audi b6 cabrio 2.5tdi wont start . can you normally hear fuel pump in tank

steve elliott

Registered User
Hi Guys cars been sitting for a while tried to start it the other day ,just turns over.No smoke so definetely fuel problem . I cant hear the fuel pump in tank when i switch ign on. Is this normal?
I pulled the plug off top of tank put a multi meter between brown and green/yelow wire ,and i have power but only in start position .Seems to suggest power only goes to low pressure pump when in start position is this right ? . This would mean i wont hear it , if it is working as sound is drowned out by engine cranking
Any ideas ?
Cheers Guys
 

Mike B

Registered User
I can only say that I have never heard a pump when starting my Avant or just with ignition on.Hope you fix it
 

steve elliott

Registered User
Well another foo pah ,as i didnt do the basics .ie crack off the inj pipes! After a few seconds bubbles appeared ,then fuel .secured them and away it went . Dont know why but it appears fuel has dropped back to the tank,despite it having over half a tank . I had drove it out of the garage 3 weeks ago to give it some tlc .It started immediately after sitting in garage for over 6 months . Incidentally tank pump only gets power in start position oddly .ie no priming prior to attempting to start,as is more common i think . I got the missus to turn the key while i listened with a stethoscope .whirring away! .Thats when i cracked off the injectors . Live and learn etc .
 

Mike B

Registered User
It did sound like air in the fuel line.It might have a leak somewhere which can be hard to trace but strange if it was ok before
 

steve elliott

Registered User
Yes was definitely air in system .How it got there is a mystery .It has got 2 what look like aftermarket non return valves in fuel lines, under bonnet ,so maybe its had issues historically !
 

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