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help please! (fuel/vacuum system)


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im having problems with some kind of valve on the drivers fender under the break master. its on a 73 datsun 620 pickup l16. i know it needs to be hooked to vacuum but i cant figure out how or where the truck had a webber on it when i bought it and now i have a rebuilt stock hitachi. fuel system is sucking air and this is the only thing i cant figure out. please help!

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Sounds like the flow guide valve. It has a line to the gas tank for venting fumes, one to the large crank case vent tube coming straight out of the block through the exhaust manifold (also connected to the PCV valve) and a line to the air filter holder.


When the engine is off tank fumes and gas fumes from the air filter drop down and enter the engine crank case and are stored there. When the engine starts the PCV valve on the intake sucks all fumes into the motor to be burned.

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thanks i got all that figured out. now im having trouble with my vacuume lines. the EGR valve and all other smog stuff was deleted by the previous owner. all i have for vacuume is my advance on the destributor, one off the carb and one on the intake. any suggestions?

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Plug the intake unless it's for brake booster.

The carb should have two ported outlets one for EGR the other for vacuum advance on the distributor. The line closest to the front of the carb is for the vacuum advance.

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