[V6-12v] Injector Hiss...

[Nathan White]

It definitely sounds like its coming from the driver side, non-FPR side,
from the injector closest to the radiator. I have replaced all vac lines
except the one coming from the EGR valve, I suppose that could be it,
but it sounds like its coming more from the front of the engine. 

This is very interesting, and I am glad I finally found a lead. It has
been throwing 02 codes, even with two different sets of brand new OEM
sensors. Codes have been cleared numerous times with VAG tool.

In addition, there are a few thick rubber hoses around the injectors,
maybe a hidden leak in one of those?

Thanks for all the help.

Car: 94 100 CSq Auto

Nathan White


-----Original Message-----
From: Elliott Potter [mailto:epotter at eep.burdell.org] 
Sent: April 17, 2004 8:13 PM
To: Nathan White
Cc: v6-12v at audifans.com
Subject: Re: [V6-12v] Injector Hiss...

On Sat, 17 Apr 2004, Nathan White wrote:

> Car has been idling rough lately. Discovered a very noticeable hiss
> coming from the driver side of the engine. Seems to be coming from one
> of the injectors. Is the injector likely dead?
>
> If I unplug each injector while the engine is running, the sound
> remains.  Oxygen Sensors (OEM), Fuel filter, spark plugs/wires, timing
> belt, water pump all replaced.

On automatic transmission cars, there's a little vacuum hose that plugs
into the top of the intake manifold in the back, right next to the fuel
pressure regulator - it supplies vacuum to the fp regulator and the
cluster of solenoid valves by the MAF sensor.  If that hose cracks, it
makes a very pronounced hissing noise and the resulting vacuum leak can
make the car run a bit rough (since the vacuum is used by the fp
regulator).  Could that be the source of the noise?  You don't say which
injectors the sound seems to be coming from, but since everything in
that corner of the engine is packed so closely together it's a
possibility.  Another thing that could make a loud hissing noise and
cause roughness would be if the gasket between the EGR valve and the
intake manifold has a crack in it.  That would be on auto or manual
cars.
--
Elliott