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Leaking injector O-rings

I've been chasing some issues with my car for a while, where there was an intermittent sudden drop in specified load under boost or moderate throttle. The car would suddenly drop specified boost and close the throttle valve to 50% without reason. I finally found a trend in my logs where the MAF g/s would start to see-saw right before throttle cut occurred, and I also found that the knock voltage was a bit high on two cylinders. Here it is: I had two injectors that were leaking out of their o-rings, causing an almost untraceable vacuum leak.

   Here you can see the engine harness disconnected and the fuel rail removed:

   Here you can see the injector inlets on the manifold. The film is a tell tale sign that both air and gas were sneaking by.

   Here's the injectors that were leaking, as seen by the film above the O-rings:

   And here's a shot of the fuel rail for reference.

   The car runs great now, no more partial throttle uncertainty, the car is consistent in the way it reacts to throttle input now, and so far no more throttle cut!

Nice. Did the engine bay smell of fuel?

Shoppinit wrote:
Nice. Did the engine bay smell of fuel?

Not really, this was more less allowing unmetered air to pulled in, not fuel to escape.  So basically, a vacuum leak concentrated to two cylinders, which in turn caused knock under boost and the ecu would drop specified boost and cut throttle to protect itself. Forum Index -> Audi S6 & RS 6 (C5) quattro
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