Vacuum leak - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z
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post #1 of 3 (permalink) Old 03-29-2016, 11:17 AM Thread Starter
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Vacuum leak

Hi, I bought my first Z in the fall, and have been tinkering with it over the winter. It is a 1986 turbo model. I am hoping someone can answer my question, which is: My vacuum pump runs quite loudly without ever turning off, and I can hear a hissing sound from or near the Fuel Pressure Regulator. Is it normal for the regulator to hiss? I checked it with the ignition on, but the car not running, and with the car running as well. Thanks for your help and suggestions
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post #2 of 3 (permalink) Old 03-29-2016, 11:34 AM
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the vacuum pump is turned off and on by a vacuum switch in the tank. If you are tired of hearing it run there are two wires out the bottom to a connector. undo that pump no run. if you are into fixing it you can bench test it with a vom and a vac pump like you use for brake bleeding or a vacuum cleaner and tubing and duct tape. Mine changes state at about 15 inches of mercury. If you don't know what any of the above is/are then you need to study or just disconnect it.

the fpr has fuel passing thru it so maybe that is the hissing but my guess is vacuum leak in or around the the vacuum tank. The original vac hoses are usually shot and the best bet is to replace them all.

get the fsm from free download and it is how you best learn to repair things. the other car manuals aren't so detailed and often not correct.

86T, 350 Nismo 08 (#1415) gone but fondly remembered 81T, 83T, 83, 85T, 86T, 96TT
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post #3 of 3 (permalink) Old 03-29-2016, 11:57 AM Thread Starter
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Thank you for your help. I download the FSM,and replace the hoses first and see if that stops the hissing.
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