Mitsubishi ORVR Systems
Contents
1. 17 25 Theory Module On Board Refueling Vapor Recovery How will this module help you The On Board Refueling Vapor Recovery ORVR system will soon be adopted on all vehicles sold by MMSA By completing this module you will be better prepared to diagnose and repair possible malfunctions MITSUBISHI MOTORS Technical Training SAFETY IS YOUR RESPONSIBILITY This technical training module is for use by professional Mitsubishi Motors dealership service technicians The descriptions and procedures in this publication supplement existing service manuals technical service bulletins and other documents provided by Mitsubishi Motor Sales of America Inc MMSA As a result the use of these sources may be required to ensure a proper repair Within this module you will find Notes Cautions and Warnings These references provide guidance to help you do your job efficiently and safely The definitions for these terms are listed below NOTE The purpose of a Note is to help you do your job more efficiently A Note may also provide additional information to help clarify a particular point or procedure CAUTION A Caution alerts you to the possibility of damage to either tools equipment or to the vehicle itself A Caution recommends that a procedure must be d2. Leveling Valve to Separator to Fuel Vent Valve D Canister to Assistant Vent Valve Theory Module 17 25 18 Mitsubishi Moror Sales of America Mitsubishi Motor Sales of America Inc WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION THROUGH National Institute for AUTOMOTIVE SERVICE EXCELLENCE 11 98
3. As the fuel tank cap is installed securely the shutter valve in the fuel vent valve opens the passage between the fuel cut off valve and the liquid vapor separator Theory Module 17 25 5 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Vehicle Parked Purge Air Control Valve Canister Vent Solenoid Valve IT Air Filter When fuel tank is full the leveling valve is closed by the fuel level in the tank If fuel temperature and vapor pressure increase when parked fuel vapor can pass through the fuel cut off valve fuel check valve the fuel vent valve the liquid vapor separator and into the canister The liquid vapor separator keeps liquid fuel from entering the canister Liquid Vapor Separator 2 Fuel Ch ck sas ae a E z tee A SS Tn Assistant Vent Valve Evaporative _ Emissions Canister Vent to atmosphere Fuel Check Valve Leveling Valve Fuel Tank Filler Pipe Fuel Shut Off Valve Fuel Cut Off Valve The canister traps the hydrocarbons and releases the clean air that is left out of the vent valves into the atmosphere If pressure within the tank becomes too high the check valve opens allowing excessive pressure to bleed off through the fuel cap At all times the fuel check valve passes vapor from the fuel cut off valve to the fuel vent valve Theory Module 17 25 6 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Vehi
4. ck B Leveling Valve to liquid vapor Separator to Canister C Leveling Valve to Separator to Vent Valve D Canister to Canister Vent Solenoid Valve to atmosphere Theory Module 17 25 16 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery 3 Refer to the illustration During refueling when the tank fuel level reaches a given level which valve closes to keep liquid from entering the canister A Leveling valve B Fuel shut off Valve C Fuel Vent Valve shutter D Canister Vent Solenoid Valve 4 Refer to the illustration Two technicians are discussing the role of ORVR tank Filler Cap tightening after refueling Technician A say tightening the cap opens the shutter in the Fuel Vent Valve and opens the passage between the Fuel Cut off Valve and the liquid vapor Separator Technician B says Tightening the cap closes the shutter in the Fuel Vent Valve and closes the passage between the Fuel cut off Valve and the liquid vapor Separator Who is correct A Technician A B Technician B C Both A and B D Neither A nor B Theory Module 17 25 17 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery 5 Refer to the illustration While parked what is the escape path for pressurized fuel vapor if the Canister Vent Solenoid Valve sticks closed A Fuel Cut off Valve to Check Valve to filler neck and through fuel cap B Leveling Valve to Separator to Canister C
