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I have seen fuel go off and go to varnish but never heard the acid thing. Maybe it was just that brand of fuel that did that?

hi there,
Interesting you mention a quiet full pump.. My VS V6 has a quiet full pump. My VR V6 you can hear loud and strong. I started to wonder if there was some thing wrong with the quiet VS pump?

Pete

From my experience the noisy pump is suffering cavitation on the suction side. When teaching full time fuel systems was one of my subjects and I did a demo and restricted the intake then the output side of a pump and it made people appreciate that most times a noisy pump is a blocked pickup filter.

Pumps have become more quiet over the years as manufacturing tolerances have improved.

My new AC delco/Delphi pumps are way more quiet than original low K ones I have.

I think the repair to my fuel return line in the tank probably contributed the most but yea they have got quieter. I have searched the net for support with my statement about fuel going acidic and it seems to get back to Ethanol and water. The air in the tank causes oxidation which causes rust and accellerates the breakdown of fuel so I'm thinking it's best to keep the tank full if I'm not using the cars. That will cost me a fortune on todays prices.

vlad01 wrote:Pumps have become more quiet over the years as manufacturing tolerances have improved.

My new AC delco/Delphi pumps are way more quiet than original low K ones I have.

Where do you get your acdelco or Delphi pumps from?

Charlescrown wrote:From my experience the noisy pump is suffering cavitation on the suction side. When teaching full time fuel systems was one of my subjects and I did a demo and restricted the intake then the output side of a pump and it made people appreciate that most times a noisy pump is a blocked pickup filter.

A blocked pickup filter, is that the small gause bag that sits on the end of the tube?

When I prime the VS V6 I can hear a similar sound to bubbles. I wonder if there is an issue when It has a long cranking time.

Yes. Sometimes called a sock filter. You may have the same issue as I did. The return line in the tank decomposes over time and falls apart. View this clip https://www.youtube.com/watch?v=ASu_GXxM0xI&t=172s it shows you what goes wrong and how to fix it. The return line needs to be directed into a swirl pot to ensure the pump has a full head of fuel as the tank level gets low.

Charlescrown wrote:Yes. Sometimes called a sock filter. You may have the same issue as I did. The return line in the tank decomposes over time and falls apart. View this clip https://www.youtube.com/watch?v=ASu_GXxM0xI&t=172s it shows you what goes wrong and how to fix it. The return line needs to be directed into a swirl pot to ensure the pump has a full head of fuel as the tank level gets low.

I just finished watching this video. I've replaced the fuel pump before, its fidley but easy enough. I recon the hardest part will be fitting the new fuel hose onto that swirl pot barb inside the tank. Hopfully my swirl pot barb will come away to make it easier.

how was yours Charlescrown? or any one else.

Those swirl pot venturi fittings are very hard to removed even if you have the swirl pot removed in a destructive way. You will have to pull the hose off in situ.


As for the pump brands, any good auto shop should be able to get genuine ones. Or holden dealers, ebay otherwise.