Fuel accumulator

sinbin5t · 29-07-17, 12:37 PM

Probably a silly question to some of you but i have to ask

Should air blow both ways on a fuel accumulator as in blow on one pipe and air comes out of the other, then blow on the other pipe and air comes out of the first one ?
I don't know how these work so don't know if the above says it's goosed or not

Thanks

jimh · 29-07-17, 08:28 PM

Yes, I would expect to be able to blow air though it both ways.

To test it, you need to pressurise it with fuel, then remove the small screw in the end of it (opposite end to where the fuel pipes attach).
If fuel squirts out when you remove the screw, it's goosed.

All that is in there is a diaphragm and a spring. If the diaphragm has a hole in it, fuel can get into the spring area and will leak out when the screw is removed.

sinbin5t · 29-07-17, 08:40 PM

Quote:

Originally Posted by jimh

Yes, I would expect to be able to blow air though it both ways.

To test it, you need to pressurise it with fuel, then remove the small screw in the end of it (opposite end to where the fuel pipes attach).
If fuel squirts out when you remove the screw, it's goosed.

All that is in there is a diaphragm and a spring. If the diaphragm has a hole in it, fuel can get into the spring area and will leak out when the screw is removed.

Thanks for that jimh, will give that a go

Gaz · 14-08-17, 04:04 PM

Don't run one on my cq anymore. Car seems to run okay without it to me. Am I missing something as to what you need one for?

simons2 · 14-08-17, 04:08 PM

Holds pressure in the fuel system when the pump is off, just means the car should fire instantly with one fitted or you will have to crank it more without one.

Colin Aitchison · 14-08-17, 06:51 PM

Quote:

Originally Posted by simons2

Holds pressure in the fuel system when the pump is off, just means the car should fire instantly with one fitted or you will have to crank it more without one.

I'm with simons2 on this one, the one for my Ur quattro was £154 from quattro corner in 2012, but the car should start and run without one.

sinbin5t · 14-08-17, 07:00 PM

Quote:

Originally Posted by Colin Aitchison

I'm with simons2 on this one, the one for my Ur quattro was £154 from quattro corner in 2012, but the car should start and run without one.

They are a lot of money for what they are.
Apparently the idea is for stopping hot start problems by keeping fuel pressure there, my 5T has never had one since the day i got it many years ago, buuuut, on very hot days with a hot engine it could be slow to start. Just my experience

Gaz · 14-08-17, 11:57 PM

Quote:

Originally Posted by sinbin5t

They are a lot of money for what they are.
Apparently the idea is for stopping hot start problems by keeping fuel pressure there, my 5T has never had one since the day i got it many years ago, buuuut, on very hot days with a hot engine it could be slow to start. Just my experience

Unless you are driving long distances all day with lots of stopping and starting all the time, I don't think you will notice much of a problem without it fitted.

As a side point, would fuel flow be any better without it fitted? Seems to me that removing it would be one less obstacle/restriction in the system.

sinbin5t · 15-08-17, 02:14 PM

Quote:

Originally Posted by Gaz

Unless you are driving long distances all day with lots of stopping and starting all the time, I don't think you will notice much of a problem without it fitted.

As a side point, would fuel flow be any better without it fitted? Seems to me that removing it would be one less obstacle/restriction in the system.

Point 1) I did say it was SLOW starting on a hot day with a hot engine, having said that, i don't know what difference a fuel accumulator would or wouldn't make as the car has never had one while i have owned it.

Point 2) I wouldn't know, i am hoping somebody with the knowledge will reply though

msh · 15-08-17, 02:18 PM

It doesn't matter really - there are heavier restrictions in system, like fuel filter, and you won't feel it in any way, unless, maybe, running some very powerful 10vt engine still with K-jetronic, and only then on full boost approaching redline...

29-07-17, 08:28 PM	#2
jimh Grown up member Classic Audi Club Member Join Date: Dec 2008 Posts: 122	Yes, I would expect to be able to blow air though it both ways. To test it, you need to pressurise it with fuel, then remove the small screw in the end of it (opposite end to where the fuel pipes attach). If fuel squirts out when you remove the screw, it's goosed. All that is in there is a diaphragm and a spring. If the diaphragm has a hole in it, fuel can get into the spring area and will leak out when the screw is removed.

14-08-17, 04:04 PM	#4
Gaz Senior Member Join Date: Jul 2007 Location: Five Cylinder heaven Posts: 1,493	Don't run one on my cq anymore. Car seems to run okay without it to me. Am I missing something as to what you need one for?

14-08-17, 04:08 PM	#5
simons2 Grown up member Classic Audi Club Member Join Date: Jun 2012 Location: ireland Posts: 291	Holds pressure in the fuel system when the pump is off, just means the car should fire instantly with one fitted or you will have to crank it more without one.

15-08-17, 02:18 PM	#10
msh 4 ring whore! Join Date: Jun 2008 Location: Rucava, Latvija Posts: 3,816	It doesn't matter really - there are heavier restrictions in system, like fuel filter, and you won't feel it in any way, unless, maybe, running some very powerful 10vt engine still with K-jetronic, and only then on full boost approaching redline...