'88 Scala, rusty filler neck - lumpy idle - what next?

[frlrubett]

Annoyingly my mate picked up my Scala for me and on the list was to check the fuel filler neck. He did check but didn't look up to the top with a light to see the small hole which was there.

Had lumpy running and was checking through the usual causes and found the neck issue today, its small-ish about 5p size with a hole on the roof of pipe. I already have a spare neck and will get this changed and the magnet in the fuel tank trick going on to get rid of the rust. Already had the fuel filter done but will keep and eye on all of it. Going to treat any rust which is around that area and fingers crossed all will be good.

Question is... what else can I do? Keep changing filters to clean the system or will I have to do some remedial work with the fuel lines?

Thanks!

[james butler]

keep changing the fuel filters and like you say pop a magnet inside the tank and fish out as much rust as possible then leave a magnet in the tank as far away from the pick up pipe as possible.
you can blow the fuel lines through with an air line to remove built up sludge by taking the pipes off the tank one at a time and put them in a jar then at the engine end take the fuel feed off and blow through with an airline.
is it carb or injection?

[frlrubett]

keep changing the fuel filters and like you say pop a magnet inside the tank and fish out as much rust as possible then leave a magnet in the tank as far away from the pick up pipe as possible.
you can blow the fuel lines through with an air line to remove built up sludge by taking the pipes off the tank one at a time and put them in a jar then at the engine end take the fuel feed off and blow through with an airline.
is it carb or injection?

injection.

The pipe which connects the neck to the tank, whats the diameter of that? mine looks like it will perish when I remove it.

[mark1gls]

Check the length of yours to make sure this fits.
https://www.ebay.co.uk/itm/VW-GOLF-MK1- ... SwD0lUkVOy

Buy 2 new jubilee clips as best to change them as well. I’ve always replaced the rubber hose each time I’ve changed the filler neck as the old ones go hard and they are a nightmare to fit on a new pipe.

When in the fuel tank check the lift pump has the filter attached to the end as they can easily drop off when removing the pump and sender, the filter will help stop some of the bits getting into the fuel system.

Lift pump filter looks like this.
https://www.ebay.co.uk/itm/VW-GOLF-MK1- ... SwMzVTw6~7

I’ve the original fuel tank in my Mk1 golf and it’s a little rusty inside, I’ve left a magnet in there and I change my main fuel filter (in engine bay) every 20,000 miles or 2 years

[frlrubett]

Thanks for that,

Is there anything else to get the idle back to normal - assuming it is the filler neck causing it? Does the hole in the neck lower the pressure and a new part will solve that? Or is it just a case of running a load of rust free fuel through it.

[mark1gls]

I guess the car is new to you so has it ever run right before?

I would start by replacing the servicing items, spark plugs, HT leads, Dissy cap, Rotor arm, Air filter and fuel filter.

What is the idle speed, try increasing the idle speed, 950-1000 rpm (I find mine runs smoother at 1000 rpm)

What type of fuel are you using, Super unleaded or normal unleaded and did the previous owner say what fuel the car is set up to run on as the timing is different..

Is it always lumpy at idle or better when cold or hot?

Pull out the fuel injectors and check spray pattern, measure the fuel out put and see if they drip when shut off.

Pressure test the fuel system.

Any more info and what you have done so far would help answer.

The K-jet system is very reliable when working but it does not like water and rusty bits etc getting into it and can be expensive to fix as parts are getting expensive now.

Most of this info and how to do it is on the web, check Mk1 Golf and mk1 Golf cabriolet as the cabriolet is the same system/spec as the Mk2 Scirocco as they was produced at the same time.

[frlrubett]

I guess the car is new to you so has it ever run right before?

Yes relatively.

I would start by replacing the servicing items, spark plugs, HT leads, Dissy cap, Rotor arm, Air filter and fuel filter.

Done the sparks and filters. Dissy and HTs were done a few years ago with few miles done since.

What is the idle speed, try increasing the idle speed, 950-1000 rpm (I find mine runs smoother at 1000 rpm)?

Ah good point, yes idles around 900

What type of fuel are you using, Super unleaded or normal unleaded and did the previous owner say what fuel the car is set up to run on as the timing is different..

Ah interesting, I always run on super and do not know what it was previously run on. Was garaged for years and changed hands a bunch of times. Will search for some info on this, unless you can point me to somewhere.

Is it always lumpy at idle or better when cold or hot?

Cold is bad, hot is better but still bumpy.


Thanks for your help.

[frlrubett]

Update on this,

Filler neck went on easily, body work was fine behind. Massive relief and the inside of the tank was pretty clean but stuck the magnets in for good measure.

When the car was up in the air today I did notice that the part I purchased from the link below was bulging in a bit. Is this anything to be concerned about?

Check the length of yours to make sure this fits.
https://www.ebay.co.uk/itm/VW-GOLF-MK1- ... SwD0lUkVOy

Thanks!

[mark1gls]

As long as it’s sealed and no petrol is leaking past the jubilee clips you should be fine, there is a lip on the tank and filler neck which could be the cause of the bulge you can see?