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[SOLVED] MK4 VR6 24V 4Motion - Fuel Pump Whines (both old and new)


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Hey guys, I just replaced my fuel pump because it was driving me crazy with all that whining and I thought it was about time to sort this out.

I purchased a brand new VDO fuel pump, installed it, turned the key on and..... it whined just like the old one!!!!!!!! You can hear in the video bellow how it whines.

A few things to note:

- I have no loss of pressure (both old and new pumps are holding steady 2.5 bar)

- Fuel pressure regulator is working perfectly (unplugging vacuum brings pressure up to 3 bar as per specs)

- My fuel tank is half full, so the whole fuel pump is submerged.

- I have no noticeable loss in power when driving, infact car runs almost perfectly

- Fuel filter has no more than 1k miles on it

 

I just want to get rid of the whining!!!

 

 

Edited by Darkbound
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Found the problem and it was not in the pump, rather one of the hoses. I assume that this will only apply to a 4motion vehicle, since the fuel tank is different, there are two hoses that join the two parts of the tank, one of the hoses whistles when you blow into it and theres NOTHING inside that hose, I can see from end to end inside it, its not clogged, its completely empty! How is it possible that this hose can cause this noise? One of the sides of that hose goes on to a valve thats on the left part of the fuel tank, but the other side of that hose goes on a plastic piece that I don't know where to mount...

 

 

 

 

This is the side of the hose thats right next to the fuel pump, does anyone know where is it mounted? I really couldnt find a way to attach it on the pump.

1TC-P4lITV_l55B_zdQ4yw.png

 

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Ahaaaa! So I have to unscrew the right side put this plastic and then screw it back... or can I slide it without unscrewing?

 

I just ordered another suction pump thats on the other side of the tank (its not new) and the hose still whistles just like the old one, I just cant figure out why????? Why are they whistling like that and what do I need to do to fix it, there is NOTHING inside the hose, I can see from end to end, if there is no way to fix it I am just going to put another ordinary fuel resistant hose to get rid of the whistling..

 

Edited by Darkbound
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You can slide it in with the screws in. (Is a little tight but does go). 

I'm not sure about the noise. 

Can you run the car without that pipe on and see if the noise dissappears. Should be ok if you have half a tank.

if noise goes is it tht pipe is just trying to suck air through rather than fuel. Maybe not located in correct place. 

Let us know how you get on

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Yes I've been running the car on half tank for about a week now, no noise at all coming from the pump, not one that can be heard when the seats are on top of it anyway... As far as I managed to research what this hose is about, it should create siphon effect between the two parts of the fuel tank, the non-fuel pump side was almost dry when we opened it, compared to the other side which had the pump fully submerged... Will put it back together in a week or so and see how it goes....

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  • 1 month later...

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