Honda Civic Service Manual: Manual Shut-off Valve Removal and Installation (R18A9)

1.

Raise the vehicle on a lift, and make sure it is securely supported.

This procedure should be done outside in a well-ventilated area or in a properly equipped CNG shop.

This procedure will allow you to safely work on any part of the fuel system downstream of the fuel tank such as the fuel joint block or the manual shut-off valve.

NOTE: Make sure the manual shut-off valve is open.

1.

Remove the rear seat.

2.

Remove the seat back.

3.

Disconnect the connector (A) (this prevents the tank from supplying fuel to the system).

4.

Start the engine, and let it idle.

5.

After a few minutes, the engine will stall.

6.

Turn the ignition switch to LOCK (0).

1.

Remove the rear floor undercover (A).

1.

Disconnect the fuel lines (A).

2.

Remove the manual shut-off valve (B).

NOTE: Always use two wrenches when removing the fuel line nuts.

1.

Wrap vinyl tape around the threads, and coat the surface of the tape with silicone oil or grease.

NOTE: Wrap the vinyl tape (A) so that there is no stepped portion.

2.

Install a new O-ring (A) into the groove.

NOTE: Be careful not damage the sealing face of the O-ring.

3.

Using a small brush, apply silicone oil or grease to the outer surface of the O-ring.

4.

Remove the vinyl tape.

1.

Apply silicone grease (PARKER CHRISTO-LUBE) to the new O-rings (A), and carefully install them into their proper positions.

2.

Install the manual shut-off valve (B).

3.

Connect the fuel lines (C) with new O-rings.

NOTE: Always use two wrenches when installing the fuel line nuts.

1.

Install the rear floor undercover (A).

Check for a gas leak if there is an odor coming from the vehicle. Compressed natural gas (CNG) can only be smelled, not seen.

1.

Open the hood and the fuel fill door.

2.

Connect a vacuum pump/gauge, 0－30 inHg, to the hose (A) from fuel pressure regulator P1, and apply 67.7 kPa (20.0 inHg, 508 mmHg) of vacuum.

3.

If fuel pressure regulator P2 does not hold vacuum, replace it before continuing to the next step.

4.

Inspect the fuel lines and hoses under the hood for kinks, abrasion, and other signs of damage.

5.

With the manual shut-off valve open, turn the ignition switch to ON (II), but do not start the engine.

6.

After the fuel pressure regulator shut-off solenoid valve/fuel tank internal solenoid valve operates for about 2 seconds, the fuel pressure in the fuel lines rises.

7.

Turn the ignition switch to LOCK (0).

8.

Repeat this two or three times.

9.

Within 1 minute, check for any damaged lines with a leak detector (A) (Snap-on Combustible Gas Leak Detector or Snoop Liquid Leak Detector (B)).

10.

If no damage was noticed during the inspection, turn the ignition switch to ON (II) for 2 seconds, then turn the ignition switch to LOCK (0).

11.

Within 1 minute, check for a leak at the vent hose outlet inside the fuel pipe protector (A).

12.

If you detect a leak, remove the vent hose, and check the fuel lines and fittings at the in-tank solenoid valve and the join block with a leak detector.

13.

If you cannot find the leak, raise the vehicle on a lift, remove the under-floor cover.

14.

Inspect all the fuel lines under the vehicle, visually, and with a leak detector.

15.

If you still cannot find the leak, remove the rear seat, then check all fuel lines and fittings at the fuel tank and the fuel joint block.