Hello,

I have a strange problem with my RS4. when the car has sit idle for a while "don't how long!!" but first thing in the morning when I unlock the doors, open the driver door, I hear a motor run off quickly. The noise is coming from the rear passenger side of the car. The dealer says its normal, but my other RS4 never had this noise. The fuel pump was checked and is not the one making this noise. Can someone help please?

Trouble shooting this issue is hard, since when the motor runs off, it will not do it again unless you leave the car for a few hours and do it again. But it does it every morning and could be replicated.

 

At first I wondered if your car had a vacuum pump for the locks but it doesn't. In looking through parts diagrams nothing jumps out at me except for maybe the DRC dynamic ride control central valve (that's what etka calls it). I don't know if it's a motor or pump of sorts that might recognize activity when the door is opened thus preparing to drive the car. I googled the part number 8E0-616-887 and found pictures but didn't see anything that stood out as an electrical connection. If there is not supposed to be power to it, it wouldn't have any reason to make noise especially when just opening the door. Sorry I don't have anything for you other than that.

 

Thanks for trying. The dealer is giving me some lame excuse that other audi's also make this similar noise. First of all, every car has a different technology. You can not compare an RS4 to an A4 2013. They are different cars. once again thanks for trying.

 

The only thing I can think of is the fuel pump. They will run for 2 seconds when you open the door to pressurize the fuel system in anticipation of starting. It's to eliminate a long crank situation. You said it isn't the fuel pump but if it is, nothing to be concerned about. It's normal operation.

You are correct, the DRC central valve is mechanical. No motors on or in it. There are no other motors back there that would run when opening the door or otherwise that I can recall.

I still say it's the fuel pump and that's the story I'm sticking to!

 

Thanks Aspen, So you tell me that its the fuel pump and its normal. Before I bought this 2008 RS4 I had 2007 RS4. The fuel pump on the older car did not make the same pronounced noise when I opened the driver door. are the difference between the two models? If not should the fuel pumps not make the same level of noise?

 

It's PROBABLY the fuel pump. If so, it is normal.
Some pumps are noisier than others. Generally, and not to scare you, when they start getting noisy it's because it's getting worn. If not high miles (doubtful in your case) then from having bad fuel quality in the past, tank being run empty too many times (pump runs dry then), etc... One other thing, and wouldn't be a bad idea to check, is the fuel filter. If it's restricted, the pump will have to work harder and that causes it to be noisier also. The filter is in front of the right rear wheel area under the car, next to the fuel tank. It can be checked by removing it and carefully (so you don't drink some bad stuff) blow through it. Should be little to no resistance at all. If it requires pressure (like if you were blowing up a balloon for example) it's time to replace it.

As a check, remove the fuel pump fuse when you park the car and see if the noise is gone next time you open the door. If the noise is gone, it is the pump. if it's still there then....................I have no other ideas.

Hope this helps some.

 

Good call Aspen. I'd also listen to the pump with the engine running, in part to see if it's still as loud with engine running, which you know the pump will have to run then, and see if it's the same pitch as engine not running and just opening the door. This check could be difficult since the engine will absorb much of the fuel pump sound.

The other thing that likes to make noise is the fuel filter. Your car has the style that contains a pressure regulator. It cycles excess fuel under excess pressure back to the tank and does this directly from the filter rather than sending fuel to the engine and rails then back to the tank. Keeps the fuel from getting hotter than it could by running by the engine. But, I've read on this forum that this design can make a noise probably like your describing. It's possible the noise isn't from the pump but from the fuel filter which as Aspen said can operate at this time. I just wanted to throw that in there too, as Aspen could be 100% correct on the pump, his idea is what made me think of the noisy filter.
Can you get somebody to recreate the situation while you are under the car? Put your hand on that pump and see if you can isolate where the noise is coming from.

 

Thank you to both of you for all your help and advise. I will pass this on to my wonderful Audi dealer and see what they will come up with. For the benefit of all, if I do find the problem, I shall close this thread with the resolution. I hope I do!

Once again thank you.

 

The dealership dismissed that there is anything wrong with the car. They call the noise "NORMAL". I asked them if they can verify the fuel filter and ensure that it has no blockage restricting the flow. They claimed that if this was the case, the computer would indicate a failure as such. Since the computer is not providing any readings, there is not need to change the fuel filter at this time. Well I have my car back and boy do I love driving my baby!. "Don't let my wife know I said that :-)". This morning I opened the driver door in my garage and the noise came on as strong as ever but I noticed that it actually came from the driver side not the rear passenger side. I am getting more and more convinced that the turning motor noise is related to either the fuel pump or filter. Dumb question, can I take the fuel filter out and blow through it myself. How do I do that gents?

FK

 

Listen for this sound next time you start your car...get in the driver's seat and turn the key, but DON"T start the engine. THAT is the in-tank fuel pump priming the fuel rail, just like in practically every other fuel injected car. The injectors require a certain amount of fuel pressure to atomize the fuel. If the car has just been driven, you won't hear it because the rail is still pressurized. So what is the sound when you open the door? That is an electric vacuum pump "priming" the complex vacuum system that the RS4 has. If you had VAGCOM or VCDS, you could monitor fuel pressure when you open the door and when you turn the key. Guess which scenario shows an increase in fuel pressure? When you turn the key.

Some may ask "What about the high-pressure fuel pumps?". Those are the shaft driven pumps on top of the red valve covers. They "boost" the pressure in the fuel rail from the 60-70 psi that is provided from the in-tank pump to the extreme pressure required for direct injection. But these pumps are mechanically driven (engine needs to be running) and don't actually contribute much pressure until the engine is over 2000 rpm.

So to answer your question, the sound is not fuel pump related. It is perfectly normal. Sometimes you'll hear it, sometimes you won't...it depends on how long the car has been sitting.

Don't feel bad. I'd say 99/100 RS4 owners think the sound is a fuel pump. It's one of those urban myths about the car that got spread with some internet chat I suppose. I was curious myself so I figured it out. Most Audi techs don't know the car well enough to tell you exactly what's going on.

I don't have the RS4 anymore but I knew it inside and out. Google "SilverSpeed RS4 manifold" and you'll see another project I worked on. Before anyone asks, I don't provide the service anymore.