Losing fuel

Hi all,

I was hoping someone might be able to help me with a fuel problem. This has been going on for some time now and I can't seem to figure it out.

Car: Defender 110 CSW 300Tdi (1995)

Problem: fuel leaking from filler cap.

Solutions tried:

• replaced fuel cap twice
• replaced filler neck, breather hose and hose to tank
• replaced injector pump diaphragm

My last resort is going to be to try and fit a different sort of filler cap. Currently I have a vented cap (previous ones tried were also vented) and was wondering if it should be non-vented. Does anyone know how to find whether a vented or non-vented cap should be fitted?

Any suggestions on how to solve this problem will be greatly appreciated.

Thanks very much,
Dan

the next thing I would try would be fuel lift pump, it'll only cost around £25, see if sorts it as it sounds like a pressure problem..

I wouldn't try a non-vented - if there is a pressure build up in yer tank it could only to to force it's way out another way.

Also, you might want to try keep you tank no more than half full, this should give more room for and you should lose less fuel..might make a difference.

I can't help with the answer to your problem, however what I can tell you is that repalcing fuel caps is a waste of your money.
I know because I went down the same path as you when it happened to me with my tdi 200 90.
Unless you wan't to spend money sorting it (and I didn't) just don't fill more than 2/3 full. I know it can be a pain,but it saves alot of diesel.

Thanks Wozy and Hext for your replies.

Up until now we have been running the car at half to two-thirds to conserve fuel as you suggested, however, we are now prepping our car for overland trips to South Africa and Australia so we will need to fill our tank to cover the mileage between stops.

Hext, thanks for the suggestion of the lift pump, but I forgot to include that I have already changed this on the original post. There is not much I haven't changed in the fuel system, only the fuel tank, injector pump (complete) and fuel piping left to change.

Any other ideas on what this could be? And is there any way to test whether you have a fuel pressure problem or not?

Thanks again for your help!

What about fitting a secondry vent to te fuel tank, that exits (for example) to the roof, and then get a non vented cap?

Unless your intending to roll it over that should stop it

Do you get a woosh of pressure when you remove the fuel cap?

If the fuel cap sealing properly - is the fillier housing bent at all?

Thanks jamescronin for your ideas,

It would seem that the additional/secondary vent option may be our only option.

When the filler cap is opened there is no whoosh of pressure, and the filler neck/housing doesn't seem to be bent in anyway.

Any ideas on how to approach a secondary vent option??

Thanks again for your help!

globalnomads said:

Any ideas on how to approach a secondary vent option??

Click to expand...

Depends what you want to do with the landy - if your going wading then the higher the better. If your going driving sideways along steep slopes then it neads to be in the center of the landy (to minimise spillage)

You can dedicated vents for this - check out marine web sites for diesel vents. Should also be able to get an easily fitable tank connector from there as well (and they won't corrode as well - as the vents will be stainless steel and the tank connector whould be brass) - then get a bit of hoze and a sealed filler cap and jobs done (well apart from fitting it)

Thanks for all your info, looks like we are going to have to work out what type of driving we will be undertaking the most and position it accordingly.

Your help is greatly appreciated, thanks again.

Hi all,

I have brought in an old thread with some new problems, hopefully someone out there may know how to put our fuel issues to rest (quotes from previous responses are below).

Well this fuel issue has been a nagging problem for quite a while, and it would seem that finally the problem with the leak is now fixed.

How did it happen....well we had the Landy sprayed and the missus didn't like the look of the crappy diesel soaked filler cap so we forked out for yet another one (third in total) and hey presto the leak went away. When taking a closer look at the two caps side by side, the sealing rubber on the faulty one appeared to be pushed further into the cap, therefore not creating an effective seal. Although this was a brand new filler cap, as was the one previously.....it just appears that we were unlucky in the line of faulty products. Oh well lesson learned!

However......we now have new issues!!!

After all the time chasing what I thought was a pressure build-up problem we now have a vaccum being created. On recent visits to fill up I have noticed a vaccum effect when removing the filler cap as aposed to a pressure release outwards. And on top of this the fuel gauge will now only read as high as 3/4 when completely full (three clicks at the pump) and when reading empty it only takes about 60-65 litres to fill giving a discrepency of about 20 litres or so??

Does anyone have any ideas about what maybe happening here??

Any info will be greatly appreciated.

Regards,

Dan.

globalnomads said:

Hi all,

I was hoping someone might be able to help me with a fuel problem. This has been going on for some time now and I can't seem to figure it out.

Car: Defender 110 CSW 300Tdi (1995)

Problem: fuel leaking from filler cap.



Solutions tried:

• replaced fuel cap twice
• replaced filler neck, breather hose and hose to tank
• replaced injector pump diaphragm

My last resort is going to be to try and fit a different sort of filler cap. Currently I have a vented cap (previous ones tried were also vented) and was wondering if it should be non-vented. Does anyone know how to find whether a vented or non-vented cap should be fitted?

Any suggestions on how to solve this problem will be greatly appreciated.

Thanks very much,
Dan

Click to expand...

hext said:

the next thing I would try would be fuel lift pump, it'll only cost around £25, see if sorts it as it sounds like a pressure problem..

I wouldn't try a non-vented - if there is a pressure build up in yer tank it could only to to force it's way out another way.

Also, you might want to try keep you tank no more than half full, this should give more room for and you should lose less fuel..might make a difference.

Click to expand...

Wozy said:

I can't help with the answer to your problem, however what I can tell you is that repalcing fuel caps is a waste of your money.
I know because I went down the same path as you when it happened to me with my tdi 200 90.
Unless you wan't to spend money sorting it (and I didn't) just don't fill more than 2/3 full. I know it can be a pain,but it saves alot of diesel.

Click to expand...

jamescronin said:

What about fitting a secondry vent to te fuel tank, that exits (for example) to the roof, and then get a non vented cap?

Unless your intending to roll it over that should stop it

Do you get a woosh of pressure when you remove the fuel cap?

If the fuel cap sealing properly - is the fillier housing bent at all?

Click to expand...

jamescronin said:

Depends what you want to do with the landy - if your going wading then the higher the better. If your going driving sideways along steep slopes then it neads to be in the center of the landy (to minimise spillage)

You can dedicated vents for this - check out marine web sites for diesel vents. Should also be able to get an easily fitable tank connector from there as well (and they won't corrode as well - as the vents will be stainless steel and the tank connector whould be brass) - then get a bit of hoze and a sealed filler cap and jobs done (well apart from fitting it)

Click to expand...