Iky Posted March 25, 2012 Share Posted March 25, 2012 Is the stock bov always open? Ive just disconnected one of the hoses which goes to the inlet and it seems the bov is always open and the boost is leaking into the inlet with a little rev. The car seems to drive ok as far as I can tell apart from my really bad mpg problem. There is always a fuel smell on startup. Quote Link to comment Share on other sites More sharing options...
Iky Posted March 26, 2012 Author Share Posted March 26, 2012 Anybody know exactly how the stock bov works? Quote Link to comment Share on other sites More sharing options...
mellonman Posted March 26, 2012 Share Posted March 26, 2012 yes its all ways open iirc,when its not on the car anyway, it has to be under vacuum to close you can test this by removing it and blowing through it then put a vac pipe on it suck and clap it the try and blow through it. this is not the best way to test it though Quote Link to comment Share on other sites More sharing options...
Robzki Posted March 26, 2012 Share Posted March 26, 2012 put a vac pipe on it suck and clap it the try and blow through it. Is there still good money in translating user manuals from Japanese to English? Quote Link to comment Share on other sites More sharing options...
mellonman Posted March 26, 2012 Share Posted March 26, 2012 Is there still good money in translating user manuals from Japanese to English? come on i missed out a "m" out of clamp. owh yeah blow through the bov not the vac pipe Quote Link to comment Share on other sites More sharing options...
Iky Posted March 26, 2012 Author Share Posted March 26, 2012 I understand, thankyou. Although I did try that with my mouth but it still didn't hold closed. Maybe i'm not such a sucker after all Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted March 26, 2012 Share Posted March 26, 2012 The stock BOV should be held closed by its internal spring if the engine is not running. If the engine is running in a vacuum condition (e.g. throttle fully or partially closed), the valve will be opened as the spring pressure will be overcome by the differential pressure across the piston caused by the reference to the intake vacuum. If the engine is not in a vacuum condition (e.g. throttle fully open, under boost) the spring pressure will be assisted by the intake pressure to hold the valve closed. Quote Link to comment Share on other sites More sharing options...
Iky Posted March 26, 2012 Author Share Posted March 26, 2012 The stock BOV should be held closed by its internal spring if the engine is not running. If the engine is running in a vacuum condition (e.g. throttle fully or partially closed), the valve will be opened as the spring pressure will be overcome by the differential pressure across the piston caused by the reference to the intake vacuum. If the engine is not in a vacuum condition (e.g. throttle fully open, under boost) the spring pressure will be assisted by the intake pressure to hold the valve closed. So, that kind of contradicts what Mellonman has said. What is the answer then? Throw it in the bin and block the pipes? Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted March 26, 2012 Share Posted March 26, 2012 What is the answer then? Throw it in the bin and block the pipes? That's one way of dealing with it You could always replace it with a used one. They are listed in the "for sale" area of this site quite often; normally for little more than postage. Quote Link to comment Share on other sites More sharing options...
mellonman Posted March 27, 2012 Share Posted March 27, 2012 The stock BOV should be held closed by its internal spring if the engine is not running. If the engine is running in a vacuum condition (e.g. throttle fully or partially closed), the valve will be opened as the spring pressure will be overcome by the differential pressure across the piston caused by the reference to the intake vacuum. If the engine is not in a vacuum condition (e.g. throttle fully open, under boost) the spring pressure will be assisted by the intake pressure to hold the valve closed. are you totally sure about that as when i took mine off you can clearly blow through it,until you put the vacuum on it, i know in theory that it should be closed like all othe bov but when i checked mine as i thought it had a leak, that was the only way i could get it to close. Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted April 2, 2012 Share Posted April 2, 2012 are you totally sure about that as when i took mine off you can clearly blow through it,until you put the vacuum on it, i know in theory that it should be closed like all othe bov but when i checked mine as i thought it had a leak, that was the only way i could get it to close. It sounds like your valve had failed: Quote Link to comment Share on other sites More sharing options...
Iky Posted April 2, 2012 Author Share Posted April 2, 2012 Nice one Andy! Thanks for that. Quote Link to comment Share on other sites More sharing options...
Iky Posted April 2, 2012 Author Share Posted April 2, 2012 so would this be whats causing my car to overfuel? Quote Link to comment Share on other sites More sharing options...
mellonman Posted April 3, 2012 Share Posted April 3, 2012 nice one andy,my memory much be failing lol Quote Link to comment Share on other sites More sharing options...
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