I've known since my first fill up not to give that extra click in the S2K, but I never knew about this overflow stuff.. learn something new everyday

 

I'm not sure if the S2000 uses a charcoal canister for vapor recovery, but overfilling will flood whatever container the car uses, and you can end up with a damaged recovery system and have your car smell like gas, since nothing is reclaiming the fumes.

 

won't happen again.

 

I've found that some gas stations "puke" fuel into the tank when you barely squeeze the handle on the nozzle. Other stations you can gently 'trickle' the fuel in very slowly. I've found that if I fill up at a station that lets you 'trickle' the fuel in, you can EASILY put in another 2-3 gallons AFTER the pump clicks off. This equates to another 60-70 miles of range. Consequently, instead of having to fill up at 200-220 miles on the odometer, I can routinely get around 300 out of a tank. This is also the same on my '98 Blazer that I drive as a daily driver/beater -- it will take almost exactly 3 gallons after the pump clicks off the first time. The end result is that I don't have to stop and fill up as frequently. An extra 3 gallons can be an extra couple days of driving for most people.

Also, I've never had a problem with a CEL on any of my cars related to 'overfilling.'

 

I've been topping off the tanks in my '01 Integra GSR and '91 NSX ever since I got them. I go to a gas station that has pumps without the plastic housing and that allow slow flow. Once the pump clicks, I get a little more than two gallons in the tank. That's 60 miles of range. On the NSX, the filler neck is lower to the height of the fuel tank so when the pump clicks, I get only about 1/4 gallon more. Since I don't own an S2000 yet (plan to around February), I'll continue to top off the tank on that car too. I've never had any problems with the fuel delivery system in the current cars I have as well as the three Hondas I've owned before. I top off the tank for accurate measurement of my mileage. Plus I like having an absolutely full tank.

 

One time, for the heck of it, I topped off the gas right up to the brim of the neck. Half an ounce more and it would have spilt over. I got 340 miles (probably could have gone a bit more) on that tank and that's been my record so far. The first hash on the gas meter didn't go away until about 80-90 or so miles (normally I would lose the first hash at around 25 miles).

 

Aside from what it may or may not do to the car itself, here are two "real world" scenarios that will illustrate the dangers of topping up a fuel tank. I'm sure one of these will apply to almost everyone.

Scenario 1 -- I responded to a call submitted by cellphone from a passerby. A car was found parked at the side of the road with a steady dribble of fuel coming from the vicinity of the fuel door. It was a hot day, full sunshine, no wind. We arrived and sure enough, a steady flow of fuel was falling into the gutter and working it's way down the storm sewer. We removed the gas cap and siphoned a couple of gallons of fuel out of the tank. While doing this, the owner showed up. He told us that he had just filled up that morning. We asked if he had "topped up". He said he generally puts as much fuel into the tank as it will take - right up to the brim.
While being parked in the heat of the day, the fuel in the tank heated up and expanded. The expansion had no place else to go but out of the car. Since there was no wind, imagine the cool bonfire that could have resulted if someone had tossed a butt near that vehicle.

Scenario 2 -- Responded to an underground parking garage. Caller reported seeing a parked vehicle puking fuel onto the ground, creating quite a sizeable pool. It was in the middle of a very cold winter day. The garage was heated. Again, upon arrival, found a car with a fairly large pool of gasoline under and around it. The fuel was going down a sanitary sewer, so no big deal. We found out who the owner was, and had him come down. Meanwhile, we mopped up the spillage and siphoned some fuel out of the tank. The owner indicated he had just come home from the gas station where he filled it up to the brim in preparation for going on a long highway cruise later that day. He wanted the maximum cruising range possible.
Fueling the car up outside in the freezing cold made it possible to put in a good deal more fuel. When he parked it in a heated garage, the fuel expanded and fell out of the car. Once more, imagine the fireball had anyone driven by and created a spark when driving by the leaking vehicle. Sparks can easily be made if you scrape a small stone with your tire. Of course, then there's that old butt again.

With the S2000, by the nature of the design of the fuel tank and filler pipe, the average gas station fuel pump will click off when full. You will not get much more into the tank. It's really pointless to try. Doing so is foolish from so many points of view.

ps. The citizens who were at close proximity to both of these cars were lucky that the last thing they heard in their lives wasn't ....................
KAAA ........................