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EVAP/LOW PRESSURE SAFETY
The procedures in this section are intended to be basic guidelines for users to practice using the
Speed Smoke Diagnostic Leak Locator (EVAP / Low Pressure mode)
This operation manual is not intended to be used in place of common sense:
• Use this equipment in the manner specified by the manufacturer
• Understand operating procedures
• Follow all safety precautions
!
DO NOT USE TURBO / HIGH PRESSURE IN EVAP SYSTEM
SAFETY PRECAUTIONS
!
• All diagnostic work should be performed with the engine off
• Do not leave a vehicle unattended while equipment is connected or operating
• Equipment operates on a AC Voltage
• Do not perform tests near a source of spark of ignition
• When working with the fuel system, work in a well-ventilated area
• Always wear the appropriate safety protection. Wear OSHA standard eye wear and protective
gloves when using this equipment
EVAP/LOW PRESSURE
How To Diagnose EVAP Leaks
Leaks in the EVAP system, or fuel vapor recovery system, are frequently the cause of check engine
lights. Using a diagnostic leak detector, these leaks can be quickly diagnosed and repaired, making them
profitable services for repair facilities
PRESSURE DECAY / LEAK DOWN TEST
1. Verify if a leak is currently present, test the EVAP system using the Decay or Leak Down testing method
with air only
a. To access the EVAP service port, remove the green cap
Remove Schrader valve using the provided Schrader Valve Removal Tool
(Schrader valve has left-handed threads, turn clockwise to remove)
b. Using a scan tool, close the vent solenoid to close EVAP system from
atmosphere (If vent solenoid does not close, intermittent solenoid may have failed)
c. Input air into EVAP system until fully pressurized. When pressure gauge reaches its maximum
pressure (12-14 inches of water column), Flow Meter will indicate leak size (if leak is present)
d. Lock out system by turning the Flow Control Knob to the fully closed position. Observe pressure
gauge for decay
e. If no leaks are present, system will hold pressure
f. If pressure decays or leaks down, leaks exist. Proceed to step 2 to find leaks
2. Remove the fuel cap
3. Open Flow Control Valve to input vapor into the system through adaptor
4. Replace fuel cap when dense vapor is seen exiting the filler neck
5. Continue pumping vapor into the system
6. Using the provided Halogen Inspection Light, inspect for leaks (under the hood and tracing the route of
the EVAP system on the underside of the vehicle)
7. Repair the system as needed
8. Repeat procedures in steps above until all repairs are complete and final quality test is performed,
indicating no leaks
6
TESTING FOR LEAKS
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