Hole in gas tank - Fuel Economy, Hypermiling, EcoModding News and Forum

mrmad · 03-18-2009, 12:44 AM

I've had the Rex-O-Saurus for 2 years now which in CA means it had to pass smog - yikes. I had to get rid of the cheap Ebay intake the former owner had on there and found one on Ebay. The car passed HC and NOx, but failed the EVAP test, meaning there was an air leak somewhere in the gas tank/lines to the charcoal canister. This didn't surprise me alot, I knew if I over filled it I would smell a little gas in the car for about 10-20 miles.

I decided to replace the filler neck and all the rubber hoses on top of the gas tank which was quite a pain - had to run the car as low as I could in gas (ran it out in the driveway!) and drop the gas tank. I put it back together, robbed gas from my lawnmower and took it back to the smog station and it still failed EVAP. Being broke, I decided to hunt for the leak rather then take it somewhere. I took the tank off again and this time noticed a small screw coming through the body dead center in the top of the gas tank. The idiot former owner must have used it to try to hold the plastic "tray" that sits behind the seat and just decided to sink one right there not realizing it went right into the gas tank. This left about a 1/8" hole in the top of the tank. I found a short screw with a large head that fit the hole and JB welded the heck out of it and the tank will hold pressure. I realize this isn't a very good fix and I'll have to replace the tank eventually, but it should get the car to pass smog.

So I've been driving for two years with a hole in the top of my gas tank. Don't know how much it hurt mileage, it probably only spilled out a little when it was full and it would evaporate a little through the hole, but I'm not expecting any huge differences in mileage now that it is fixed. What irritates me is the chance the car could have caught on fire or if I got rear ended, would this screw split the gas tank open? I guess I can thank the state of CA for making me fix it, cause I wouldn't have bothered otherwise.

Christ · 03-18-2009, 01:26 AM

Quote:

Originally Posted by mrmad

I've had the Rex-O-Saurus for 2 years now which in CA means it had to pass smog - yikes. I had to get rid of the cheap Ebay intake the former owner had on there and found one on Ebay. The car passed HC and NOx, but failed the EVAP test, meaning there was an air leak somewhere in the gas tank/lines to the charcoal canister. This didn't surprise me alot, I knew if I over filled it I would smell a little gas in the car for about 10-20 miles.

I decided to replace the filler neck and all the rubber hoses on top of the gas tank which was quite a pain - had to run the car as low as I could in gas (ran it out in the driveway!) and drop the gas tank. I put it back together, robbed gas from my lawnmower and took it back to the smog station and it still failed EVAP. Being broke, I decided to hunt for the leak rather then take it somewhere. I took the tank off again and this time noticed a small screw coming through the body dead center in the top of the gas tank. The idiot former owner must have used it to try to hold the plastic "tray" that sits behind the seat and just decided to sink one right there not realizing it went right into the gas tank. This left about a 1/8" hole in the top of the tank. I found a short screw with a large head that fit the hole and JB welded the heck out of it and the tank will hold pressure. I realize this isn't a very good fix and I'll have to replace the tank eventually, but it should get the car to pass smog.

So I've been driving for two years with a hole in the top of my gas tank. Don't know how much it hurt mileage, it probably only spilled out a little when it was full and it would evaporate a little through the hole, but I'm not expecting any huge differences in mileage now that it is fixed. What irritates me is the chance the car could have caught on fire or if I got rear ended, would this screw split the gas tank open? I guess I can thank the state of CA for making me fix it, cause I wouldn't have bothered otherwise.

Since you were working on the driver's side of the car, I can imagine you already have seen this... but maybe not.

If you go out and look directly under your fuel door, under the car, stick your head up around the back left corner of the gas tank, there is a 17mm drain plug... it's the same one that's in your oil pan.

Another point of interest is that anyone put a screw through the body of your car.

Yes, the previous owner was most likely a fool. However, you might check to see just how much of a fool he was, often times people will modify seemingly simple things, or neglect seemingly unnecessary things.

Case in point for Neglect - Check your grounds. Chances are, the one that connects from the negative battery post, to the chassis, then to the transmission is corroded somewhere.

Believe it or not, just replacing the ground wires on your car will get you better gas mileage in most cases, and it's a cheap fix. Also a fix I have yet to perform on my Caravan, until I can get more 8g amplifier wire and some swage ends.

Usually, if you replace them, you'll want to upgrade them as well. Especially if you've added anything to the car that ups the current draw. Luckily, the chassis/engine ground system on your Honda CRX only consists of 2 wires, the aforementioned, and one that links your radiator support to your valve cover. The rest of the grounds are electrical grounds, loomed in with your wiring harness, and should be cleaned and covered as necessary.

If you use eBay, you can simply search for "ground wire kit" to come up with a great alternative to playing with ground wires under the hood, for around $20.

Also - check the spot where the "fool" put the screw through the body.. it might be rusting.

Ryland · 03-18-2009, 01:27 AM

next time you have to drain the gas tank look for the drain plug in the bottom, all of my civics have had one.
It should help with your mileage a little as it can burn that vapor instead of letting it lose, but it will also make your gas store longer and burn better because the lightest parts of it are not escaping.

mrmad · 03-18-2009, 01:42 AM

I knew the tank had a drain plug, I just didn't want to mess with it. I didn't need the tank to be empty to replace the hoses, filler neck, I just didn't want the weight of several gallons of gas when I lowered the tank.

99LeCouch · 03-18-2009, 05:03 PM

Plugging the gas tank is good. I need to replace the filler neck on my couch because I believe it got tweaked replacing the fuel pump, and I smell gas on the driver's side of the car (lines are on pass. side, filler neck on driver's). Or seal it with gunk of some sort.

wyatt · 03-18-2009, 05:33 PM

JB weld is not the best solution (replacing the tank is), but I will let you know that it does work. On my car I developed a crack at the bottom of the tank and used JB weld to repair it after running the car low on gas and letting it idle to dry. I basically just cleaned around the crack, sanded it to a shine, JB'd it up, sand, repeat, sand repeat until the tubes were gone. After about a year it would fall apart due to either gas exposure or the filling/emptying cycle cracking the JB weld. I eventually just replaced the tank with one I found on eBay, and have had no leaks from the tank since. You may never have a problem with it since yours is on the top of the tank, but you may want to keep in mind that it could wind up failing in a year or two or ten due to exposure to gas.