Guest 280zfast Posted April 9, 2008 Share Posted April 9, 2008 I have a 75 280z coupe, and I tested all of the pins on the ecu from the efi bible, and I tested the fuel pump while cranking and it only recieved 0.03 volts on a fully charged battery. Is this normal?? the fuel pump didn't even turn on..hell I don't think any pump would work with only 0.03 volts. tomorrow I am going to rewire the positive wire to wherever it goes I have also pulled the cover off of my efi relay to see if it was working or not and it was...one of the pin connectors to the fuel injectors was pulled out of the plastic, and that is why my injectors werent working, so I fixed that problem, and I cranked the engine to see if the fuel pump side of the relay was operational, and it was, so I'm at a loss right now as of why the fuel pump only gets .03 volts....I thought the fuel pump was supposed to get 12 volts?? right well if anyone can help me out it will be greatly appreciated I believe this is why my pump wont pump gas. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted April 9, 2008 Administrators Share Posted April 9, 2008 You're right, it wont work on .03v, and yes, the fuel pump should be running while cranking. Try this... pull the inlet boot on the AFM, turn the key to the 'on' position, and push on the AFM door. When the AFM door comes off its seat, it engages contacts to activate the fuel pump relay. You should be able to hear the pump run. Quote Link to comment Share on other sites More sharing options...
Guest 280zfast Posted April 9, 2008 Share Posted April 9, 2008 thats the other thing I did...I took the afm hose off pushed the flap open, "(I also took the case off of the relay to make sure the contacts were moving, and clicking)" And I watched the fuel pump relay click, anbd engage, but the at the fuel pump it still read 0.03 volts? I have no clue why it would read his voltage....All I know is something is not right. Quote Link to comment Share on other sites More sharing options...
Guest 280zfast Posted April 9, 2008 Share Posted April 9, 2008 and when I pushed the afm flap open, the fuel pump still didn't turn on. Quote Link to comment Share on other sites More sharing options...
Shift Posted April 9, 2008 Share Posted April 9, 2008 Bad ground? Quote Link to comment Share on other sites More sharing options...
Guest 280zfast Posted April 10, 2008 Share Posted April 10, 2008 no not a bad ground because I wired in a 12 volt switch directly from the battery to run the fuel pump temporarily, and i used the fuel pumps original ground. and the pump turned on so that eliminates any bad grounding issues. I was told that the fuel pump positive wire could be damaged, or frayed causing a short which in turn should cause the voltage to read only 0.03 volt....wel thats my thesis on that matter, so I will end up tyracing the wires tomorrow to see what the problem is. If any one has any more ideas or opinions you are welcome to help me out it is greatly appreciated. Thanks. Quote Link to comment Share on other sites More sharing options...
Shift Posted April 10, 2008 Share Posted April 10, 2008 run a continuity check on the 12v wire then Quote Link to comment Share on other sites More sharing options...
Guest 280zfast Posted April 10, 2008 Share Posted April 10, 2008 i guess thats what i'll do Quote Link to comment Share on other sites More sharing options...
woldson Posted April 10, 2008 Share Posted April 10, 2008 Just throwing this in. My ZX has a oil pressure switch that will kill the fuel pump if the engine looses pressure. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted April 10, 2008 Share Posted April 10, 2008 the 75 doesn't have that pressure switch. It changed to that style in 77 or 78 Quote Link to comment Share on other sites More sharing options...
Guest 280zfast Posted April 10, 2008 Share Posted April 10, 2008 already bought and replaced the oil pressure sender. Quote Link to comment Share on other sites More sharing options...
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