I can only think there is a fault somewhere in the pcv system that has somehow been overlooked.
The vacuum part of the pvc system provides the motive power for the flow of clean fresh air through the crankcase and into the inlet manifold via two routes, taking with it the various crankcase emissions to be burned up during the combustion process.
At idle and low revs and other times when manifold depression is high, such as during overrun, crankcase emissions tend to be drawn through the pcv valve directly into the manifold and at other times, when engine speed and load increases the venting increasingly takes place through a second vent into the air cleaner or intake. At low speed, etc. the second vent becomes the supply of clean fresh air for the crankcase.
In the early days of the pcv system some engines had fresh air supplied via a filter fitted to the crankcase and others used a vented oil filler cap. A few engines had no air inlet at all and the manifold was simply connected directly through a length of half-inch hose to the valve cover. Those engines almost never leaked oil...
For a few years BMC used a complicated vacuum regulator valve mounted on the crankcase and again a large bore hose to the manifold.
Since those days most manufacturers have settled on one of two systems using either a pcv valve or a small air bleed into the manifold to provide the motive power for the ventilation of the crankcase. Mostly there is a flame or spark arrestor/oil mist trap in the breather that sometimes becomes blocked and causes trouble, though the trouble is usually the opposite of too much vacuum.
I suggest you go back to the drawing board and recheck everything. During a service I usually test the breather by putting the compressed air blow-gun down the dipstick tube and sealing it with a cloth. If the crankcase breather is clear and working properly no pressure will build up inside the engine.
Obviously some caution is needed to avoid blowing out seals and gaskets if the breather is found to be inadequate.
SOURCE: 2004 Mazda MPV vacuum line from pcv valve and
You have the wrong type hose on the pcv valvle. It isn't vacuum hose.
Testimonial: "thank you you have been very helpful i understand now but the hose that is on the new pcv valve is a vacuum hose "
The blowby vapors that end up in an engine's crankcase contain moisture as well as combustion byproducts and unburned fuel vapors. The crankcase is sealed to prevent the escape of these gases into the atmosphere, but the vapors must be removed to prevent oil contamination that leads to sludge formation. The positive crankcase ventilation (PCV) system siphons these vapors from the crankcase and routes them into the intake manifold so they can be reburned in the engine.
The main component in the PCV system is the PCV valve, which is usually located in the valve cover. A hose connects the PCV valve to the intake manifold. A second hose between the air cleaner and crankcase or other valve cover (V6 or V8 applications) provides fresh air to help flush the vapors out of the crankcase. Some engines have a separate air filter for the PCV breather hose located inside the air cleaner.
Probably not read above for details.
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The PCV is hooked up correctly. Nothing altered , started running rough injector failed. after repaired started to whistle/ buz . Found crankcase drawing vacuum,enough that the oil cap is hard to remove and the engine stalls as though it has massive intake leak, nothing has been touched or altered other than a injector.I am currently a master tech, just never seen this happen,looking for suggestions, or possible known causes
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