VB Fuel tank issue

[c2105026]

Hello all,

I have a stock VB sedan. I have an issue with refuelling.

I understand that my tank has a capacity of 63 L. However, from the time it is bang on empty to 'two clicks full' (with some fuel gushing out) i may be lucky to get 45 L in, at which point the fuel gauge does not read full. What is happening? I have already checked the hoses in the fuel tank area; none are kinked or broken. My theory is that the charcoal canister is full, requiring cleaning out or replacement. Could this be right? Or, could the sender unit be on the fritz?

[VK SL 3800]

Sounds like the sender is out of adjustment or stuffed, red zone should be about 10- 15 litres left in the tank and theres about 1 liter that cant be picked up when you run it bone dry.

It has nothing to do with the carbon canister, all it does is collect fuel vapours and stores them until the carbie purges the canister, giving you the most insignificantly small amount of better fuel economy.

[hiy_po]

It really sounds like your breather hose that hooks up to the top of your tank is not breathing. I read you checked your hoses but they are the classic symptoms.
It is not going to be easy but try disconnect it from just behind the filler cap and suck/blow some air see if it is really working.

[ari666]

your sender is sideways. they twist in and if they are not started in the right spot they sit sideways, so really they go up and down diagonally.

[VK SL 3800]

your sender is sideways. they twist in and if they are not started in the right spot they sit sideways, so really they go up and down diagonally.

Lol, turn right full, turn left empty.

[c2105026]

ok, some things to look at, thanks

[johnmachine]

I agree with hiy_po - sounds like your breather hose.

[Darren_L]

does sound like the main breather hose.
pull the hose off from the filler neck (it's the biggest diameter hose) and try to blow into it.
Should be able to blow into the hose easily, if not it's kinked (usually between the tank and the chassis)

[SL/ENUT]

Its meant to go through the chassis Darren, there is a little gap it fits in.

[Darren_L]

Its meant to go through the chassis Darren, there is a little gap it fits in.

yeah I know, but that's usually where the hose kinks.

[VK SL 3800]

yeah I know, but that's usually where the hose kinks.

Followed by many @#$% #@!% ^%$& until you get the mongrel through, that would have to be the worst part of putting the tank in, feeding that annoying hard as a rock line through that hole.

[Darren_L]

Followed by many @#$% #@!% ^%$& until you get the mongrel through, that would have to be the worst part of putting the tank in, feeding that annoying hard as a rock line through that hole.

yeah it's a pain, but it's getting easier each time I do it lol
I usually put a trolley jack under the tank, put the hose up through the rail and then jack the tank up slowly while gently feeding the hose through. I usually stop part way through and blow through the hose to make sure it hasn't kinked along the way. And then once the tank is in position, I check the hose again.

[VK SL 3800]

I got a dentist mirror last time i did it just to make sure the little bugger hadnt kinked worked pretty well

[vkberlina]

The last time I did my tank I pushed a bar through the hole and bent the boot floor up a little to give better clearence, fitting the EFI tank out of the later model used a larger breather it was too hard to get it through.

Scott

[ari666]

The last time I did my tank I pushed a bar through the hole and bent the boot floor up a little to give better clearence,

same .

[SL/ENUT]

I never did that on the two tanks i've done on two VBs. It fit in there easy and no kinks.

[Darren_L]

I didn't need to bend the floor either, providing you pull the hose through as you lift the tank it won't kink
however 30 years on, and the hose does tend to kink on it's own, so that's probably where the problem is

As said, easiest way to check if it is kinked is to remove the hose from the filler neck end and blow into it (fuel cap off). If you can't blow into it easily, then the hose is blocked/kinked

[vkberlina]

I found my used to kink right where it went through between the rail & boot floor, since opening up the hole the problem was solved.

Scott

[Jonno]

Yeah mine does jt too, I just ignore it

[jpetrou]

It sounds like it's the breather hose that runs from the top middle of the tank to the filler pipe. It is a mongrel to get it in, because it runs through a support rail under the boot floor. Often it gets caught or kinked in the support rail.

Usually this would happen if the fuel tank has been taken out. You cant see this hose, because it runs under the boot floor.

You will need to drop the fuel tank down and check this hose. Once you have the tank off the car, it would pay to replace this hose with a new one.

Once you are ready to install the tank, fit one end of the hose to the middle of the tank top (do not cut it to length yet - leave some extra). You will need a second or third person to feed the hose through the rail and guide it through this rail while you are lifting the tank up.

Then once the tank is bolted in, you can cut the breather hose to the correct length and connect it to the filler neck.

With a some help and patience you can get right. Good luck.