5. cle Being Driven While driving fresh air enters the canister for purging through the air filter Purge Air Purge Line Control Valve Vapor Liquid Line Vapor Separator Air Filter Solenoid Valve Fuel Tank Fuel Shut Filler Pipe Off Valve Evaporative _ Leveling Fuel Cut Emissions Canister Valve Off Valve Leveling Valve As the fuel level decreases the leveling valve opens allowing outside air from the canister to enter the fuel tank through the liquid vapor separator This outside air keeps vacuum from forming in the tank Purging With the ORVR system purging occurs at idle and during cruise just like the strict evaporative emission systems found on other MMC vehicles Theory Module 17 25 7 Mitsubishi Moror Sales of America On Board Refueling Vapor Recovery COMPONENT OPERATION Fuel Tank Cap The fuel cap contains a two way valve to vent excessive pressure released by the fuel check valve and to prevent excessive tank vacuum build up Fuel Tank Filler Pipe Fuel Tank Filler Pipe 17 25 9 The diameter of the new fuel tank filler pipe has been reduced to 32 6mm The smaller diameter creates a liquid seal during refueling The liquid seal reduces the amount of fuel vapor escaping at the filler pipe Fuel Shut off Valve Fuel Shut Off Valve U 29 The fuel shut off valve located at the base of the fuel filler pipe opens during refueling to allow fuel to enter the fuel tank It clo
6. e opens allowing engine vacuum to purge the canister of fuel vapor This fuel vapor is then burned by the engine Theory Module 17 25 10 Mitsubishi Moror Sales of America On Board Refueling Vapor Recovery Fuel Vent Valve Leveling Valve Fuel Vent Valve 17 25 16 The fuel vent valve located inside the fuel filler neck was called the over fill limiter valve or OFLV on previous models When a fuel filler nozzle is inserted the shutter valve in the fuel vent valve blocks the passage from the fuel cut off valve This keeps fuel vapors from flowing to the canister and escaping into the atmosphere during refueling A small 3 millimeter hole in the fuel vent valve also passes some vapor to the filler neck to reduce the amount of air entering the filler neck As the fuel tank cap is securely tightened the shutter in the fuel vent valve opens the passage between the fuel cut off valve and the liquid vapor separator Leveling Valve The leveling valve is mounted in the top of the fuel tank The valve controls the level of fuel in the tank during refueling allows fuel vapor to leave the tank and enter the canister and provides fuel cut off protection The leveling valve vents through the liquid vapor separator Theory Module 17 25 Il Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Fuel Cut off Valve Fuel Cut Off Valve The fuel cut off valve formerly called the fuel
7. es that do not control refueling vapors Mitsubishi has developed an On board Refueling Vapor Recovery System which is part of the overall OBD II Evaporative control system This ORVR system keeps fuel vapors from escaping into the environment during refueling while the vehicle is parked and when the vehicle is being driven The ORVR system offers the most effective control of refueling vapors because 1 It operates in all 50 states because it travels with the car 2 It controls evaporative vapors at all times 3 It operates with any type of refueling nozzle Theory Module 17 25 3 Mitsubishi Moror Sales of America On Board Refueling Vapor Recovery APPLICATION FUNCTION 99 gt Galant 99 gt Mirage 98 gt Eclipse except GSX System controls fuel vapors at all times System monitor can set DTCs and turn on MIL in case of failure Diagnosis similar to previous EVAP systems New scan tool tests available to verify a repair U 23 17 25 4 From the drivers point of view the ORVR system operates like other evaporative emissions systems As long as the system is operating properly the driver will be unaware When a system failure occurs the OBD II systems monitor can set DTCs and turn on the Malfunction Indicator Lamp MIL to inform the driver When a malfunction occurs system diagnosis is similar to previous EVAP emission control systems however there are new scan tool tests t
