Fuel pouring out

[Jon]

I noticed a slight fuel smell while out driving the car a few weeks ago - I'd just filled up so I just put it down to some smells lingering from the petrol station.

However, I turned the car on today and found that fuel was pouring out from under the car behind the seat positions - needless to say I turned it off sharpish!

Clearly it hasn't been leaking like this while the car has been off - since there wouldn't have any left (within minutes let alone weeks) and after turning it off the pouring seems to have stopped again.

Anyone else experienced this? Any ideas on where to start (I'm guessing the fuel pump) and availability of parts?

[CalElan]

More knowledgeable folks will be along shortly.. I believe the fuel pump is in the tank.
When you open the hood stowage area and prop the cover open you'll see there is a black plastic panel that sits inside this area directly behind the fuel filler. It's pretty easy to remove and then you can see a lot of the fuel pipes. I'd be tempted to take the panel out and have a look - The one good thing about pouring out is that it should be easy to spot the problem.

If you can't see from here, take the panel's twin off the other side and remove the Plastic tray that goes the full width over the battery. There's a small access panel which comes off and gives access to the fuel filter.

Hope that helps a little..

[Jon]

Thanks CalElan,

We are currently suffering an utterly miserable afternoon and the rain is pouring down too.

Looks like a nicer day is expected tomorrow so I'll may wait until then before I take a further look...

[CalElan]

Sounds like a plan - good luck with it..

[Jon]

Hmm, have taken off all the carpet and all the panels under the hood stowage lid - I can see the fuel filler pipes and a pump - but I can't see any obvious signs of any fuel leak - there was so much pouring out I would have thought there would be some visible signs even if most of the fuel evaporated.

[dapinky]

Jon,

Whilst you have access to the area, perhaps if you turned on the ignition (but not start the engine) it would give a clue.

As the pump starts it will send fuel to the injector rail, and then return excess to the tank (by way of the return pipe). The whole system is presurised by the pump to allow the injectors to squirt in the right amount of fuel, and the pressure is regulated by a regulator on the end of the fuel rail.

If the leak is on the pipe from the pump to the filter it should be seen instantly you turn the key on (I assume you have removed the rectangular plate to see the filter - if not, it is worth doing).

If the leak is between the filter and the engine, it will be just a moment after you turn the key.

If it is at the engine, the fuel will run out in the engine bay, not the location you describe - so is unlikely.

If it happens after the rail is pressurised it will be on the pipe returning fuel to the top of the tank - so it may be at the tank fitting which you will see, or more likely, somewhere along the pipe.

If the fuel pump turns off after a few seconds (like when you would normally start the car) then it will show that the regulator is stopping the flow at the designated fuel pressure (50-60psi if i remember correctly, but I could be wrong - not that the figures matter too much at the moment!).

I would expect it to be fairly obvious where the fuel comes from when it is under pressure...... as you say, had it been a simple leak then the tank would be empty a while ago, so it suggests that it only happens under pressure from the pump, so is likely to be on the pipework.

The fuel pipes are a heat moulded plastic item and can get squashed and damaged by various means due to their location running the length of the car. it is possible that someone has replaced them at some stage and either used the wrong sort of rubber pipe to do the 'repair' (not a fuel-resistant pipe) or that a joint is not formed properly. Or maybe the original one has split recently.

I would somehow expect that it would be likely to be the 'return' pipe where the problem is, otherwise fuel would syphon out when the 'feed' pipe is full of petrol and you would get an empty tank (but not if the damage is at a high point in the system, so it *could* still be a feed pipe issue.

If the fuel pump does not turn off after a couple of seconds it indicates that there is insufficient pressure in the system for the injectors to run properly (because of the leak!) and if you were to drive the car like that you may run the risk of under-fuelling which could cause the engine to run lean and blow up (not to mention the fire risk from the leaking petrol ) - this is justs an over dramatisation on my part, but just stating the worst case scenario - - in no way am I suggesting that you'd try and drive until you can isolate and cure the leak

[HJ2]

Be safe!

There are known issues with the fuel tank as well. The filler neck tends to crack.
Since the problems started when you filled it up completely, the fuel runs out of the crack in the fillerneck until it is empty. After that it only comes out when you move the car so the fuel sloshes in the crack again.
The leak would be on the filler side, just behind the seat, looking from the outside.

Make sure to check that out as well.

Good luck!

[Jon]

Thanks Dave - the fuel was most certainly coming from under the car under the hood stowage/behind the seat positions, definitely not from anywhere near the engine compartment.

The car is back in the garage now [pushed] and I'm very concerned, given the amount of fuel coming out yesterday, about experimenting whilst in such an enclosed space - so I may wait until I can get some assistance to de-garage and to standby with an extinguisher too.

I certainly wouldn't consider driving it anywhere!

I've removed the square white plate behind the passenger seat - it is mostly full with the top of whatever device is underneath it - but no obvious signs of any issue there.

H2J - this was definitely looked more than sloshing - it was pouring out, the drive way was covered in seconds?

[HJ2]

The device is the fuel filter & top of the pump assembly:-)

From what side did the fuel drip down?

[Jon]

It was pretty central between the drivers and passenger seats - perhaps slightly more towards the passenger side?

[HJ2]

Well, at least you non know where to check.
Good luck!

[Jon]

fuelpump.jpg

whitepanel.jpg

fueltank.jpg

So to my untrained eye, looks like it may be leaking down from the gap to the left of the fuel tank?

Would that be consistent with the cracked fuel filler neck?

Is there anything else I can see/check without getting the car on a lift and removing the tank?

