Fuel spills fuelling up, tank leaks when full

[Highway 89]

My RT3, is impossible to fill up as it leaks when full, also burps fuel everywhere. If I go to ali tank can the breather system be revised somehow to alleviate the blow back issue or has that been addressed already with later ali tanks?? I now have my car registered in Australia and loving it but fuel issues are very limiting, with the leaks ,the fueling up and the crazy sender unit readings I can only safely do short runs. I would like to invest in a new ali tank, a better
fuel pump as mine has a broken / glued pull line attachment and the holley easy level sender unit but only if it's going to alleviate these problems. Any advice appreciated

[xb-60]

Are you able to post a picture of your breather system?

Cheers,
Glen

[Highway 89]

Short answer, no, 3/8 I'd fuel line outlet on the side of the tank close as possible to the top leading to 7/10 up the filler tube, 6 in from filler cap

[xb-60]

Highway 89,
Not sure what this means...

Originally Posted by Highway 89

... 7/10 up the filler tube...

The system needs to be able to breathe and burb adequately, but you already know that of course.
Here's a picture of my breather system. That might help, possibly...



Good luck with it,
Glen

[fomocojo]

I have a Classiccs Roadster that has been exhibiting the same problems ever since I bought it.I have to fill at half pressure on the nozzle or it blows right up and out.It takes a long time to fill and I have to watch carefully until I see bubbles then quickly shut off or it overflows.The last fill up I got it right only to see a large puddle of fuel on the ground.I talked to my mechanic and he is pretty sure it is a breather issue and he says he can fix it.I have to run the tank down to near empty then I will take it in.I will pass on all information after the repair and maybe it will help you.

[Highway 89]

Thanks Glenn , your setup appears to be a top loading situation as on the bdr fuel enters on the side of the tank, and you have 2 breather lines , looks like a very nice setup you have there , thanks for your help. Jo I'd like to see what your mechanic comes up with as well, I will try to upload a pic of my setup

[C5GTO]

I was having an issue with fuel being pushed up the filler pipe and leaking while driving my Classic Roadster Cobra. The issue and how to fabricate a good venting system is in this thread: Gas tank becoming pressurized???

[Quentin Z]

Check out this thread; last post particularly:

Gas Smell

Who knows, might help. Also, I've read to only fuel up with the nozzle parallel to the fender, handle towards the rear of the car. I do this every time and never have a problem.

[Highway 89]

Thanks for the heads up there, I read trough all those comments and scenarios, it's quite complex how it all works, I will need reread and get my head around all that , with so many bdr's on the forum and same tanks / issues i was hoping there would be a very simple easy fix and a simple pic or 2 would send me in the right direction. There is no valves or such on my system just a small fuel line from near the top of the tank which joins into the filler neck 3/4 way up.If this is safe and acceptable by engineering standards I will put up with the slow fuelling up and get a new ali tank, pump and sender unit. I'm still hoping to improve the system if I can, I'll keep reading and googling ad the tank etc will no doubt take some time to arrive here in Australia, thanks so much for your contributions.

[sunman]

EFI systems are sealed with lite pressure and a sealing gas cap.

The line from fitting at top of filler neck is a “fuel drainback line” not a vent.

Gas caps are vented, carb or sealed, EFI for street rides usually.

Why is your fuel not draining back to fitting on top of tank?

[Highway 89]

There are 2 issues with mine atm, 1 is the fuel blowback spill on filling up which I thought was something to do with venting and I thought that drainback line was the vent. The other problem I have is when I fill right up she leaks fuel from on top the tank where pump and sender unit fit, but I'm guessing that's just a bad gasket or so, although I had to drain about 4 gallons to get the leak to stop.

[sunman]

I don’t feel comfortable with the filler neck and use fuel cell in the trunk.
On this Classic Roadsters I can put sideways mounted mufflers where the tank was and use the valance panel mounted C4 Corvette exhaust bezels.
EFI sealed system no vent no gas smell

[Highway 89]

Hey sunman that looks like a sweet setup

[bobcowan]

I have an alum tank. When filling, I set the nozzle all the way and lock the filler at the slowest rate. It gets full w/o belching anything up. The fuel vent or drain back hose allows easy filling.

For leak, the first thing I'd check is the filler hose clamp at the tank. If the clamps are already tight, pull the filler hose off, and inspect the sealing surface. Maybe there's some casting flash or debris preventing a complete seal.

The fuel sender on my car was pretty bad. No matter how I adjusted it, it would never work well. I replaced with a Holley universal sending unit, and now it works well.
Fuel Level Sender

[Highway 89]

Thanks Bob , I will get the same sender as you have with the new tank and pump, see how that goes, as I understand there's nothing fundamentally wrong with the bdr setup.

[sunman]

Pull the line from the neck fitting, add a 3’ piece of tubing with a short piece of pipe and blow. Simple line check.

My sender flange has a top of tank fitting and a fuel return to a baffled well in bottom of tank fitting. I EFI modified my CR steel tank (future thread).
Check that the filler neck line does run to a top of tank fitting.

When you blow with the cap on and neck fitting plugged the EFI fuel system should be sealed when the new tank is installed.

There is a bung on the filler connection side of BDR aluminum tank, but it looks to low to be a top of tank fitting.
I’m not familiar with BDR tank, is that bung a bottom of tank fuel return from regulator line fitting?

[Highway 89]

I guess the aluminium tank is same as bdr plastic tank so I guess it's a drainback line, i havent seen tha actual ali tanks

[sunman]

The man at Iconic just said the bung is a filler neck drainback/vent line and they have a carb tank and a different EFI tank.
The gas tank has been in engineering for improvements.

Dude seemed unsure, check for yourself if bung has a line to bottom of tank as a EFI fuel return would be.
It possibly is a fuel return and he doesn’t know it.

My top of tank vent fitting was on the sender flange on top of tank.
Like the one on my 86 Mustang tank.

I copy/steal designs, Robert Haugen, owns the Sebring/Saxon CR moulds, has the C4 exhaust bezels on his Sebring. It’s clean no pipe hanging down.

[Highway 89]

That's really interesting, very appreciated info, I didn't understand there is different tanks setups for fuel injection and carburettor, first fuel injection car I've owned and not much experience working on cars , I have restored 3 Italian motorcycles. I will contact bdr in SA and see if they can shed any light as well. Australia is a bit restrictive when it comes to sourcing parts and info on such things, especially West Australia.

[sunman]

This is a 86 Mustang EFI and the sender flange top of tank vent now connects to the purge valve and canister that’s controlled by the ECM.
Vents into intake for emissions control. Good for street cars.
Vent to atmosphere you smell gas and OBD2 throws codes.

My CR sealed cap filler neck drain line ran to another second fitting on top of tank. Didn’t use it tho now it’s a flush fuel cell cap.

I’ve driven Ford trucks with 302/5.0 for 40 years.
They usually limp home and a scanner tells you what’s wrong.
EEC IV system ECM fix is replace capacitors in power supply.

My 2007 Sport Trac 4.6 3V has 240K miles no problems.
The timing chain guides are plastic, changed at 200k miles.