MK1 Golf GTI Petrol Tank Swril Pot

Hello All, I'm coming back to this topic since its been nearly 3 year to see if anyone has had any further information that might resolve this fairly common problem, that doesn't get resolved without aftermarket lift pumps and other fuel attachments.  Talking to a few people it seems that the  VWH GTI tank is commonly used and so I want to ask if that is the case then what else could be reducing the fuel pressure between the pump and injectors.  

I have been running a VWH tank on my 1.8 GTI for over four years and never had any fuel starvation issues whatsoever. I’ve had the tank nearly empty a couple of times and still no problems. I have heard that it’s a problem with cars that are highly tuned and cornered hard. Mine is standard but it gets put through its paces from time to time.


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The thing with new tanks and parts are subject to those who may have replaced things be feel versus replaced per the VW guidelines.

I personally have not had to replace a tank, but I have done some things that seem to be way out there…

The length of the suction pipe from the intank pump to the bottom of the tank on a 90-93 digi is imperative to the fuel being sucked from the in-tank pump to the external swirl pot, and then to the main pump.

Think of the 93 or even a latter 80's CIS system used a lift pump to lift the fuel from the tank and in to the swirl pot… (Think of the swirl pot as a Sump that fuel is fed to the primary pump where regardless of the Hard cornering, or low tank volume, it is usually kept full so that the primary pump is never starved for fuel.

Now the difference is working pressures.  CIS is @ 75psi out of the primary pump.  The Digifant is 45 psi from the output of the main pump.

The input to the swirl pot in both cases is 45psi @ 30 gallons per/hr….

So if your suction line isn't fully against the bottom of the tank then you have the possibility that the screen can be raised off the bottom and on low tank issues and hard cornering be sucking fuel as well as air…So that the Swirl pot isn't being filled to capacity.  So occasionally you have fuel starvation issues, as the CIS has more things between the Swirl Pot and the main pump, that the DIgifant doesn't it is also restrictive to the main pumps and they can suck air, and until it gets fluid filled cavitates or HUMS loudly.

Speed forward, a week prior to Christmas one year, I had a main pump failure on my 92…. So I was BS'ing with a vortexer RON, what we found out is that the VW in-tank pumps fuel flow, and output matched the primary external pump.

So with a few days prior to Christmas, I was forced to spend "big Bucks" on a new primary pump, or to spend less than 80 for a new intank pump, and remove a few things.  

I decided that since the working pressures from pumps were identical, I opted to get a new airtex in tank pump, strip out the Swirl pot, main pump fuel filter for a larger one, and all the associated fru-fru… I had to cut the metal suction tube about 3/4 of an inch to accommodate the new fuel pump and filter made sure that the new lift pump and filter was on the bottom.

I ran new hoses from the fuel return and forced it to push fuel to the right side of the tank, and replaced the connection hose with submersible rated e-15 hose from the suction side to the sender, as well as had to solder new wires from the sender to the connection for the pump.  I removed the swirl pipe, and pushed the new e-15 hose from the output side of the sender in to the newer larger fuel Filter, then to the primary (removed) fuel outlet.  Basically going to a single pump in-tank, no swirl pot.  The car ran a tad bit better, the only thing I did learn that wne the tank got to the red line, I could fuel starve on a turn (sharp at speed) but if I topped the tank at the 1/4 mark I never had that issue.  This re-make had a few bad spots, the new in-tank pump was loud and you could hear it running…Which isn't a pab thing as you knew it was working, but with the Radio up you didn't hear it.  With the top down you didn't hear it.  This ran for over 9 years until I had the new-in-tank single pump failed… Turn the car to run with all noise down as in the fan off, the radio off it wasn't making a sound… so I had to replace the 55 dollar larger pump…

Now when my Blonde daughter borrowed the car, she would not fill the tank when it was at the 1/4 but waited for it to be at or below the red…So I got called out because as she turned a corner the car stalled…..When I told her to get gas..she said why it isn't on empty…

You can't understand blonde womens thinking on things…  I said what part of keep the fuel above 1/4 tank didn't you understand..and it was the second call I got for the same issue that I said Keep the Tank at 1/4 or more at all times.  She burned so many Honda pumps on her Honda that I lost count…(glad I bought them with the LLW and they all failed within the 1 year full warranty.)….. So I told her that if it didn't run good with 5 dollars of gas, then I would look at it.  I drove the car flawlessy for about 2 months to prove the point and let her drive my other Cabby…..

