Sounds like a TDI at idle

**IceMole** · 05-01-2008 03:12 PM

So I picked up a B7 quattro 6sp in QM and I guess I never noticed when I test drove it but when you're outside during idle, it sounds like a TDI. Is this something normal? I did search around and found it's a little noisy but I didn't think it would be this bad.

**dave405nyc** · 05-01-2008 03:14 PM

FSI pump working: totally normal

**acbrooks2** · 05-01-2008 04:09 PM

The FSI is a diesel-based engine so it sounds kinda like one - get an exhaust and you'll never look back!

**IceMole** · 05-01-2008 04:15 PM

Waiting on the AWE quad

**a4dc89** · 05-01-2008 05:07 PM

The consensus is that the 2006-early 2007 fuel pumps are noisy and cause the car not to start when it is cold out. Audi should really confront this problem

**AUDI101** · 05-01-2008 05:11 PM

My 2006 stalled a couple times this winter i also thought i had a problem with my motor when i first got my car and wad told by the Dealer its the FSI i do have 3.2L but still same issues

**Mike@APR** · 05-02-2008 12:20 AM

Originally Posted by IceMole

So I picked up a B7 quattro 6sp in QM and I guess I never noticed when I test drove it but when you're outside during idle, it sounds like a TDI. Is this something normal? I did search around and found it's a little noisy but I didn't think it would be this bad.

The majority of the noise is coming from the injectors opening and closing. We have an injector flow bench at APR and I was able to run the injectors in a quite room and it sounds identical to what you hear standing in front of the car while it's idling. As already stated, the fuel pump is also making some noise.

The injectors have to open and close under some tremendous pressure from the FSI fueling system. System pressures for the FSI engines typically range from about 50 Bar (725 PSI) to about 120 Bar (1740 PSI). This is not even close to common rail diesel which can be around 1600 Bar (23,206 PSI) [O_O]

Mike

**RedS-line** · 05-03-2008 02:09 PM

when i shopped around for a cpo audi i noticed that some a4's idled more noisily that others. my guess is that some were not maintained that well or were just beat up more.

**Auditude2.0T** · 05-03-2008 07:57 PM

The FSI pumps in the RS4 makes the car sound superchared in low rpm's.

**Laconvail** · 05-03-2008 09:56 PM

I think more of that noise is from the gear driven engine accessories. And they have addressed that problem with the fuel pumps. They have issued a tech bulletin about it.

**4-tified** · 05-05-2008 09:33 AM

Originally Posted by acbrooks2

The FSI is a diesel-based engine so it sounds kinda like one - get an exhaust and you'll never look back!

There are diesel and gas engines that use FSI.
But, the 2.0T is based on the old 1.8T with the newer Audi FSI technology.
The gas FSI doesn't sound like it does because it's "diesel-based".

The FSI is a gas engine, based on a gas engine.
The "FSI", which uses a high pressure fuel system with it's combustion located fuel injectors, along with high compression for a turbo engine (10.5:1) is what gives the 2.0T FSI it's unique tonal quality.

A diesel engines sound is caused from how the a/f mixture ignites, which is basically detonation from compression/heat, and not from a spark like in a gas engine. Sometimes a "glow plug" is used to help ignite the a/f mixture, especially when the outside temps are very cold, and/or the engine doesn't or can't produce enough compression to ignite the mixture on it's own. Quite different from how a gas engine does it.

**a4dc89** · 05-05-2008 09:36 AM

Originally Posted by Auditude2.0T

The FSI pumps in the RS4 makes the car sound superchared in low rpm's.

not the fuel pump, all the other belts and stuff sounds the same on many other high performance cars

also i didnt realize they had a technical service bulletin, someone have it in writing? i am gonna go to the dealer asap