* Corrosion and Sticking: The choke mechanism itself can corrode or become gummed up with old fuel residue, varnish, or other deposits. This is the most common cause. To prevent this:
* Regular Cleaning: Periodically clean the throttle body and choke components. Use a throttle body cleaner specifically designed for this purpose and follow the instructions carefully. Pay close attention to the choke linkages and the choke plate itself.
* Lubrication: After cleaning, lightly lubricate the choke linkages with a high-quality, non-silicone-based lubricant (like a dry PTFE lubricant). Avoid excessive lubrication. Too much oil can attract dirt and worsen the problem.
* Vacuum Leaks: A leak in the vacuum lines related to the choke can cause it to malfunction or stick. Check all vacuum lines connected to the choke system for cracks, leaks, or loose connections. Replace any damaged lines.
* Choke Cable: (If your 1994 350 TBI has a cable-operated choke, which is less common on this year but possible depending on the specific setup): A stiff or frayed choke cable can prevent the choke from operating smoothly. Lubricate the cable with a suitable lubricant and inspect for damage. Replacement might be necessary if the cable is severely damaged.
* Choke Pull-Off: If the choke has a pull-off mechanism (a spring-loaded device that helps the choke open more quickly), ensure this mechanism is functioning correctly. A faulty pull-off will hamper proper choke operation.
* Temperature Sensor Issues: The engine temperature sensor can influence the choke's operation. A faulty sensor may provide incorrect temperature readings, causing the choke to stay engaged for too long or not disengage properly. Check the sensor for proper operation and replace it if necessary.
* Improper Adjustment: Some TBIs have an adjustable choke. If it's improperly adjusted, it can stick. Refer to your service manual for the correct adjustment procedure. However, most TBIs of this era had a more automatic, electronically controlled choke.
Important Considerations:
* Service Manual: A factory service manual for your specific 1994 Chevy 350 TBI is invaluable for diagnosing and addressing choke problems. It will provide diagrams, specifications, and procedures specific to your vehicle.
* Professional Help: If you're not comfortable working on your vehicle's carburetor system, it's best to take it to a qualified mechanic for diagnosis and repair. Improperly working on the fuel system can be dangerous.
By addressing these potential points, you can significantly reduce the chances of your choke sticking and ensure your engine starts and runs smoothly. Remember, preventive maintenance is key.
