Fuel filter

**B6 Dude** · 07-09-2008 11:34 AM

Zero search hits for this in the B6 forum.

Looking into replacing the fuel filter for general maintenance (no probs really), and I see "fuel filter with pressure regulator" available at GAP. Autozone doesn't have it for this car. Is the regulator really an integral part of the filter, or can I get the filter individually somewhere?

Cheers,
-Neil.

**dougyfresh** · 07-09-2008 11:44 AM

here you go: http://forums.audiworld.com/a4gen2/msgs/917681.phtml

**Arclight** · 07-09-2008 12:11 PM

Search under the B6A4 forum only. Someone recently posted a whole "how to" here w/ pictures.

**B6 Dude** · 07-09-2008 12:14 PM

The B6 search should've covered all B6 subforums, but I can try again. At this point I'm really just interested in knowing if I have to swap the filter with the regulator or if there's just a filter (w/o) regulator available. That AW thread btw is missing the pics :(

**B6 Dude** · 07-09-2008 12:17 PM

Actually, that is what I had tried, since B6 is B6A4 :) Just tried again, and now I get only this post.

**dougyfresh** · 07-09-2008 12:22 PM

I think the search function isn't working correctly on AZ right now. I can't search for certain keywords I know for a fact I have typed. It comes up "can't find it".

**B6 Dude** · 07-09-2008 01:56 PM

Ahhh... that would explain a lot. But I was placing an order for oil etc, so I ordered the fuel filter with the regulator anyway. They (GAP) said that's the only way they know that it to be available.

Thanks,
-Neil.

**orb** · 07-09-2008 03:55 PM

here's the writeup with the pictures. http://automotive-diy.com/AUDI/A4/A4_8/A4_8.html

**brewmastr** · 07-09-2008 06:23 PM

there is no regulator in the fuel filter, there is a check valve, but our cars use a returnless fuel system, ME varies the voltage to the fuel pump to control the fuel pressure.

**old guy** · 07-09-2008 06:28 PM

Actually there is a crude regulator of sorts in the filter. The return line is controlled by a spring loaded valve that opens to help maintain a fairly even pressure on the delivery system.

**brewmastr** · 07-09-2008 06:37 PM

i fail to understand old guy, if the system is not returnless, meaning it returns at the filter how does it differ pressure from idle to WOT, as i understand it is a returnless system, and ME controls the voltage to the pump? is it a damper in the filter, i can understand that.

**old guy** · 07-09-2008 06:55 PM

The returnless system was one of the biggest hurdles that the tuners had to face when it first came out. Typically with a turbo motor the fuel system pressure regulator gets an "adder" from a boost signal line to help maintain a constant fuel pressure delivery. So if you wanted more fuel you didn't have to change the injectors, just turn up th pressure regulator (within reason). with the returnless system the fueling has to be controlled by the injector duty cycle since the pressure differential changes with boost pressure rather than remaining a constant.