7.13.001  AFR  (Trouble Shooting Guide)

Purpose

The purpose of this trouble-shooting guide is to assist you in diagnosing Air Fuel Ratio (AFR) not controlling.  

Procedure

This procedure applies to all units that are currently in service in the field, at a repair shop, and in storage yards. 

Before any work is performed a JSA must be completed according to Flogistix procedure along with any customer requirements before any work is started.

                                                                                Help guide to trouble shooting the AFR Control System                                  

  This Process should help in verifying that the AFR Valve is functioning properly

        1. Does the AFR valve control the fuel mixture properly?

        2. Is the engine running rich or lean at all times?

        3. Does adjusting the ounce regulator make any difference to the AFR position?

        4. Has the O2 sensor been changed recently

Step 1. Verify that the AFR valve is wired properly in the panel and has power to the valve. 

                   In the older terminal block panels wiring should be as follows

                                             TB2 - 16 - Black or negative from the AFR valve

                                             TB2 - 17 - Red or positive from the AFR valve

                                             TB2 - 61 - purple analog signal to AFR valve

                                             TB2 - 62 - green wire or negative side of the analog

Ensure the fuse is installed on terminal TB2-61 and is not blown

If there is no power to TB2-17 check to ensure the relay CR-8 has proper power and turning on properly. 

                        1. With the compressor turned to the on position to ensure functionality, ensure wires are landed properly

                        AI-1 should be +24V AI-2 should be O:21

                        Common at 11 should be 12V or 24V depending on the compressor package

                                                                 NO on the relay should be 12V or 24V depending on the compressor package

§   If there is no power to the AI-1 input side of the relay check the F-4 fuse or trace wiring back to where power is lost, could be a loose terminal or the jumper between the relays are not seated. 

§   If there is no power to the NO side of the relay then replace the relay

§   If there is no power to the common side of relay trace wire back to main connection and replace fuse

                                 In the newer PCB board style panels wiring should be as follows

                                                 TB - 7 CR-8 NO is Red or +12/24 to the AFR valve

                                             TB - 7 PS2- is the black or negative to the AFR valve

                                             TB - 5 AO-211V+ should be the purple wire to the AFR valve

                                             TB - 5 - should be the green wire to the AFR valve

§   If there is no power to TB-7 NO ensure the relay in CR-8 is functioning properly

                                 In the new UL listed engine drive panels the wiring should be as listed

                                             TB - 2 110   Red or positive to the AFR 

                                             TB - 2 109   Black or negative to the AFR 

                                             TB - 2  69    Purple to the AFR controller

                                             TB - 2  68    Green to the AFR controller

§   If there is no power to TB2-110 check to ensure the relay CR-41 has proper power and turning on correctly. 

                        1. With the compressor turned to the on position and ensure functionality, ensure wires are landed properly

                                                             AI-1 should be +24V AI-2 should be O:21

                                                                 Common at 11 should be 12V or 24V depending on the compressor package

                                                                 NO on the relay should be 12V or 24V depending on the compressor package

§   If there is no power to the AI-1 input side of the relay check the F-4 fuse or trace wiring back to where power is lost, could be a loose terminal or the jumper between the relays are not seated. 

§   If there is no power to the NO side of the relay then replace the relay

§   If there is no power to the common side of relay trace wire back to main connection and replace fuse

                                          Step 2. If all connections and power supply in the panels are good then proceed with diagnostics

§   Check wiring on the connector of the AFR valve to ensure there are not broken wires or wires pulled from the plugin 

                                          There  are 12 pins on the connector for the AFR valve

                        Pin 1 -  red     Pin 2 - empty   Pin 3 -  green  Pin 4 - empty   Pin 5 - Black  Pin 6 - empty                                                 Pin 7 - empty   Pin 8 - empty    Pin 9 - purple   Pin 10 - empty  Pin 11 empty  Pin 12 - empty

§   Some of the older units will have a yellow wire in Pin 10, this wire is no longer used and needs to be disconnected

                                     Step 3. If the connections are good to the AFR valve plug in proceed to diagnostics of the AFR valve itself

1.        Isolate main fuel supply to the carburetor by closing the ball valve on the fuel vessel and lock out. 

2.       Remove the top of the AFR valve from the body of the valve and place in a position  where you can watch the valve operate from the panel. 

