P0304 Engine Code
#81
#82
I am not completely sure about the 2.2 or 2.4, since I have no experience with anything but the 2.0 turbo. I'm going to guess that the 2.2 or 2.4 may also experience the same problem because I believe it has at least one of the same PCV paths via the hidden PCV valve in the intake manifold. And it's also direct injection. So my guess is that it too could have valve coking. Perhaps someone else with more 2.2/2.4 experience in this thread may chime in.
#84
Hmm, learned something new. Poking around Google, I thought for sure I saw 2.2/2.4 engine images with the fuel rail tucked under the intake. Perhaps I misinterpreted the sites I was looking at though. Nevertheless, @hurst2001, the fact that they are not direct injection basically clears them of the issue. That is, the valves will experience "fuel wash," which means they are far less likely to coke.
#85
The 2.2,2.4 oil catch can
https://www.chevyhhr.net/forums/2-2l...ormance-58332/
catch can can for the SS
https://www.chevyhhr.net/forums/how-...-can-ss-54374/
https://www.chevyhhr.net/forums/2-2l...ormance-58332/
catch can can for the SS
https://www.chevyhhr.net/forums/how-...-can-ss-54374/
#86
The 2.2,2.4 oil catch can
#87
I'm confused. @firemangeorge previously said the 2.2/2.4 were NOT direct injection. Therefore, I would assume the intake airstream would have fuel in it to "wash" the valves. Thus, why would a catch-can be needed on those engines? I understand that the catch-can separates the oil out of the airstream, but is it really needed if the engine is not direct injection?
#88
Nevertheless, I suppose I can agree that a cleaner intake airstream is always preferred over the oil contamination, regardless. So I suppose putting a catch-can on certainly wouldn't harm anything.
#90
Yes, the oil gets sucked out of the valve cover, then gravity let’s the oil run down to the elbow at the throttle body, resulting in oil being pooled in the bottom of the intake manifold.
I tried the loop hose in FMG’s picture but still the same problem, there is no PCV valve, just the vacuum of the intake manifold.
This is the factory PCV hose, straight out of the valve cover, no PVC valve
As you see here, there is a feeble attempt to use gravity to let the oil flow back into the valve cover.
This is thread in #8 Dowbrew has an explanation of the SS PVC valve and hose routing
https://www.chevyhhr.net/forums/ss-s...-hhr-ss-47584/
and better pictures in here
https://www.chevyhhr.net/forums/2-0l...tch-can-54350/
I tried the loop hose in FMG’s picture but still the same problem, there is no PCV valve, just the vacuum of the intake manifold.
This is the factory PCV hose, straight out of the valve cover, no PVC valve
As you see here, there is a feeble attempt to use gravity to let the oil flow back into the valve cover.
This is thread in #8 Dowbrew has an explanation of the SS PVC valve and hose routing
https://www.chevyhhr.net/forums/ss-s...-hhr-ss-47584/
and better pictures in here
https://www.chevyhhr.net/forums/2-0l...tch-can-54350/