Mechanical Gas Fuel System G5.9, G8.3 – 005-064   Exhaust Gas Oxygen Level

NOTE: This procedure applies only to engines that do not have a Cummins Air Fuel Ratio Controller.

WARNING  Natural gas is explosive and flammable. Keep cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas sharing ventilation to reduce the possibility of severe personal injury or death when working on a natural gas fuel system.

WARNING  Natural gas is lighter than air. Check the ceiling of the area where work is to be done for any possible ignition source.

WARNING  When working on a natural gas system, always have proper ventilation.

Determine the correct exhaust oxygen (O2) specification from Procedure 018-016.

Mark the power valve(s) setting(s) before starting.

Turn the power valve(s) all the way in and record the adjustment.

Turn the power valve(s) back out to previous adjustments.

By marking the setting, it is possible to return to the initial value if a problem occurs.

Remove the access plug(s) located between turbocharger outlet and muffler.

Install temporary steel line(s) at connection(s) and route to the side of the engine to allow the connection of an O2 meter.

Do not leave the O2 meter connected to the exhaust for extended periods, as moisture will accumulate and enter the O2 meter and cause erroneous readings.

Start the engine.

Reference the appropriate Operation and Maintenance manual procedure according to the application:

• G5.9: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, G5.9 Series Engine, Bulletin 4021490.
• G8.3: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, G8.3 Series Engine, Bulletin 4021489.
• G855: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, G855 Series Engine, Bulletin 4021507.
• KTA19GC: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, KTA19GC Series Engine, Bulletin 4021400.
• KTA38GC: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, KTA38GC Series Engine, Bulletin 4021588.
• GTA28: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, GTA28 Series Engine, Bulletin 4021558.
• GTA38/GTA50: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, GTA38 and GTA50 Series Engines, Bulletin 4021561.

Operate the engine until the coolant temperature reaches 60°C [140°F].

Once at operating temperature, raise the engine rpm to rated speed and 25 percent load.

If adjustments are required, turn the power valve(s) of the carburetor(s).

NOTE: If the engine has two carburetors, adjustments must be made in small increments to maintain balance between the banks. Adjust the carburetors until the exhaust oxygen contents of the banks are approximately equal and to the correct specifications.

Turn the valve(s) clockwise to lean the air/fuel mixture, which will cause the exhaust oxygen (O2) reading to increase.

Turn the valve(s) counterclockwise to richen the air/fuel mixture, which will cause the exhaust oxygen (O2) reading to decrease.

Allow adequate time between adjustments for the oxygen meter to react to the new condition. This can take up to 30 seconds.

At any point, if detonation (pinging) is encountered, reduce the load to a previous point and adjust timing.

Retarding the timing will reduce the chance of detonation, but will increase the exhaust and inlet temperatures.

Refer to Procedure 013-042.

When the correct exhaust oxygen readings are met at 25 percent load, increase to 50 percent load.

Repeat the steps to obtain the proper exhaust oxygen content.

Repeat the procedure at 75 percent and 100 percent load.

WARNING  Natural gas is explosive and flammable. Keep cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas sharing ventilation to reduce the possibility of severe personal injury or death when working on a natural gas fuel system.

WARNING  Natural gas is lighter than air. Check the ceiling of the area where work is to be done for any possible ignition source.

WARNING  When working on a natural gas system, always have proper ventilation.

Determine the correct exhaust oxygen (O2) specification from Procedure 018-016.

Mark the power valve(s) setting(s) before starting.

Turn the power valve(s) all the way in and record the adjustment.

Turn the power valve(s) back out to previous adjustments.

By marking the setting, it is possible to return to the initial value if a problem occurs.

Remove the access plug(s) located between turbocharger outlet and muffler.

Install temporary steel line(s) at connection(s) and route to the side of the engine to allow the connection of an O2 meter.

Do not leave the O2 meter connected to the exhaust for extended periods, as moisture will accumulate and enter the O2 meter and cause erroneous readings.

Natural Gas

WARNING  Natural gas is explosive and flammable. Keep cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas sharing ventilation to reduce the possibility of severe personal injury or death when working on a natural gas fuel system.

WARNING  Natural gas is lighter than air. Check the ceiling of the area where work is to be done for any possible ignition source.

WARNING  When working on a natural gas system, always have proper ventilation.

With the engine operating on natural gas, start the engine.

Reference the appropriate Operation and Maintenance manual procedure according to the application:

• G5.9: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, G5.9 Series Engine, Bulletin 4021490.
• G8.3: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, G8.3 Series Engine, Bulletin 4021489.
• G855: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, G855 Series Engine, Bulletin 4021507.
• KTA19GC: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, KTA19GC Series Engine, Bulletin 4021400.
• KTA38GC: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, KTA38GC Series Engine, Bulletin 4021588.
• GTA28: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, GTA28 Series Engine, Bulletin 4021558.
• GTA38/GTA50: Procedure 101-014 (Normal Starting Procedure) in Section 1 in the Operation and Maintenance Manual, GTA38 and GTA50 Series Engines, Bulletin 4021561.

Operate the engine until the coolant temperature reaches 60°C [140°F].

Once at operating temperature, raise the engine rpm to rated speed and 25 percent load.

If adjustments are required, turn the power valve(s) on the carburetor(s)
in small increments.

NOTE: If the engine has two carburetors, adjustments must be made in small increments to maintain balance between the banks. Adjust the carburetors until the exhaust oxygen contents of the banks are approximately equal and to the correct specification.

Turn the valve(s) clockwise to lean the air/fuel mixture, which will cause the exhaust oxygen (O2) reading to increase.

Turn the valve(s) counterclockwise to richen the air/fuel mixture, which will cause the exhaust oxygen (O2) reading to decrease.

Allow adequate time between adjustments for the oxygen meter to react to the new condition. This can take up to 30 seconds.

At any point, if detonation (pinging) is encountered, reduce the load to a previous point and adjust timing.

Retarding the timing will reduce the chance of detonation, but will increase the exhaust and inlet temperatures.

Refer to Procedure 013-042.

When the correct exhaust oxygen readings are met at 25 percent load, increase to 50 percent load.

Repeat the steps to obtain the proper exhaust oxygen content.

Repeat the procedure at 75 percent and 100 percent load.

Propane

Reduce the load on the engine to 25 percent.

Turn off the natural gas supply so that the engine is running on propane.

If adjustments are required, adjust the propane fuel flow valve(s) in small increments.

NOTE: If the engine has two propane fuel flow valves, adjustments must be made in small increments to maintain balance between the banks. Adjust the propane fuel flow valves until the exhaust oxygen contents of the banks are approximately equal and to the correct specifications.

The propane fuel flow valve(s) is(are) located after the propane regulator(s)
and before the carburetor(s).

Turn the valve(s) clockwise to lean the air/fuel mixture, which will cause the exhaust oxygen (O2) reading to increase.

Turn the valve(s) counterclockwise to richen the air/fuel mixture, which will cause the exhaust oxygen (O2) reading to decrease.

Allow adequate time between adjustments for the oxygen meter to react to the new condition. This can take up to 30 seconds.

Adjustments are complete when the meter displays the correct specifications for 30 seconds at the rated engine condition.

At any point, if detonation (pinging) is encountered, reduce the load to a previous point and adjust the propane timing.

Retarding the timing will reduce the chance of detonation, but will increase the exhaust and inlet temperatures.

Refer to Procedure 013-042.

When the correct exhaust oxygen readings are met at 25 percent load, increase to 50 percent load.

Repeat the steps to obtain the proper exhaust oxygen content.

Repeat the procedure at 75 percent and 100 percent load.