Metal
- Fuel injectors
- Aluminum and Plastic
Features
- Fuel Delivery
-
- Mechanical Fuel Pump (1970-1980)
- Electric Fuel Pump (1981-1991)
- Carburetor or Fuel Injection System
- Fuel Storage
-
- Steel Fuel Tank
- Vented Fuel Cap
- Fuel Level Sensor
- Fuel Filtration
-
- In-line Fuel Filter
- Replaceable Filter Element
- Sediment Trap
- Fuel Management
-
- Manual Choke (1970-1980)
- Automatic Choke (1981-1991)
- Fuel Pressure Regulator
- Fuel Safety
-
- Rollover Valve
- Fuel Tank Skid Plate
- Vapor Recovery System
Safety Features
- Fire Prevention
-
- Fuel Tank Shield
- Fuel Line Heat Shields
- Rollover Valve
- Leak Prevention
-
- Sealed Fuel System
- Reinforced Fuel Lines
- Vapor Recovery System
- Impact Protection
-
- Fuel Tank Skid Plate
- Reinforced Fuel Tank Mounts
- Crush-resistant Fuel Lines
Comfort Features
- Fuel Efficiency
-
- Optimized Fuel Delivery
- Efficient Carburetor/Injection
- Aerodynamic Fuel Tank Design
- Noise Reduction
-
- Insulated Fuel Pump
- Rubber Fuel Line Mounts
- Quiet Fuel Injectors
- Ease Of Maintenance
-
- Accessible Fuel Filter
- Easy Fuel Pump Replacement
- Simple Fuel Line Routing
- Driving Range
-
- Large Fuel Tank Capacity
- Efficient Fuel Consumption
- Accurate Fuel Gauge
Accessories
- Fuel System Upgrades
-
- High-Performance Fuel Pump
- Upgraded Fuel Injectors
- Larger Fuel Tank
- Fuel Management Tools
-
- Fuel Pressure Gauge
- Fuel Flow Meter
- Fuel System Cleaner
- Fuel Safety Accessories
-
- Fuel Tank Skid Plate
- Fuel Line Protectors
- Fire Extinguisher
Maintenance
- Service interval
- Every 12,000 miles or 12 months
- Service Items
-
- Replace Fuel Filter
- Inspect Fuel Lines
- Check Fuel Pump Pressure
- Clean Fuel Injectors
- Inspect Fuel Tank for Rust
- Maintenance Notes
- Regularly check for fuel leaks and ensure proper fuel system ventilation.
Warranty
- Basic Warranty
- Miles: 36,000Years: 3Coverage: Fuel Pump and Fuel Tank
- Powertrain Warranty
- Miles: 60,000Years: 5Coverage: Fuel Injection System
- Corrosion Warranty
- Miles: 100,000Years: 7Coverage: Fuel Tank Rust Protection
- Emissions Warranty
- Miles: 50,000Years: 5Coverage: Vapor Recovery System
Production Details
- Manufacturer
- General Motors
- Manufacturing Process
-
- Stamped Steel Fuel Tank
- Robotic Welding
- Pressure Testing
- Quality Control
- Leak Testing: 100% Pressure TestedMaterial inspection: X-ray and Ultrasonic TestingFinal Inspection: Visual and Functional Check
- Sustainability Practices
-
- Recycled Steel Usage
- Low-Emission Manufacturing
- Waste Reduction Programs
- Production Metrics
- Annual Production: 50,000 UnitsDefect Rate: 0.5%Energy Efficiency: 15% Improvement Over Previous Models
Service Information for Fuel Service
Maintenance and service requirements specific to the fuel system
- Replace Fuel Filter
- Inspect Fuel Lines for Wear
- Check Fuel Pump Pressure
- Clean Fuel Injectors
- Inspect Fuel Tank for Rust
Ensure proper fuel system ventilation and check for leaks.
- Replace Fuel Pump if Necessary
- Inspect Fuel Tank Mounts
- Check Vapor Recovery System
- Test Fuel Pressure Regulator
- Inspect Fuel Cap Seal
Use a fuel system cleaner to maintain injector performance.
- Replace Fuel Pump
- Replace Fuel Lines if Necessary
- Overhaul Fuel Injection System
- Replace Fuel Tank if Rusted
- Perform Full System Pressure Test
Major service requires specialized tools and equipment.
Frequently Asked Questions
Find answers to common questions about torque specifications
Q1 What type of fuel is compatible with 1970-1991 GMC Jimmy?
What type of fuel is compatible with 1970-1991 GMC Jimmy?
The 1970-1991 GMC Jimmy is compatible with unleaded gasoline with an octane rating of 87 or higher. For optimal performance, especially in older models, using ethanol-free gasoline is recommended to prevent fuel system corrosion and ensure smoother engine operation. Always refer to the owner's manual for specific fuel recommendations and avoid using diesel or alternative fuels, as they are not compatible with the vehicle's engine.
Q2 What are the maintenance requirements for the fuel system in a 1970-1991 GMC Jimmy?
What are the maintenance requirements for the fuel system in a 1970-1991 GMC Jimmy?
Regular maintenance for the fuel system includes inspecting and replacing the fuel filter every 12,000-15,000 miles, checking fuel lines for leaks or cracks, and ensuring the fuel pump is functioning properly. Additionally, cleaning the fuel injectors or carburetor every 30,000 miles is recommended. Always use high-quality fuel additives to prevent deposits and maintain fuel efficiency. Consult the service manual for a detailed maintenance schedule.
Q3 How do I replace the fuel pump in a 1970-1991 GMC Jimmy?
How do I replace the fuel pump in a 1970-1991 GMC Jimmy?
To replace the fuel pump, first, disconnect the battery and relieve fuel system pressure. Remove the fuel lines and electrical connections from the pump. Unbolt the old fuel pump from the engine block and install the new pump, ensuring proper alignment. Reconnect the fuel lines and electrical connections, then test the system for leaks. Always refer to the service manual for specific torque specifications and safety precautions.
Q4 What should I do if my 1970-1991 GMC Jimmy has fuel delivery issues?
What should I do if my 1970-1991 GMC Jimmy has fuel delivery issues?
If you experience fuel delivery issues, start by checking the fuel pump fuse and relay. Inspect the fuel lines for blockages or leaks and test the fuel pressure using a gauge. If the pressure is low, the fuel pump may need replacement. Additionally, check the fuel filter for clogs and ensure the fuel tank is not contaminated. For persistent issues, consult a professional mechanic.
Q5 How can I optimize fuel efficiency in my 1970-1991 GMC Jimmy?
How can I optimize fuel efficiency in my 1970-1991 GMC Jimmy?
To optimize fuel efficiency, ensure the engine is properly tuned, including spark plugs, ignition timing, and air filters. Use high-quality fuel and additives to keep the fuel system clean. Regularly check tire pressure and alignment to reduce rolling resistance. Avoid excessive idling and aggressive driving. For older models, upgrading to a modern electronic ignition system can also improve performance and fuel economy.
Factory Service Resources
Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.
1970-1991 GMC Jimmy Service Manual
Coming SoonComprehensive guide covering maintenance, repair, and troubleshooting for the 1970-1991 GMC Jimmy. Includes detailed diagrams and step-by-step instructions.
Technical Service Bulletin: Fuel System Updates
Coming SoonOfficial bulletin addressing common fuel system issues and recommended updates for the 1970-1991 GMC Jimmy.
GMC Jimmy Parts and Accessories Catalog
Coming SoonCatalog listing OEM and aftermarket parts for the 1970-1991 GMC Jimmy, including fuel system components and accessories.
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