Did you know that today’s vehicle manufacturers are not only worried about the emissions coming out the tailpipe, but also the fuel vapors from the fuel tank? Today’s cars have a complete system to collect the fuel vapor, store it and then burn that vapor instead of letting it escape into the atmosphere. This system is controlled by the computer and while you drive it will even send a little vacuum back to the tank and measures with a tank pressure sensor how long it can hold vacuum.
If it is not leaking everybody’s happy, if it is leaking the check engine light will come on. Sometimes the gas cap has been left off or loose and sometimes you actually have a leak in the system. At Fuller’s Automotive we can pressurize that system and measure the rate of leak. If it’s more than the manufactures specified limit we can find the leak with a vacuum/ EVAP/ smoke machine. We also use this machine to find really small engine vacuum leaks that would almost go undetected on today’s computer controlled engines.