YucatanAudi

<center><img src="http://pictureposter.audiworld.com/60004/fuel_accumulator.jpg"></center><p>The fuel accumulator is a small fuel reservoir with a spring loaded diaphragm. It is used for the following:


1) Reduces noise from the fuel pump.

2) Dampens pulsations from the fuel pump, keeping the system pressure more constant.

3) Maintains a minimum system pressure (residual pressure) in the fuel system when the engine is not operating to reduce the tendency for vapor lock and provide easy starting.

The fuel accumulator is installed, using banjo type fittings, in the line between the fuel pump and the fuel filter. It is located on the under side of the car near the fuel tank.

YucatanAudi

<center><img src="http://pictureposter.audiworld.com/60004/fuel_pump_operation.jpg"></center><p>The fuel pump, located under the car near the fuel tank (along with the fuel accumulator and filter), is a roller cell type high pressure positive displacement pump. It supplies fuel to the fuel distributor at approx. 95 psi (6.6 bar).

The pump can provide more than the maximum required amount of fuel at slightly higher than normal system pressure. Fuel pressure is regulated to a lower pressure for normal operation. This ensures adequate fuel supply during high demand operating conditions (high speed-wide open throttle), while fuel circulates continuously through the system and back to the tank.

The pump operates only when the fuel pump relay is energized. The ECU energizes the fuel pump relay for approx. 5 seconds when the ignition is turned ON. After then, the relay is de-energized and the pump turns "OFF". The ECU then waits for a "cranking" signal before it will energize the relay again.

Once the engine is started, the relay will stay energized as long as the ECU is getting an "engine running" signal from the ignition system. If the engine dies, the ECU will turn the relay OFF after 5 seconds so the pump doesn't run when the engine is not running.

(And blow up after you wreck your car??? Good plan!!!)

YucatanAudi

<center><img src="http://pictureposter.audiworld.com/60004/fuel_supply_components.jpg"></center><p>Just to cover the rest...:

repeater

Nice section! Good job putting this together. good info!

YucatanAudi

would cost $80 to replace and why did I need it? Well, finally, I know. And, it sounds relatively important in the scheme of things.

I suppose putting the fuel pump, filter, accumulator under the car is safer than in the trunk, but it sure gathers gunk and rust where they are...

Maybe when I'm not busy fixing things that <i>need</i> fixing, I'll disassemble all that, paint it, and put it back together. ~ some day ~

ultrasparq

Where can i get the rubber isolaters for the fuel pump?

YucatanAudi

<ul><li><a href="http://www.clairparts.com">http://www.clairparts.com</a</li></ul>

MikTip

You will get a better responce if you phone! ;O)

YucatanAudi

-- [NO, not a telemarketer!]

and I usually can't squeeze in personal stuff. Besides, it seems "normal" that a company with a web site and a request form would answer the messages they get. Otherwise, they should change the website and say "Call This Number"!

Most places have been great about emailing....

toxicavenger70

hey thanks for the scoop, bro.