View Full Version : Oil cap removal disturb the engine idle rpm.
MadRacer
02-01-2014, 02:10 AM
Hello,
I just remove the oil cap while the engine works in idle and there was suction while removing it.
This cause disturbance of the engine works. See video. I have doubts about PCV ... what is your opinion?
http://www.youtube.com/watch?v=swgz60Lg1l4
fly300kts
02-01-2014, 05:00 AM
Search for more details and that's normal
Phil
MacFady
02-01-2014, 06:26 AM
Why are you doubting PCV? That is exactly what I would say it is from your description and the video. CEL? Are you idling a little higher than usual?
MadRacer
02-01-2014, 06:46 AM
I saw a similar video with description "problematic PCV symptoms". No CEL no errors in VCDS but i have problems with the first start. The engine wont start from the first time. Any ideas ?
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Mishaudi
02-01-2014, 06:57 AM
N80 valve
http://www.audizine.com/forum/showthread.php?t=401986
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aluthman
02-01-2014, 07:06 AM
You want there to be a vacuum. Pressure means you have a bad PCV. The idle thing is normal.
You want there to be a vacuum. Pressure means you have a bad PCV. The idle thing is normal.
Like most people said, this is normal.
When i had start problems i changed the following:
N80/Purge valve, thrust sensor and fuel filter. This somewhat fixed it but i when the weather dropped I had cold start problems.
Gas Cap gasket. BINGO! This fixed my cold start problems instantly. I hate throwing money at good parts, but my CEL indicated problems so changed what was noted in these forums. I forgot what code vagcom gave, but it is the low pressure code.
MacFady
02-02-2014, 05:54 AM
You want there to be a vacuum. Pressure means you have a bad PCV.
Your problem may not be a PCV, but I have never seen one thread that indicated oil cap pressure was a bad PCV, only excess vacuum on the cap and dipstick at idle.
Your problem may not be a PCV, but I have never seen one thread that indicated oil cap pressure was a bad PCV, only excess vacuum on the cap and dipstick at idle.
Yep. I've always read that vacuum on the cap is bad. But, that's super counter intuitive to me. So much so that I asked why in the dumb questions thread. :). Unfortunately, it didn't get answered. :(. Maybe someone will explain it here :)
4rings5stars
02-02-2014, 06:41 AM
Since the area under the valve cover is being purged using engine vacuum, it seems you would be creating a vacuum leak opening the cap.
That's the way I understand it fwiw
I'm still confused by that though, because if the pcv is failing, doesn't pressure build up and break your vc seal? If so, how can there be vacuum?
4rings5stars
02-02-2014, 07:34 AM
I think it happens during boost. Not 100 percent on that though