SECTION III - Fuel System Integrity Test

The following procedure will identify any possible sources of fuel leaks or fuel odors. If a repair or part replacement is necessary, the appropriate workshop manual should be consulted for repair procedures: The Hess & Eisenhardt manual for fuel tank related information; the XJ-S manual for information on fuel system hoses and pipes.

EQUIPMENT NEEDED

1. PRESSURE TESTING EQUIPMENT

A. Cooling System Pressure Tester Snap-On (SUT 262) or equivalent

B. Adaptors to connect pressure tester to vapor system:

a. Hess & Eisenhardt (920324) fuel filler adaptor.

NOTE:
All dealers who performed a Hess & Eisenhardt lower fuel tank recall were shipped this adaptor. A limited number of adaptors are in stock and can be purchased from Hess & Eisenhardt.

b. If for any reason the above mentioned adaptor is not on hand at the dealership, a locally purchased 1/4" nylon tee may be used to connect to the vapor system. The connection should be made at the top vapor separator hose.

2. HYDROCARBON DETECTION EQUIPMENT

When checking for possible sources of fuel leaks or odors, a hydrocarbon detector must be used (such as TIF Industries Model 8800, which is available through Zone Parts Departments under part number TIF 8800).

NOTES ON USING COMBUSTIBLE GAS "DETECTORS"

A combustible gas "detector" will detect a variety of hydrocarbons that are contained in automobiles, such as battery acid, anti-freeze, Refrigerant 12 and various adhesives. Exhaust fumes from a vehicle across the shop can also cause an incorrect detection. These examples are considered unwanted outside influences.

Do not attempt testing with detection equipment in a windy area, i.e. outside on a breezy day or near a fan (this will dissipate vapor faster than it can be detected).

Fuel vapor is heavier than air, therefore, it tends to sink to the lowest area of an enclosed compartment. Always begin odor detection by checking an upper area and work downwards.

The tip of the detector should be moved at a speed of approximately 1 inch per second, which is ideal for accurate detection.

Always triple check any area which activates the detector before any parts are condemned. If similar results are not obtained, an outside influence may have caused the initial incorrect "detector" actuation.

WARNING:
DO NOT SMOKE WHILE WORKING ON THE FUEL SYSTEM. KEEP FLAMES OR SPARKS AWAY FROM THE WORK AREA.

WARNING:
BE SURE TO DEPRESSURIZE THE FUEL SYSTEM BEFORE DISCONNECTING A FUEL LINE. DO NOT ALLOW FUEL TO DRIP ON A HOT ENGINE/EXHAUST COMPONENT.

NOTE:
TO DEPRESSURIZE THE FUEL SYSTEM REMOVE THE FUEL PUMP RELAY WHILE THE ENGINE IS RUNNING. AFTER THE ENGINE HAS STOPPED, SWITCH THE IGNITION KEY OFF.

PREPARATION FOR INTEGRITY TEST

NOTE:
The fuel system must be a minimum of 3/4 full before testing is begun (a full tank is preferable, this will minimize the amount of pumping to pressurize the tanks).

Inspect all hose fittings, pipes and components in the engine compartment and under the chassis for visible signs of seepage. If any seepage is found, repair, and continue.

FILLER CAP SEALING TEST

In order to allow the fuel to be warmed, which produces vapor and builds pressure in the fuel tank, the a/c compressor clutch wires must be disconnected disabling fuel cooling. To contain vapor in the fuel tank, disconnect the rochester valve signal hose from the B bank overrun valve stub pipe and plug the stub pipe. Bring the engine to operating temperature with the a/c compressor clutch wires disconnected, switch off the car.

To ensure vapor pressure is present in the fuel tank, gently open (crack) the fuel filler lid 1/64 of an inch and close immediately. If pressure escapes, fuel has vaporized and testing may begin. If no pressure escapes, either the fuel should be warmed further or the system is not holding pressure. To warm the fuel further, road test the vehicle or allow it to idle longer with the a/c clutch wires disconnected. In a case where pressure will not build, continue with the integrity test.

NOTE:
The fuel filler cap test should be performed after the cause of the pressure loss has been repaired.

Calibrate detector as per manufacturer's instructions.

Using the detector, check the area around the fuel cap for vapor leaks. Repair, if necessary.

INTEGRITY TEST





Using a 1/4" I.D. hose, connect the fuel tank pressure testing assembly (Hess & Eisenhardt P/N 920324) to a cooling system tester, Snap-On P/N SVT 262 or equivalent.

NOTE:
The pressure gauge must be able to display changes in pressure of 2 PSI.

Before installing the pressure gauge assembly to the vehicle, verify the assembly connections. Hold pressure for 30 seconds, by plugging the air outlet of the sealing plate an applying pressure, no pressure LOSS is permissible.

Loosen the attaching nut for the toggle bolt until the nut is 1/4" or less from the end of the bolt. Insert the toggle bolt into the filler neck and visually align the stop washer so that it is in the center of the small filler neck opening (Ref. fig. 13).

When the stop washer is centered, pull the toggle bolt up while pushing down on the sealing plate. If properly aligned, the air hose will be on the inward side of the vehicle and the toggle assembly should lock in place.

Tighten the nut until the sealing washer extrudes slightly. The pressure test apparatus must be sealed to the filler neck.





Attach a cooling system pressure tester to the Hess & Eisenhardt adaptor and pump 2 PSI into the fuel system. Observe pressure on tester pressure gauge. If 1-2 PSI is retained for 3 minutes, continue and test. If 1-2 PSI cannot be maintained in the system, the pressure vacuum valve hose should be clamped off at point "A" in fig. 14 to prevent any vapor from escaping to the charcoal canister. After the hose has been clamped off, the system should be pressurized. If pressure refuses to build, the source of the pressure leak should be found using the combustible gas detector.

To allow access when using the combustible gas detector, remove:

^ *Both lower fuel tank inspection covers;

^ *The interconnect hose cover;

^ Spare tire;

^ Metal finisher for the sump tank.

^ *Refer to the Hess & Eisenhardt repair manual for removal and installation instructions.











Using the combustible gas detector and figures 15 and 16 for reference, check the fuel system in the order shown.

Any vapor or fuel leaks should be corrected by component replacement or tightening (see torque specifications). The component in question should then be retested.

After the fuel system integrity test is complete, remove the pressure test assembly as follows:

- loosen the attaching nut for the toggle bolt until the nut is 1/4" or less from the end of the bolt.

- push the bolt in until the nut makes contact with the sealing plate.

- pull the sealing plate and washer assembly out of the filler neck.

NOTE:
It may be necessary to tilt the pressure test assembly outboard until the stop washer is visible an slide the stop washer through the small filler neck opening (fig. 13).

- reconnect the A/c compressor wires.

- Re-install:

^ the lower fuel tank inspection covers;
^ the interconnect hose cover;
^ spare tire;
^ metal finisher for the sump tank.