Fuel Overflow Problem - Any Suggestion???

[joshcris]

Hi All,

Been having a strange fuel overflow issue with the 86.

Basically I fill her up like usual, drive her home and a couple of hours later I find a puddle of fuel on the ground.. Upon closer inspection the fuel is actually coming out of the fuel tank opening while the fuel cap is still locked in place. I removed the fuel cap while it was leaking and fuel gushed out (nothing crazy) and the fuel neck was full to the brim. Had to siphon out a good 500ml to get the fuel level down to the point where I couldn't see it. The car runs pretty well so, fuel supply isn't an issue. The 4AGE conversion was done in Feb and this overflow problem has come up 3 times.

Just a little worried I'll blow myself up while driving her, and its also a bitch getting that fuel smell out of the cabin.

Could it be pressure build up in the tank caused by something dodgy in the fuel system, or a crapy seal on the standard ADM fuel cap, it does wobble a little when its in the locked position. Could I be overfilling the tank, only ever get to one click at the bosser and I stop (only use 98RON). Driving me nuts trying to figure it out...

Does anybody out there have any idea what could be causing the problem?????

Bit of background on the car:
> Engine converted to JDM 4AGE (Blue & Blacktop)
> Inline fuel pump still using ADM lines with EFI hoses (fuel system conversion done by Toyospares in VIC)
> No unleaded filler adapter fitted (was told it was fine as is and should pass Engineering)

Any input would be appreciated

Cheers

Josh

[rthy]

just a hunch but try unplugging your charcol canister and see if it still does it

[slide86]

to much vapour pressure build up in the tank causing the seal to leak?

maybe the vapour line on the tank is blocked, preventing the pressure from being released

[rthy]

my thinking exactly, the vapor line goes to the charcoal canister you see

[Bobomacho]

i agree with sam, newer cars have pressure release valves on thier fuel caps. mine has rust

[riceburner]

on a side note, my car contiunes to 'hum' which comes out of the fuel cap, as the pressure from the fuel system creates
some sort of vacuum and it hums away for a good 30 sec after the car is turned off... suggestions?

[DRFTR86]

i have this same problem, my boss at work has had a look and pointed the fact that a charcoal/carbon canister not being connected is causing the pressure in the tank to not be releived, causing it to build up and come out of my fuel cap, which was fucked, replaced fuel cap and it hasnt done it since, i gess its still building up a shit load of pressure but it only seems to happen to me on a hot day after ive filled up

[joshcris]

Thanks for the info guys. Did a bit more research today regarding the issue...and most likely it is a vapor line blockage causing the pressure build up in the tank. My shitty fuel cap seal just adds to the problem I see...

Just wondering how I would check for blockage in the main line from the fuel tank to the Carbon Canister and also how I would get rid of any blockages..has anybody done something like this before??? Gonna check the Carbon Canister as well to see if it has shat itself.

Don't really want to dispose of the carbon canister just in case I get probed by the EPA, and also because I still need to engineer the car...

Thanks again for the input, much appreciated :2thumbs:

[joshcris]

<div class='quotetop'>QUOTE (drftr86 @ Mar 26 2008, 10:54 PM) </div>Hey just wondering what fuel cap you replaced it with, can you buy after market fuel caps that are direct replacements for standard ADM items at your local repco or autobarn????

[DRFTR86]

since ur in melb, just ask bursons for a universal fuel cap, plus u get to unlock it with a key, just to add to the many keys you probably have like myself for the 86