|Quote, originally posted by acascianelli »|
|Where is the PCV valve located? How hard is it to replace?|
It is not just a failing PCV that is the problem. A normally functioning stock pcv system is also the source of the nasty deposits seen by so many (see referenced thread for an example photo) and as stated by VW in the patent, the source of misfire problems.
Since this pcv-derived gunk can affect so many things, improper airflow, incomplete combustion, misfiring, promoting fuel dilution, fuel injector deposits, valve deposits, who knows what else (tumbler clogging?), (sludge promotion?), other??? It seems to me getting rid of this source of gunk is crucial. If it can't be eliminated completely through a bypass system, at least a catch can should be used along with seafoaming and fuel injector cleaner use in the gas. All IMO.
From my thread here:
VW themselves, in the patent for this engine, say that eliminating the PCV would solve the deposit problems but they can’t due to emissions:
"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components.
...the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result.
...Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures.
...These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle."
"A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible. "
- Thanks to Rl_RS4 for finding this patent info. Check out his thread listed at bottom of this post for more info.
...Quote, originally posted by A3_yuppie »
Which patent are you getting the quoted passages from?
This was found by RL_RS4
Modified by saaber2 at 3:18 PM 5-19-2009
Modified by saaber2 at 3:24 PM 5-19-2009