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faulty/stuck one way valve symptoms?

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo's stylish, distinctive "P2" platform cars.

2001 - 2007 V70
2004 - 2007 V70 R
2001 - 2007 XC-70
2001 - 2009 S60
2003 - 2007 S60 R

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darrylrobert
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faulty/stuck one way valve symptoms?

Post by darrylrobert » Thu Apr 16, 2020 3:48 am

Ive found a faulty/stuck one way valve under the inlet manifold (white valve in pic), air flows in both directions when it should only flow in one direction. The valve goes from the inlet manifold to a t-fitting. Left goes to another one way valve then to the air filter to turbo pipe. Right goes directly to the tank purge valve.

So basically there is a free airway from the inlet manifold to the tank.

No fault codes

Would this be causing the hard/prolonged starting when hot?..im hopeful it is just asking you guys?

Ive also found some issues with design of the 2001 purge valve, so i will replace it with the updated 2002 version (see pic)
valve update.jpg
purge valve

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oragex
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Re: faulty/stuck one way valve symptoms?

Post by oragex » Thu Apr 16, 2020 5:51 am

Hmm, would that cause a hard start.. ? I don't really see why, unless it's a computer thing. I'm assuming this is the gasoline engine ? Maybe try uploading a video
See my video with the non turbo one from a 2003. There's no flow either way when closed, and flow towards the engine when opened electrically. If yours is stuck open, that would not be a problem for the engine, except I would guess the gas tank vapors are always leaking out when the engine is off and cannot burn them. The problem is when the valve is stuck closed, mine did so, the car would start fine but after a while the engine would loose power and get a check engine (if that happens just undo the vapor hose temporarily until replacing it). Worth testing your PCV while there, it may have an effect on these components if it's clogged

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Re: faulty/stuck one way valve symptoms?

Post by jimmy57 » Thu Apr 16, 2020 6:40 am

The check valves in the purge valve lines between valve and the intake for one leg and the inlet pipe to turbo on the other leg, are to assure that vapors are drawn through purge valve when it is open with or without intake pressurized by turbo. As already stated, the purge valve would have to be stuck open for a check valve to cause long cranking from the engine being flooded with gasoline vapors from charcoal storage canister.

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