silvercivic

Hi, I've got a 90 civic si. I discovered that a line leading into the gas tank is leaking. It's been replaced with a rubber hose so the leak has stopped for now, (it was originally metal) but I really need to know if it's the pressure line or the return line. It is found by removing the driver's side rear tire. It is between the rear drum brake and the gas tank, and is covered by a plastic cover being held in place by a couple of bolts and plastic fasteners. The line is by itself, and there are no other lines visible. It leads to the gas tank and is mostly steel. The only part that is rubber is a short hose that leads into the fuel tank. After that it is steel that leads to a banjo bolt near the rear drum brake, then from the bolt, it is more steel all the way to the front of the car. Here are some observations that I've found that may or may not indicate what it is.

Reasons it could be the pressure line:
i) Why would honda use a tough as hell steel banjo bolt for the return line which has little pressure? (it took quite a bit for us to cut through the metal. It was also partially rusted, but was still tough.

ii)It started leaking more after I pushed the car. It was a short sprint to 80km/h, but my shift points were pretty high.

Reasons why it is the return line:
i)When the ignition is on (but the motor is not running), there is no leak. Only when the motor is running does it start to leak out. It leaks out, but doesn't spray. The fuel pump is activated as soon as the car is in ignition, not when the motor is on. Therefore, if it was the pressure line, it should leak as soon as the fuel pump pressurizes the hoses.

ii)I noticed no decrease in performance when it was leaking. If it was the pressure line, there should be a decrease in throttle response due to fuel starvation.

Also, when it was leaking, and the fuel cap was open (after 10-15min of driving) that familiar "WHOOSH!" sound was absent. Finally, the leak would stop eventually if the car was turned off and just left alone. Thanks for your help and I apologize if I posted in the wrong forum.

bbarbulo

iTrader: (2)

Interesting....some good observations, but since I don't have a 4th gen, I couldn't tell you. But why not follow this line to the engine compartment, and if it has a filter in it down the line, it's a pressure line, but if it comes off the fuel rail after the pressure regulator, then it's a return line. Also, the size of it would indicate one way or another, if it's the thinner of two lines, it's a return line. Either way, if you replaced it with a high pressure fuel resitant rubber section, it should be sufficient for your needs.