Clogged fuel tank vent

[TR87386]

OK guys I think I am kind of screwed on this one but I figured I would consult the guru's here. I had a gas tank develope a tiny hole in the bottom of the tank. The car was being stored under cover but outside for about 4 years. When I started getting the car back up and running the tank/fuel pump were replaced. But since the new tank went in I have this weird pressure build up in the tank when I remove the gas cap. I finaly figured out what was up. The vent line that goes to the carcole canister is completely blocked with corosion. I removed the tank and got the 18-20 inch peice of metal vent line cleared that sits directly over the tank but the hard line that runs from just above the axle to the engine bay is blocked also. I used a piece of wire to snake through the small line and compressed air to blow it out but this is not going to work for the long run. I was hoping that someone knew of a miracle rust dissolver that I could work into this line and maybe clear the blockage. Looks like there are products out there but most are for removing rust from areas that you can get at and sand/prep etc. Thanks -Patrick

 

[scot w.]

OK guys I think I am kind of screwed on this one but I figured I would consult the guru's here. I had a gas tank develope a tiny hole in the bottom of the tank. The car was being stored under cover but outside for about 4 years. When I started getting the car back up and running the tank/fuel pump were replaced. But since the new tank went in I have this weird pressure build up in the tank when I remove the gas cap. I finaly figured out what was up. The vent line that goes to the carcole canister is completely blocked with corosion. I removed the tank and got the 18-20 inch peice of metal vent line cleared that sits directly over the tank but the hard line that runs from just above the axle to the engine bay is blocked also. I used a piece of wire to snake through the small line and compressed air to blow it out but this is not going to work for the long run. I was hoping that someone knew of a miracle rust dissolver that I could work into this line and maybe clear the blockage. Looks like there are products out there but most are for removing rust from areas that you can get at and sand/prep etc. Thanks -Patrick

Patrick I had the exact same problem with my tank creating back preasure, So much back preasure that it would almost blow the cap in my chest! I would make the car die too.

I dropped my tank and realized that my vent line was clogged real bad, Instead of clearing the whole stock vent line I just took some foam and made my own filter right at the vent tube on top of the fuel pump hanger.

1) with the tank dropped I simply removed the rubber vent tube on the top of the tank.

2) Take some foam and cut a small square and put a hole in the center of the foam and simply slide it over the metal vent tube coming out of the pump hanger and your done!

This can also be done using some rubber hose and a clamp on filter at the end of it.

Scot W.

 

[TR87386]

Scott, thanks for the reply, I was thinking that if there was no way I could get this unclogged I would try something like that but low and behold a little PB Blaster and 200 psi from my compressor and now I have quite a mess on the garage floor. I had to make up a coupling out of a piece of high pressure hose and 2 small hose clamps, clamped it to the end of the vent in the engine bay and let er rip. Took a few hours but it worked!!! :biggrin:

 

[TR87386]

Quick question Scott, when you said your car was dying did you notice if you were getting any abnormal knock retard? I have been at it with this car for almost 2 years , just had it up the track last week and I am still getting a little KR when I shouldn't (15 lbs boost with 93 octane) I have come a long way but still battling tuning issues. I thought I was good until my track outing. I am almost sure it was pressure in the tank but maybe the noise I was hearing when I cracked the gas cap was a vacume in the tank thus making the fuel pump have to overcome the vacume in the tank while also fueling the motor.

 

[Chuck Leeper]

Nope...

Suggest you not do that "fix". When the tank has hot fuel in it, and it cools off, the vent will supply air, as the volume of air is reduced, due to cooling.. That can/will pull rust and other crap into the tank... Replace the line w/ hose, if you need the cannister...
Or, you could periodically send me your injectors to be cleaned!!

 

[BetMinesFaster]

Patrick I had the exact same problem with my tank creating back preasure, So much back preasure that it would almost blow the cap in my chest! I would make the car die too.

I dropped my tank and realized that my vent line was clogged real bad, Instead of clearing the whole stock vent line I just took some foam and made my own filter right at the vent tube on top of the fuel pump hanger.

1) with the tank dropped I simply removed the rubber vent tube on the top of the tank.

2) Take some foam and cut a small square and put a hole in the center of the foam and simply slide it over the metal vent tube coming out of the pump hanger and your done!

This can also be done using some rubber hose and a clamp on filter at the end of it.

Scot W.

Scot, is there any issues with fuel smell with just the foam on the sender?

 

[JST A 6]

Scot, is there any issues with fuel smell with just the foam on the sender?

I would go with the clamp-on filter. No telling what the fuel/vapors will do to the foam depending on what type of foam you use. It could get eaten away completely, then your tank very well could suck some garbage in as it cools. Not saying I think that's likely since the fuel doesn't cool instantly. Purpose-made fuel filters *usually* have a pleated paper element in them that you know will stand up to this usage.

 

[challengermike]

I wonder if they make vented fuel caps for our cars?I have the same problem.

 

[challengermike]

I just went on a couple of parts stores websites and they do have vented caps for our cars.

 

[scot w.]

To answer some of your questions..

1) NO smell of fumes at all!! (My garage is under my house)

2) The foam I used, I previously soaked a piece completely in gasoline to see what would happen. (Nothing happened)

I will be going with a clamp on filter after I replace my in-tank pump. I went with the foam as a temporary fix to the venting problem.

I have had two vented caps and they still did not work!

I have drilled a small 1/8" hole in the top of my cap, still didn't work!

I hope the vent tube disconnected and foam over it works. If not, I have bigger problems..

Scot W.