Are there any problems with not running a fuel tank breather line to carbon canister?

[WHITCHY]

My return line on my AE86 is blocked, and it doesn't seem like the block will budge, so I have a been thinking about running the fuel return along the current breather line, and just having the breather just a short piece of hose coming from the line on the tank not hooked up to anything.
Will this cause any problems/dangers?

I just really don't want to have to run a new return line, as I had enough trouble removing one from another Sprinter,and I imagine it would be about 100 times harder and time consuming to remove mine and then install a new one! as the line runs really close to the gear box and tailshaft and the easiest way to do it would be by dropping the box and tail shaft and I dont really have the time!

Thanks for any info.
Cheers.
-Whitchy-

[o_man_ra23]

Early TA22's had a breather similar to the one you want to put in. It simply was a hose which went out of the top of the tank(tank behind seat), down and vented through a valve of some sort into the subframe rail. So, find out what sort of valve that was, and i would strongly suggest using one.

Cheers, Owen

[YLD-16L]

So let me get this clear.

Your fuel line is fine.

Your return line is well and truly blocked (kinked or crushed line perhaps?)

You wish to use the line that runs to the carbon cannister as your return line.

The problem will be that the short line you plan to run as a breather will:

Leak petrol from it when you have a full tank, especially on hot days when the fuel expands (i.e. you fill car, park it in hot car park, return to find fuel poured out your "breather" line and some bogans durry lit up the spilt fuel farken booommmwhooooshh!!!!!!111kaaaa)

The smell of fuel may be annoying to you or your passengers.

It will not meet EPA requirements should you ever get pulled up and inspected.

Some old cars (like mine) vent to atmosphere from the tank but the line comes from the tank up to the top of the roof line, passes through a series of passages (to prevent fuel from escaping and only allowing vapour to escape) and then vent at the rear of the car.

In summary, it would be best if you did the job properly and found the cause of the blockage in your return line and rectified it.

[The Witzl]

Witchy,

I've often used the breather line as the fuel return line on AE86 and AE71 cars when going EFI, since the breather is a larger pipe - so there is no problems with using the actual line.

However, you really should have your breather line going through your charcaol canister. I'll update my FAQ soon to include an explanation of the charcoal can system...... basically the fuel vapours are filtered out and drawn out by the vacuum line to the manifold, and excess tank pressures released by the small rubber hose that goes into the chassis rail from the bottom of the charcaol can


as for the blocked line..... compressed air is your friend!

[Nim]

A friend of a friend had a problem with their fuel breather line, I think it was in a '88 Honda Prelude. It was split and leaking into the cabin. This person is a smoker. The mechanic said she was lucky it didn't ignite and explode. So there's something to think about.

[Draven]

You could always do it the cheap way, and just run some rubber EFI tubing all the way beside your current return line and use that. just make sure you have eleventy billion cable ties.

[o_man_ra23]

running the flexy line will work, ive done it before, but its actually not legal But thats not a worry if you dont have to pass it through any sort of roadworthy(here in qld, you only need a rwc to get the car registered, you dont need it every year).

Cheers, Owen

[BabyZ]

I would have thought the flex line would have been a simple answer, and certainly better than a dodgy vent.

I'm glad no-one told the engineer that passed my EFI Hilux about this "illegality" - the whole fuel feed is flex hose!! Although the return line is solid.

Maybe if the blockage is a kink or damage that can be located, you can cut it out and replace that section with a little bit of flexi EFI hose.

Make sure it is proper EFI hose though, regular rubber hose won't cut it.

[o_man_ra23]

return line should be low pressure, and as such you dont need proper efi hose. If you do need proper efi hose though, the ends where the fixed line was cut will need to be bulged, or the hose clamp wont hold up.

Cheers, Owen

[Draven]

it's not illegal in nsw, as long as the ends are properly clamped and it's properly fixed to the body

[BabyZ]

the ends where the fixed line was cut will need to be bulged, or the hose clamp wont hold up.

In theory, yes. In practice, mine haven't leaked yet. I am only running a standard pressure EFI fuel pump, but I would assume Whitchy has the same.

Cheers,
Adam.

[fade-e]

with the TA22's, the breather is at the highest point of the fuel tank, it is literally just a hose with a tiny carby filter like thing (dont know what the name is) and then more hose that goes into the boot floor, which is vented to atmos under the car.

also from the tank, the pipe that comes out, goes up bout 10mm and then to the right bout 100mm (maybe less)... its like an L on its face (if that makes sense)

can take a pic if you like and post it up since my tank is out of the car ATM

cheers

[gianttomato]

I'd be trying to unblock your return line.

An idea might be to identify where in the pipe the blockage is. Use some narrow gauge wire and pass it down the return line. When it stops, you know where your blockage is. Take note of how far into the return line the wire has passed. Pull out the wire, run it beside your return line and mark. To confirm, pass it down the other end and do the same. It should come to roughly the same spot. Cut the return line and check for blockages either side of the cut. Unblock with a stiff piece of wire (coat hangers work a treat) and flush the grunge out with some turps or petrol. Fit a piece of fuel line to patch it up - regular stuff will be fine.

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