Under I/M standards, a failed cap can cause the vehicle to fail an emissions test but not cause the Check Engine light to come on. A cap will fail if the leak size exceeds .004” hole = 60cc/min @30” H2O. Hickok/Waekon offers inspection-grade fuel cap testers designed for use in state inspection and maintenance programs. The battery-operated handheld tester electronically checks a fuel cap’s ability to hold pressure. Brightly colored LEDs indicate no leak, pass or fail test results in seconds. This kit contains the FPT2600 fuel cap tester, 10 cap adapters, pass / fail standard for daily calibration checks, vehicle lookup tables and a user guide.
Link: Hickok/Waekon