3.       Log into the PLC with the Decoder app on the HMI touch screen

4.       Go to the diagnostics page and enter the digital output test page

5.       Set the on timer for 600 seconds to give yourself plenty of time to verify the AFR valves functionality

6.       Scroll down to 102.05 - O:21 AFRC power relay and turn on the test switch. This should energize the AFR valve. 

7.       While the output test cycle is running go to the AFRC setup page 

8.       Adjust the AFRC Valve Home position from 12% to 50% to 90% and back while watching the AFR valve each change to verify it is moving properly. 

                        If the AFR  motor does not move the valve may need programmed or the valve is bad

 If the motor moves the opposite direction then intended the valve needs to be reprogrammed to clockwise on a GM 5.7 GM 8.0 and 8.3 Cummins, all 855 Cummins valves need to be programmed to counter clockwise

The 855's use a different style of valve, if the motor seems to be working properly, check inside the valve body to ensure the butterfly is not stuck in the body of the valve.

If the AFR valve motor moves as expected, then reassemble the valve and move to diagnostics of the O2 sensor and fuel supply of the compressor

 Further Diagnostic Steps are being added.  This Procedure is currently under development.

If issues continue after using this diagnostic sheet, contact your area lead for further instruction.

Responsibilities

Management - Management is responsible for implementing, supporting, and enforcing the requirements of this procedure to their respective locations/area.

EHSS - Responsible to assist in the implementation of this procedure and to review for effectiveness.

Employees, Contractors, Vendors, ETC. - Are responsible to follow the following requirements outlined in this procedure and ask for assistance

Scope

Hazards

Employees should be aware that units could contain flammable and toxic gasses.  Potential for the possible hazards of gas ignition or fire, hot surfaces & fluids, rotating equipment.  Risk of possible concentration of H2S.  Hazardous gases could be in the units pressure vessels, cooler, or associated piping and risk of inhalation of hazardous gas fumes.  Environmental spill of compressor oil and possible production fluids 

Safety

All Personal Protective Equipment (PPE) for normal Field Mechanical duties apply for this procedure.  Four Gas Monitor, which is outlined in the Flogistix EHSS Manual, PPE Section 8, Procedure 8.3 This procedure applies to all units in service in the field, at a service shop, or in any storage yard.

Insure Flogistix personnel have proper safety certification as required by the Flogistix Customer.

Insure Flogistix personnel adhere to all Customers safety practices.

Proper use of required tools 

Spills and Disposal

All spills shall be handled immediately according to MSDS recommendations and the employee's level of training

Flogistix Service Technicians performing this task will properly dispose of any waste liquids or solids.  Disposal of any fluids or solid waste will be disposed of properly according to Flogistix policy.  Disposal of any fluids will be done at an approved or designed waste location.  Disposal of solid waste from a compressor shaft seal change such as, oily rags, ETC, will be disposed of according to the local regulations regarding the disposal of oil soaked rags.    

Training

All employees shall be initially trained on the following topics:

§   Employee Personal Protective Equipment (PPE)

§   Lock Out Tag Out (LOTO) procedure according to Flogistix policy

§   MSDS Online System

§   Emergency and First Aid procedures

§   Methods and Observations that may be used to detect the presence or release of a hazardous chemicals or gas in the work place

Tools & Equipment Required

All employees performing Preventative Maintenance shall be required to have the listed tools to perform job tasks:

§   All required PPE according to Flogistix Safety Policy

§   Lock Out Tag Out LOTO items to properly perform LOTO procedure according to Flogistix policy

§   Basic Hand Tools

Approvals

Field Service approved by:

Date:

Engineering approved by:

Date:

EHSS approved by:

Date: