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The two wires going to the fuel pump on my 1976 280z are green and black, the green wire is only showing fire when the car is starting. but neither wire is hot when not in starting position. The fuel pump runs when starting the car but as soon as I stop cranking the car no fire to pump.I took the fuel line loose to the engine and try to start the engine and see if the the pump would pump gas out the line,it didn't.I made sure there was plenty of gas in the tank for the pump to pick up, I would geatly appreciate any help offerd.
 

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this is kinda hard to explain over the internet but i will try...when i converted my 240z to a 77 injection setup i had trouble getting power to the fuel pump ...so i just put a new wire to the pump that was only hot when the key was on...later i found out that inside the air flow meter there is a contact that opens when the car is started and allows power to goto the fuel pump...if you know anything about an air flow meter you will kinda know what im talking about...its kinda like a wiper that runs across an elecrical board...well when this wiper returns to the off position..(when the car isnt running)...it makes a contact that shuts off power to the fuel pump...so if the car stalls or you were to get in an accident it would cut the power to the pump when the engine dies...this way gas wouldnt flow all over the place....im thinking that you have a problem there...that is if everything else is in good condition....on the top of the flow meter there is a black plastic cap..its usually gled on...pop it off and make sure everything in there is working...slide the wiper back and fourth ..also see about the contact that i was talking about is opening when in the bottom position...or if u have another flow meter pop it in and see if this helps...i hope i made sense here..lol...bigjim
 

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Most fuel injected cars will not run the fuel pumps until the engine is actually rotating. On the 75/76 Z cars this is controlled by a switch in the air flow meter. When the car is cranked there is enough engine vacuum to open the flap and there by activate the switch. On the 77-83 cars the pump is triggered by oil pressure. To check your pump pull the rubber section of the intake between the air cleaner and the air flow meter, turn the key to run, and have someone reach in with a finger and open the flap in the air flow meter. You should hear the pump start up.

Hope this helps...............

Charles
 
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