To fix the issue with the fuel vapor recovery system in your Series III XJ6 Jaguar, you need to address a common problem that can lead to a vacuum buildup in the fuel tank. Here’s a step-by-step explanation of the issue and how to resolve it:
Understanding the Problem
The Series III XJ6 Jaguar is equipped with a fuel vapor recovery system that captures excess fuel vapors inside a charcoal canister located in the front right fender. Sometimes, this system can become clogged, or a pressure valve may malfunction, leading to a substantial vacuum forming inside the fuel tank.
Symptoms of the Problem:
- Whooshing Sound: The most noticeable symptom is a whooshing sound when you open the fuel tank filler cap. This indicates that there is a significant vacuum inside the tank.
- Tank Deformation: As the vacuum builds, the sides of the tank may get sucked in slightly. When you open the filler cap, the tank expands back out, sometimes making a popping sound as it returns to its normal shape.
Why It’s Bad:
Repeated flexing of the fuel tank can lead to cracks and leaks over time, causing further issues and potential safety hazards.
Identifying the Culprit
The usual suspect for this issue is a small pressure valve located next to the charcoal canister. This valve is connected in line with a rubber hose leading to the canister. When this valve fails, it prevents the release of vacuum pressure, allowing it to build up in the tank.
How to Fix the Issue
Here’s how you can resolve the problem by replacing the faulty pressure valve:
Step 1: Locate the Charcoal Canister and Pressure Valve
- Open the Hood: Start by opening the hood of your Jaguar to access the front right fender area. 2. Find the Charcoal Canister: Locate the charcoal canister, which is positioned inside the front right fender.
- Identify the Valve: Look for the small pressure valve connected by a rubber hose to the canister. This valve is responsible for regulating pressure within the system.
Step 2: Inspect the Valve
- Check for Damage: Visually inspect the valve for any obvious signs of damage, wear, or malfunction.
- Test for Vacuum Release: You can perform a simple test by gently blowing through the valve to see if air passes through. If the valve is blocked, it’s likely the cause of the vacuum buildup.
Step 3: Replace the Pressure Valve
- Acquire a Replacement Valve: Unfortunately, new pressure valves are no longer available. However, you can find tested used ones on our website under part number CAC3101-USED.
- Remove the Old Valve: Carefully disconnect the rubber hose and remove the faulty valve from its position.
- Install the New Valve: Attach the replacement valve by reconnecting the rubber hose, ensuring a snug and secure fit.
Step 4: Test the System
- Run the Engine: Start the engine and let it idle for a few minutes to check for any unusual noises or symptoms.
- Open the Fuel Cap: Open the fuel filler cap to see if the whooshing sound persists. If the sound is gone, the problem has been successfully resolved.
Preventive Measures
To avoid future issues, consider the following preventive measures:
- Regular Inspection: Periodically inspect the pressure valve and charcoal canister for any signs of wear or clogging.
- Fuel Cap Checks: Monitor the behavior of the fuel filler cap and listen for any unusual sounds that might indicate a developing issue.
- System Maintenance: Keep the fuel vapor recovery system in good condition by following the maintenance guidelines outlined in your Jaguar’s manual.
By addressing the faulty pressure valve, you can prevent further damage to your Jaguar’s fuel tank and ensure that the vapor recovery system functions correctly. If you need a replacement valve, remember that tested used ones are available under part number CAC3101-USED on our website.
See our Jaguar Parts Store Catalog to order parts.
