What should I look for if I am not getting 12v to fuel pump when I Turn the key to start. I only get the 12v if I open the air box.

Asked by Nov 15, 2017 at 04:25 PM about the 1976 Datsun 280Z

Question type: Maintenance & Repair

3 Answers


There are a set of points in the Vane Air Flow box, you need to make sure the vane moves when you crank the engine, these can get dirty over time, if it does move then you have to carefully remove the plastic cover to gain access to the electronics, then you can see if the points need to be adjusted or if the meter just flat out needs replaced due to worn out grid and burnt off points. HTH

Thank you (tennisshoes) for the response to my first question. The service manual say that the points in the air flow meter is a safety only makes the circuit when the engine is running. The key when turned to the start position should power the fuel pump. Opening the Air flow meter will power the fuel pump. I can't tell if the wire from the ignition switch (in the start position) goes directly to the fuel pump.


Unlike Amercian units these do not pressurize the system when you turn on the key to crank position, the computer need to see the engine in crank mode and some kind of air flow before the pump is turned on, the vane air flow is very sensitive to any kind of air movement, I have been able to save a few of these by using a no residue electronic cleaner. If your uncomfortable with opening the vane air box, some shops can open it and make the cleaning and adjustments, unless your in a emissions state then no one will touch it, only repalce is all they will do.

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