B5.9G, B5.9LPG – Troubleshooting and Repair Manual – 005-061   High Pressure Regulator, NG

The OEM or chassis manufacturer will provide a fuel manifold shutoff valve (3) and associated components needed to supply natural gas to the engine. The OEM will also provide engine coolant lines (2) plumbed to the high pressure regulator (1). This supply of warm coolant helps to prevent valve icing.

CAUTION  Before removing any fuel system component, turn off the fuel supply at the vehicle’s main gas shutoff valve.

Operate the engine at low idle until it dies.

Use INSITE™ electronic service tool to check the gas pressure (Fuel Pressure – Primary).

Operate the engine under full load conditions and measure the gas pressure.

If the pressure is below or above specifications, the vehicle’s fuel system needs to be checked. Refer to the OEM for recommendations.

Remove the elbow fitting to the fuel block inlet or the remote mount fuel filter.

Drill and tap the elbow fitting, and install a Compuchek™ pressure fitting.

Install the elbow fitting into the fuel block inlet or remote mounted fuel filter.

Install the fuel supply line to the rear cover gas inlet.

Turn on the vehicle’s main gas shutoff valve.

Use a gas detector, Part Number 3823984, or a soap solution to check all fittings for leaks.

If leaks are found, close the vehicle’s main fuel shutoff valve, turn the key to the OFF position, and repair leaks immediately.

Connect a pressure gauge with a range of 0 to 2068 kPa [0 to 300 psi].

Operate the engine under full load conditions and measure the gas pressure.

Refer to Procedure 014-002 (Engine Testing (Chassis Dynamometer)) in Section 14.

If the gas pressure is below or above specifications, the vehicle’s gas system needs to be checked. Refer to the OEM for recommendations.

Use INSITE™ electronic service tool to check the gas pressure (Gas Pressure, Primary).

Operate the engine under full load conditions and measure the gas pressure.

If the gas pressure is below or above specifications, the vehicle’s fuel system needs to be checked. Refer to the OEM for recommendations.