How Severe is This...

[josh2109]

Hi folks,

I decided to have a look inside my fuel tank the other night, and this is what I found:




As you can see there are a few flecks of rust, and my tank is corroding slightly. I've had cutting out issues previously, but a new inline fuel filter and a change of carb seems to have sent that problem away for a bit.

But back to my original question, how severe is the problem I've got from the amount of rust in the tank? I have a 3 series filler neck and inline filters are cheap, am I likely to be able to keep on top of the problem just through a new neck and filtration, or is that enough sediment to warrant cleaning the tank out. In all honesty I don't fancy the hassle of dropping the tank After seeing that the in tank pick up doesn't have a filter, I've wondered if I couldn't trap a lot of the rust by using a larger fuel filter and swapping it out regularly...

Cheers,
Josh

[the edmundator]

If your tank has corroded inside, I guess it's been stored for a long time without any fuel in the tank. Otherwise it's very unusual for the inside of the tank to corrode in a car that's regularly used (unless it's coming through from the outside, in which case it's totally f***ed).

I would expect that the larger pieces of rust are coming from the filler neck rather than the tank. A magnet on a wire will help you pick up most of the rust if you really don't want to remove the tank.

To be honest, if you've got rust inside the tank, it really needs replacing. They aren't all that expensive - I think I paid about £60 a couple of years ago. The filler-neck is probably going to be more expensive, but you should definitely replace that.

[josh2109]

It's a shame nobody makes a plastic tank really. But yeah I had come to the conclusion the filler neck was goosed. Can't say I want to replace the tank though :( I've had a scramble around underneath and it's ok on the outside, and from poking my head in the tank I'm confident the corrosion is internal. I'll probably just leave it until it's more severe, I drive another car as my daily.

My main concern is cutting out when I do use it. I was just curios to know if that was a large number of rust flakes for these cars, or if the typical fubar filler neck made a lot more mess... I may just have to go for a long drive to find out myself

I'll get the filler neck sorted at least, I'm hoping to make a start tomorrow night. I got a 3 series filler neck from the scrappy so with a bit of heat I should be able to get it in.

[Nate]

You will get rust in the tank that comes from the large tanks in petrol stations too.

what I did to sort the problem was dump a large magnet inside the tank and away from the fuel pickup. This will attract most of the bits. I then punched a large hole in the end of the strainer on the end of the pickup pipe (removing it altogether makes the pipe slightly shorter) so that any rusty bits that did get sucked up wouldn't just block the pickup. I then fitted a large filter underneat the car as close to the tank as I could, and a second one in the engine bay. They were the larger size filter. Bulk buy and get them cheap. I got them from the autojumble at rufforth, and a pack of 10 was only a few quid. I then changed them every time I changed the oil (every 5k ish)

don't forget that there is also a filter built into the weber carb - undo the 17mm nut directly under the inlet to the carb, remove the filter and wash it out with carb cleaner. If you get white furry stuff in this filter, you've probably got water getting into the fuel, most likely they the filler neck. Cure the leak, then add some wynns "dry fuel" when you fill up. It absorbs the water, letting it get harmlessly burnt off.

[josh2109]

Cheers Nate, I have to say I was considering sticking a neodymium (sp. ) magnet in the tank near the filler neck, kind of the same principle as the magnetic sump plugs that I've seen a few Prelude owners using. It sounds like it might be a plan. As for the pick up, I was surprised to find that mine has no strainer Somebody must have removed it previously I guess. As for fuel filters, I think I have some in my stash of Golf bits, I'll have a look online to see if I get get anything larger though. I have some spare fuel hose, so I may try mounting the filter vertically with the fuel entering at the top. Hopefully then gravity will prevent any large debris heading back to the tank when I kill the ignition, and I can swap the filter out to remove the rust flakes that miss the magnet.

Another thought I had was putting a large cube of the foam they use in racing fuel cells below the in tank pick up, I was wondering if the large surface area might prevent the rust clogging it whilst the car is running.

As for the carb, I put a Pierburg on my Scirocco when I replaced the old manual choke one I need to inspect the float bowl at some point though, it's on the never ending 'to do' list I have.

I heard that the ethanol in fuel these days can also cause problems in carby cars due to moisture by the way? I don't know if it helps but I always fill up with super unleaded from Shell and BP

[the edmundator]

The "old manual choke" carb was probably a newer Weber, which tend to be fitted because no-one understands how to maintain the Pierburg properly any more.

[josh2109]

It was a manual choke converted Pierburg, and I couldn't get along with it I much prefer the autochoke :)

[Nate]

The manual choke conversion often involved swapping bits from similar age astras. The carbs were a 2e2 and 2e3. Its a very easy swap. They're getting a bit thin in the scrappy now though

[josh2109]

I have the invoice for its installation somewhere, so I'm guessing it was a kit. It was installed by a previous owner, presumably to sort out running problems. I found it too fiddly though, so put a carb together from some spares. Seems to work ok now, although my initial fast idle has disappeared recently!

Out of interest, is the pierburg manual choke set up worth anything?? It's not going back on either of my VW's so I might as well de-clutter. Only thing it needs is a new cable as I chopped the nipple off the end of mine to remove it quicker

[james butler]

i didnt know there was a filter inside the pierburgs?
has anyone got a picture please, as mine has been suffering for a while on fueling issues

[josh2109]

Hi mate, I read Nate's post as saying it was Weber's with an internal filter :)

[james butler]

ahh
sorry
i should have gone to specsavers

[james butler]

i didnt know there was a filter inside the pierburgs?
has anyone got a picture please, as mine has been suffering for a while on fueling issues

cant believe i said that!
has any body got a pic of the weber filter location

[Nate]

Not got a pic, but very easy to find. I'd you look at the sticky out bit on the side of the carb where the fuel pipe joins it, there is a 17mm nut on the underside. Unscrew (careful not to loose the sealing washer) and the filter drops out. Be prepared for a small loss of fuel.

[james butler]

Ah cool will try that cheers.