[Brit-Car-Nut]

You need to look at the fuel filter and lines. There is an access hole to the left of the tank (when looking backward from the seat) in the hood stowage compartment.

Filter access.jpg

[Jon]

Thanks Brit-Car-Nut - for some reason I didn't notice that.

fulefilter.jpg

Doesn't look like there is any sign of anything leaking here....


I'd be inclined to wonder if it was a crack around in the fuel filler (as commented in several other threads) but firstly it only occurs when the ignition is on and secondly it seems to be coming from the far side of the tank to the filler nozzle.

[Brit-Car-Nut]

I am assuming that you are able to recreate the leak by turning the ignition on? It will only run the pump for a few seconds, but the leak should be obvious.

You need to make it leak and then turn off the pump and follow the dripping fuel.

The line from the tank to the filter is fragile and it looks like the nylon line at the filter fitting cracked during a previous filter change and they patched it with a rubber hose that is pushed up on the original line clamped to the middle of the nylon tube and pushed on the filter fitting barb at the other end. The original line at the filter was nylon, not rubber fuel line.

[dapinky]

Jon,

Now that you have access to all the bits I mentioned - what happens when you turn on the ignition?

If the leak is apparent, then it'll be somewhere in the pipework (and unions) between the two connections at the top of the tank (to and from the engine via filter, rails etc etc!).

If the pump pressurises the system, but there is no leak, then it indicates a split in the tank (probably the under-the-filler-neck weak point).

If it pressurises and leaks but you can't see the leak from the pipework, it is possible that the tank is holed in an area which receives a spray from the return hose.

If it is a split in the tank (under the filler neck), then once the fuel level drops to about 2/3 (~20-25 litres) the leak will stop.

Unfortunately, the only way to repair the issue is to replace the tank with a good one, or repair the split with proper hot-air welding - both of which require removal of the tank, which is best done on a ramp due to the vast amount of clearance required to drop the tank out vertically (RNS suspension needs removing). It is possible to do with axle stands, but you need to get the car up quite high. The actual repair is straightforward - for someone who has the right tools and knowledge (plenty of 'How To' videos on YouTube). Be aware that it can't be glued as nowt will stick properly to the plastic and remain petrol proof.

It took about half an hour to stitch up my crack ( ) but most of that time was filling the tank up with water to prevent accidental ignition of stray vapours (should be okay with the right tools - hot air soldering iron - as no naked flames are present, but better safe than sorry).

I then re-inforced the repaired area with sikaflex (well, some other polyethelene adhesive, but you know what I mean!) to prevent recurrence.

All in all, half a days work.

Edit to reflect Johns' post......

If the leak is in that line, the whole pipe needs replacing with a proper pipe - rubber is okay AS LONG AS ITS HIGH PRESSURE FUEL HOSE - do it in one piece and use good jubilee clips. Have a look at this page I wrote for the Wiki.

[Jon]

Thanks Brit-Car-Nut and Dave - I think I'm going to hold off the ignition test until I can get the car out in the open.


I assume that some of the 3 pipes I can see in the under car picture are the fuel lines? Using a video camera I've looked up the gap which they go up and they look clean as far up as I can see.


Would I be correct in saying that if the issue was a crack in the fuel tank it would have leaked constantly until the petrol ran below this level (and unlikely to be affected by the pressurisation).

So if it only occurs under pressurisation indicates pipework/joints/connections downstream of the fuel pump?

Or am I being too simplistic?

[dapinky]

Jon, Not simplistic at all - thats exactly what I'd expect (having had both pipework and tank leaks in the past).

[Jon]

The line from the tank to the filter is fragile and it looks like the nylon line at the filter fitting cracked during a previous filter change and they patched it with a rubber hose that is pushed up on the original line clamped to the middle of the nylon tube and pushed on the filter fitting barb at the other end. The original line at the filter was nylon, not rubber fuel line.

Sorry Brit-Car-Nut - didn't fully get this the first time round - but I understand now.

Yes, the connection to the left of the fuel pump has a sort (2 inch-ish) rubber hose which is connected with a jubilee clip to a much narrower gauge hose (which I guess is the original nylon hose which you are saying would originally have been connected directly to the left side of the fuel filter).

However, there doesn't appear to be any indication of any leak anywhere around these hoses or connectors - there is a lot of residual dry dusty type dirt which I wouldn't expect if there was any sort of fluid running out recently?

Thanks again to everyone for the help and clarifications - if I feel brave or crazy I may try testing the ignition position in the next couple of days and see if I can get any further!

I certainly understand quite a bit more about the Elan fuel system than I did yesterday (when I knew you spent cash out, put petrol in and went forwards...).

[Jon]

OK, I'm even more confused than ever!

I decided give it ago setting ignition to ready to see if that triggered the leak - nothing, started the car still nothing...absolutely no fuel leak at all??

A very stark contrast to two days ago and yet I can't see what has changed...

The fuel gauge is currently showing as 2/3rd full - which would be consistent with the "cracked neck" syndrome - but it is also consistent with my last fill of the tank, the subsequent drive and the fuel loss on Wednesday.

The "cracked neck" doesn't seem to be consistent with having filled up 6 weeks ago - left the car standing/garaged since, no sign (or smell of any leak) and sudden significant loss of fuel on ignition.


So perhaps some random and idiotic questions:

i) Is there any way that the "cracked neck" would retain the fuel and only leak upon pressurisation of the system (until the level is below the crack then even pressurisation doesn't matter)?

ii) Is there anywhere/think which could collect a slow leak of fuel over the 6 standing weeks from somewhere (like a reservoir) which then under pressurisation causes that to rapidly leak out?


I'm really grasping at straws here as I'm struggling to make any sense of what is happening!