8. o help you quickly verify a repair Theory Module 17 25 4 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery SYSTEM OPERATION Purge Air Purge Line During refueling the Fuel filler nozzle moves the shutter valve in the fuel Vent Valve previously called the OLFV Over Fill Limiter Valve This closes the passage between the Fuel Cutoff Valve and the Liquid Vapor Separator A small 3mm hole in the shutter valve allows some fuel vapor from the tank to recirculate into the fuel filler neck This reduces the amount of fresh air drawn into the filler neck during refueling Control Valve Vapor Line Liquid Air Filter Canister Vent Solenoid Valve Vapor Separator Fuel Tank Filler Pipe Fuel Shut Off Valve Evaporative Leveling Fuel Cut Emissions Canister Valve Pressure in tank Leveling Valve Fuel Shut off Valve Fuel Vent Valve Shutter Valve Off Valve As the tank is filled pressure builds up inside the tank This pressure forces vapor in the tank to pass through a leveling valve to a liquid vapor separator and then to the canister The canister traps the hydrocarbons and releases clean air out of the vent valves into the atmosphere When fuel reaches a given level the leveling valve closes to keep liquid fuel from entering the canister When fuel stops flowing into the tank the fuel shut off valve also closes to keep fuel from flowing back up the filler pipe
9. one in a certain way to avoid potential problems resulting from improper technique or method AN WARNING A Warning alerts you to the highest level of risk Warnings inform you that a procedure must be done in a particular way to minimize the chances of an accident that could result in personal injury or even loss of life When you see a Note Caution or Warning be sure you understand the message before you attempt to perform any part of a service procedure Also keep in mind it is impossible for MMSA to anticipate or evaluate every service situation a technician may encounter For that reason you have the final responsibility for personal safety yours and those working around you Be sure to always wear proper protective clothing and safety equipment use the proper tools and follow the repair procedures as outlined in various service publications provided by MMSA No part of this publication may be reproduced stored electronically or transmitted in any form or by any means without prior written approval from Mitsubishi Motor Sales of America Inc MMSA reserves the right to make changes in the descriptions specifications or procedures without prior notice or obligation Copyright 1998 Mitsubishi Motor Sales of America Inc Corporate Technical Training Department On Board Refueling Vapor Recovery MODULE GOAL Upon completion of this module you will be able to identify the unique design characteristics that affec
10. operly and is not bent sticking or inoperative In this Module you have learned how the On Board Refueling Vapor Recovery system or ORVR operates during refueling while the vehicle is parked and when the vehicle is being driven In addition you have learned the names of the ORVR system components where they are located and the role that each plays in the operation of the ORVR system Finally you have been given a list of important things to remember about the operation of the ORVR system When using the scan tool this knowledge will help you properly diagnose and repair any ORVR related problems you might encounter with greater speed and accuracy Theory Module 17 25 15 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery KNOWLEDGE CHECK Choose the answer you think is the most correct 1 Why does the ORVR system offer the most Feedback effective control of refueling vapors A B Purge Air Purge Line Control Valve ae Canister Vent Air Filter Solenoid Valve It operates in every state It controls vapors at all times It operates with any type of refueling nozzle All of the above Liquid Vapor Separator Fuel Tank Filler Pipe Fuel Shut Off Valve Evaporative Levelin Fuel Cut Emissions Canister Valve g Off Valve 2 Refer to the illustration During refueling what is the flow path for fuel vapor in the tank A Fuel Cut off Valve to Check Valve to filler ne
11. rollover valve is mounted in the top of the fuel tank It allows an additional vapor path to the liquid vapor separator and keeps the canister from being saturated with fuel during a rollover Assistant Vent Valve Assistant Vent Valve The assistant vent valve is located between the air filter and the canister vent solenoid valve This mechanical valve is spring loaded to the closed position If the air filter should become clogged the valve moves off its seat to vent the system In addition the valve provides an exit for air during refueling operations Theory Module 17 25 12 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Canister Vent Solenoid Valve Canister Vent Solenoid Valve The canister vent solenoid valve is located in the line between the assistant vent valve and the vent side of the canister It is used for the MMC and Chrysler OBD II leak detection systems When performing an evaporative emissions system leak check on vehicles with the MMC ORVR system the valve closes allowing the engine to pull vacuum on the fuel tank When performing an evaporative emissions system leak check on vehicles with the Chrysler ORVR system the valve closes to allow the leak detection pump LDP to pressurize the system The valve is open at all other times Theory Module 17 25 13 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Fuel Check Valve Air Fil