So you can have cornering issue if the in-tank or fuel suction line isn't fully against the bottom of the tank nd you like to drive it to the red..or in my daughters case below the red.
You can go without the Swirl pot…just have to drive it less zippy.  And for a final check I made sure that an OEM in-tank pump worked just fine, after I by-passed my main pump for a test….

Thanks for the posts Lads.  The pick up pipe on mine runs straight into the swirl pot, I've seen pictures of the pick up pick turn down at a slight angle.  Could this be the difference in what I have and the VWH tank, has anyone a picture of the VWH tank?  
If as Saulty says they should run fine, what other issues could cause the fuel issue?  any ideas?

basically the aftermarket tank swirl pot is a more primitive design, so wont work as nice as the oem pot does. some people have issues with tham and some dont. could just be the pot design is perfectly fine just some of the tanks arent made properly

I had my GTi tank overhauled by Hartlepool Radiators….they did an excellent job, not cheap but good quality. Also gave a written warranty. I did a lot of search, I wanted to keep the original design as i didn't want to make mods as it was more of a headache and buying a second hand there is still the risk of being an overhaul due to rust, so I just overhauled my original tank instead.

They had to cut the cover of the swirl pot in order to overhaul it properly but managed to install the lid back on and I was able to install the filter.

This is the link to my post, hope this helps:
View topic: 1983 MK1 Golf GTi Fuel Pump Relay - The Mk1 Golf Owners Club

Hi All,  Still have the fuel starvation issues and working from the tank forward, checked the accumulator for fuel coming out the screw at the back and nothing so assuming its okay.  I did notice that the pipe going from the fuel pump to the accumulator was in a funky circular formation. As you can see its like a pigtail, and I was wondering if this was correct or should it be a go directly into the accumulator.    

2021-04-02_08-37-18.pdf

larmstrong said

Hi All,  Still have the fuel starvation issues and working from the tank forward, checked the accumulator for fuel coming out the screw at the back and nothing so assuming its okay.  I did notice that the pipe going from the fuel pump to the accumulator was in a funky circular formation. As you can see its like a pigtail, and I was wondering if this was correct or should it be a go directly into the accumulator.    

2021-04-02_08-37-18.pdf

Difficult to tell but have you highlighted the accumulator to engine bay fuel line pipe?, see link.

My GTi has always kanngerooed if less than 1/4 full on wide fast roundabouts. As its apprently a rubber flap that in the tank that can't be replaced I just live with it as a MK1 quirk.

https://www.heritagepartscentre.com/uk/171201218c-fuel-line-accumulator-to-main-fuel-line-k-jetronic.html

EDIT: This is what heritage list as pump to acc, but looking on the old interweb the same parts get labled with both descriptions at random;
https://www.heritagepartscentre.com/uk/171201220d-fuel-line-accumulator-to-fuel-pump-k-jetronic.html

Thanks that looks like the two pipes alright, I could have mixed up which pipe was going where as I didn't take off the wheel.  Going to put a pipe from 5ltr drum directly into the pump and determine once and for all if it is the tank or not.  I just can't believe that so many GTI owners live with this problem.  It wrecks my head when the tank gets down to just about when it starts happening and you throw it into a good sharp corner only to have your head thrown against the steering wheel on the exit.    

You can't mix up the two connections on the fuel accumulator. They are 2 different sizes. The braided hose that connects to the lower connection on accumulator is supposed to have a loop in it. There is a YouTube video showing the Mk1 CIS  parts and you can see that hose and it's looped. Also, that looped hose goes from the accumulator to the engine bay. It is not from fuel pump to accumulator.  I currently have the fuel starvation on right turns when less than full.