Help please

Can anyone give me some advise please. About 2 months ago I ran very low on petrol and the engine cut ou like i had run out. I put some more petrol in but the engine wouldn't start. Went back to tow the car home after 2 hours and the engine fired first click. Since then every two weeks or so the engine will die and won't start for about half a hour. Then it starts like nothing is wrong. Problem is I can't seem to find any problem because it's hard to look for when the engine is working fine?? Anyone had this problem or point me in the direction of fault finding?
 Cheers Andy

Forgot to add its a 1986 1.8gti

Stating the obvious you've sucked up the cr^p from the bottom of the fuel tank most likely.

Do you have an inline fuel filter?
Check that first and then you're going to have to work through the whole fuel system but there are guys with far more knowledge on this subject that will comment after me!  

Hey bud.. as golf Cabrio suggested you may this issue… firstly is you Fuel filler neck rusty at all?? check this, then check your tank for any debris floating about in the bottom - check this by removing your back seat - 2 screws, slide out your seat & your will see a black circular sender cover - undo this, be careful as this is the fuel sender unit, shine a torch/bright light there & you should see any debris, if any, in the tank.. is this is the case, then there will be debris in your fuel system. This meaning cleaning the tank out, replacing the Fuel Filter, possible fuel line clean/blow out as well & hope that the gauzes on the Warm Up Regulator have not become contaminated.

I'm sure the Dub legends rubjonny & Briano1234 will advise on this..

Worst thing you can do with an old car with an old metal fuel tank is run out of petrol, always try and keep it above 1/4 tank.

You have properly sucked up all the dirt and rust at the bottom of the fuel tank and blocked the fuel system, start at the fuel tank end and clean the pick up filter (hopefully you have one fitted to the end of the pick up?), then move to the fuel pump, there is a little filter on the input of the pump, then move the big fuel filter in the engine bay and fit a new one.
If all that cleaning works then great news job done.
If not you will need to undo the fuel lines and blow air down them to clear out the lines.

Sounds like a plan. 
I'll give it a go and fingers crossed. 
Thanks all for the advise. 
Cheers Andy. 

have a look at this bud…

View topic: Fuel Tank cleaning *HowTo* clear that blockage - The Mk1 Golf Owners Club
 

Nice one thanks 👍

Here are my thought on this.

When you run a car for repeated cycles below the 1/4 tank (On the highway travels is one thing, but daily driving putting in a couple of liters of gas repeatedly is another.) .

You open your self up to clogging filters, and pump up with debris whether it is Rust, Water, garbage.

You also deprive your in-tank pump from submersion in fuel which the pump is using to dissipate heat.

Your in-tank pump uses fuel to cool, and to lubricate.
The Filter screen can fall off.  This allows contaminates to enter your fuel system as the pumps are Vane type, that is a spinning wiper blade they can get crud stuck between the housings and the vanes of the pump.

If the Pump is sitting in 1/4 tank of petrol, then it can't cool itself off, and the fuel it is pushing through the system is lacquering internally as it is evaporating and sticking to moving parts.  When you stop the car and it is cooling this lacquer is hardening to eventually stop the motor, if the motor doesn't over heat and stop on it's own.

On a CIS system there is the Sump, the Accumulator and the Check valve between the engine and the External fuel pump.  These too can cause fuel delivery issues.

If you hear a loud whine from the right rear axle area then your main pump is being starved for fuel and that is it complaining.  

There is also the interconnect hose between the In-tank pump and the sending unit that deteriorates or holes, and when the fuel is below it, it shoots fuel into the tank, and not to the main pump.  It has been known to break, and drop the in-tank pump in to the bottom of the tank causing a fuel starvation issue in the main pump.

There are more things between the engine and the Fuel tank on a CIS, than a Digi based injection, but from what I have read, and seen is that the CIS is Just as finicky as the DIGI.

The Sump (filter) that is clipped on the side of the tank is where the 2 fuel pumps connect, the main pump draws it's fuel from there and that is where the in-tank pump pumps to.  So if your in-tank pump fails, the main pump has to suck fuel all the way back to the tank, and it whines…..Like a kid wanting more candy, until it just sits down and stops functioning (over heating).  Sometime it will cool off and re-start.  But when overly hot will start lacquering the fuel as well eventually killing it.

The only differences is that the Fuel Pump Relays on CIS cars tend to over heat and develop cold solder joints in them that will part from the contact points and the car stops pumping fuel.  When it is allowed to cool between 2 to 10 minutes, the cold solder joint hardens makes contact and you can start your car… Rinse repeat until you replace it.

For the Whining main pump, you have to investigate it as the strain of it trying to pull fuel from a clogged system will  eventually cause it to fail as well.

 Changing the Filters is a good start, verifying that the tank is free of debris is another, as well as making sure that your in-tank pump if equipped is still functional.

Tolusina on the vortex has a good how to on Digifant based rides to get rid of the In-tank, Sump hoses and  external pump with a single low cost in-tank pump.  I have done this conversion on one of my digi cars and although you hear the pump running, it hasn't failed, or given me any issues and at a week before Christmas, spending 80 dollars instead of 3-to-4 hundred was a godsend.

For what it is worth.

PS, you need 3/4 or less of petrol prior to inspecting the tank. Take care of winding the Sending Unit float arm as you remove the sending unit from the tank.

This sounds very familiar to me ! I also have a 86 gti and had the same symptoms. Does your car cut out no matter what the engine speed is ? Like someone has just turned the ignition off ? If so change the fuel pump relay ! For some unknown reason my faulty relay was cutting power to the coil causing zero spark. After the relay cooled down it would start again as if nothing was wrong. I couldn't figure it out till someone on here mentioned to relay !!

Wow.  Loads of info. 
Thanks everyone. 👍👌👍

Did you get to the bottom of this ?

Just waiting on the fuel to get below a quarter then I'll get the back seat out and start the cleaning process. I'll keep you posted mate as hopefully going to tackle it Monday.