are you a typical human. do you feel the need to cram as much fuel as the vehicle will take. are you standing at the gas pump inching those last few pennies of gas into your resevoir. STOP. this can permanently damage your vehicles fuel system and potentially cost you a lot of money.
The reason this is a NoNo is fairly simple, but a brief background of the operation of the systems involved is necessary.
Here we Go......
First and foremost the system that is most affected is the EVAP system. The Evaporative Emissions System is designed to remove the fuel vapors from the tank, filter them, them send them into the engine at the right time to be burned. On new vehicles,(1996+) it was decided to design a system to extract the vapors from the fuel tank and have them be used by the engine for combustion. This system employs a myriad of components, the components we will be focusing on today are the Charcoal Canister and the Leak Detection Pump. Most vehicles will have some iteration of these devices.
Now, when you are dripping those last few ounces of fuel into the filler neck, you are essentially flooding the vent tube system on the tank. These hoses are NOT designed to handle liquid fuel and leaks can result. This also affects the Charcoal Canister(CC). This is another device that WILL NOT handle fluid. The CC is the most damaged item here. Raw fuel destroys the activated charcoal in this filter and it's performance will degrade to the point of complete ineffectiveness, normally resulting in a Check Engine Light. There are also a number of check-valves that can be harmed, but this is rare.
The other problem is with the LDP. This system continually checks the fuel tank and associated systems for any kind of leak by PRESSURIZING the fuel tank. If this system cannot pressurize the tank(too full!!), it will also register a Check Engine Light. It is aslo possible for the raw fuel too creep up to this pump and destroy the motor. Again, another check engine light.
There is one way to prevent this, when the handle of the gas pump clicks, YOU ARE FINISHED. DO NOT FILL further. Easy huh?.?.?.?.?
Now, I don't know where you work, but diagnosis for a check engine light here is $74.00
That DOES NOT INCLUDE repair, only scanning the vehicle and clearing the light. This kind of fault is not easily duplicated, but any competent shop should know what an overfilled tank can do and recognize the associated faults. Too bad there are not may competent shops.......
guess that is it, just felt like ranting about something i see everyday