12. ses after refueling to keep liquid fuel from splashing up the fuel tank filler pipe Theory Module 17 25 8 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Vapor Return Line Vapor Line Evaporative Emissions Canister The fuel vapor return line located between the liquid separator and the fuel filler pipe routes fuel vapor under pressure into the fuel filler pipe This reduces the amount of outside air drawn into the filler neck during refueling Vapor Line The fuel vapor line located between the liquid vapor separator and the canister has a larger bore to reduce the resistance of fuel vapor flow Evaporative Emissions Canister 17 25 13 The canister is larger 2 3L capacity and operates the same as before Theory Module 17 25 9 Mitsubishi Moror Sales of America On Board Refueling Vapor Recovery Liquid Vapor Separator Purge Air Control Valve The liquid vapor separator is mounted outside the fuel filler pipe Its purpose is to keep liquid fuel from entering the canister During an abrupt turn it is possible for liquid fuel to exit the leveling valve and travel through the system A standpipe inside the separator traps the liquid fuel allowing only fuel vapor to travel to the canister Purge Air Control Valve The purge air control valve is connected to the canister and the engine vacuum line At appropriate times the solenoid operated purge air valv
13. t performance diagnosis and maintenance of the On board Refueling Vapor Recovery ORVR system After completing this module you will be able to Identify the benefits of an ORVR system over a conventional Strict Evaporative Emissions system Describe the ORVR system operation during refueling while the vehicle is parked while the vehicle is being driven Identify the location and purpose of each of the ORVR components WHAT YOU WILL NEED This module DIRECTIONS Read through this material carefully Study each illustration as you read Be able to answer the knowledge check questions at the end of this module TIME TO COMPLETE About 30 minutes Theory Module 17 25 I Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery Module Signposts Refer to the related video material for more information Refer to the related publication for more information Reference Perform the related activity and answer the related questions Complete the Knowledge Check to verify P your understanding of the material Theory Module 17 25 2 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery OVERVIEW Dual Pump Hoses On Board Refueling Vapor Recovery During refueling uncontrolled systems allow hydrocarbons to escape as the vehicle tank is filled To prevent this some states require the use of dual refueling pump hoses Other states continue to use refueling hos
14. ter The fuel check valve has been added between the fuel vent valve and the fuel cut off valve During normal operation the fuel check valve allows vapor to travel to the fuel vent valve shutter but not to the filler neck If pressure within the tank becomes higher than normal the valve opens allowing excessive pressure to bleed off through the fuel cap Air Filter 17 25 22 An air filter has been added to the vent side of the system to filter incoming air before it enters the canister Theory Module 17 25 14 Mitsubishi Motor Sales of America On Board Refueling Vapor Recovery SERVICE TIPS No kinked or pinched hoses All hoses connected properly Use only factory parts Inspect vent valve for proper operation SUMMARY When you are diagnosing or repairing a vehicle that is equipped with an on board refueling vapor recovery ORVR system be aware that Take care when you install hoses to ensure that are not kinked or pinched All vapor hoses must be connected A disconnected vapor hose will cause the MIL to come on All vapor hoses and pipes should be replaced with genuine Mitsubishi parts Using improper parts can result in the creation of a liquid sump in a vapor line This condition can cause the MIL light to come on and refueling problems Check the fuel vent valve for smooth operation refer to the Service Manual Inspect the fuel vent valve flapper to ensure that it seats pr
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