7MGFORCE Posted July 10, 2009 Share Posted July 10, 2009 I have an early 74 260z with a v8 convertion but I figure this related more here than the v8 forums. I got the car as a shell so I'm unsure what the problem could be. I have replace the stock pump with mallory pump but I wired it to the stock pump wires. Now when I check it I had someone crank the car but the possitive doesn't carry any charge so the fuel pump doesn't pump. The ground works. What could be wrong with? I check the fuse but none of them are for the pump. Side question which is the stock feed line on the stock tank? The top or the bottom? Quote Link to comment Share on other sites More sharing options...
Larryz 260 Posted July 10, 2009 Share Posted July 10, 2009 That pump is on a relay and does not come on until the motor gets to 500 rpm, but I had a bad relay on mine when I got the car and when I got a new one I thought I got a bad relay at frist Quote Link to comment Share on other sites More sharing options...
7MGFORCE Posted July 10, 2009 Author Share Posted July 10, 2009 That pump is on a relay and does not come on until the motor gets to 500 rpm, but I had a bad relay on mine when I got the car and when I got a new one I thought I got a bad relay at frist Oh so the pump doesn't pump until the car runs basically? Where is that relay? How do I check if the relay is good? And I change the fuel line so no fuel is on the lines or carb how do I get the fuel pump to pump and fill the lines with gas if the pump will not pump until it hits 500rpm. Quote Link to comment Share on other sites More sharing options...
langfordchuck Posted July 10, 2009 Share Posted July 10, 2009 Well, on a stock 260 there are two pumps, one mechanical on the block and one electric, which is the one you are talking about. I am not sure what v-8 you have so can't tell you if it has a mechanical fuel pump or not. The second pump on the 260 z was to deal with vapour lock problems on earlier z'ds. The FSM tells you the relay is on the pass side, on the relay panel, under the dash, on the right hand side. a little detective work will identify which relay it is. Quote Link to comment Share on other sites More sharing options...
7MGFORCE Posted July 10, 2009 Author Share Posted July 10, 2009 Well, on a stock 260 there are two pumps, one mechanical on the block and one electric, which is the one you are talking about. I am not sure what v-8 you have so can't tell you if it has a mechanical fuel pump or not. The second pump on the 260 z was to deal with vapour lock problems on earlier z'ds. The FSM tells you the relay is on the pass side, on the relay panel, under the dash, on the right hand side. a little detective work will identify which relay it is. I have a ford 5.0 motor 1990 with carb setup. It does not have a mechanical pump so I just have an electric. Do I need to wire it a certain way so the pump comes on soonerr? How do I wire this up? Quote Link to comment Share on other sites More sharing options...
Bart Hoedemaker Posted July 11, 2009 Share Posted July 11, 2009 Use a multimeter on the lines that go to the pump, to see which one gives + feed. ( Crank it over ) Quote Link to comment Share on other sites More sharing options...
7MGFORCE Posted July 11, 2009 Author Share Posted July 11, 2009 Use a multimeter on the lines that go to the pump, to see which one gives + feed. ( Crank it over ) Yes I have tried this buy what else need a possitive when cranking besides the pump. And the one that connects to the stock pump does not hold possitive current. Quote Link to comment Share on other sites More sharing options...
Bart Hoedemaker Posted July 12, 2009 Share Posted July 12, 2009 I'm a bit confused what you are trying to tell me. How many wires are going to the standard pump? Quote Link to comment Share on other sites More sharing options...
7MGFORCE Posted July 12, 2009 Author Share Posted July 12, 2009 I'm a bit confused what you are trying to tell me. How many wires are going to the standard pump? There's only two but as I states before you posted I have it wires up already. None of the two putsout possitive when cranking the engine. I know for sure ones negative as I tested it with a live wire the other holds niether ground or power. Quote Link to comment Share on other sites More sharing options...
Bart Hoedemaker Posted July 12, 2009 Share Posted July 12, 2009 Did the engine run on the standard pump? If it didn't work at all, check the relais. If that doesn't help. Pull a + line from the battery to the pump with a switch. Quote Link to comment Share on other sites More sharing options...
7MGFORCE Posted July 12, 2009 Author Share Posted July 12, 2009 Did the engine run on the standard pump? If it didn't work at all, check the relais. If that doesn't help. Pull a + line from the battery to the pump with a switch. I got the car as a shell and the previous owner said it ran before he tore it down a year b4 I purchase it. Which is the relay? I'm having trouble finding the pump relay. And I'm trying to avoid the switch idea for safety reasons. If something happen knock on wood the last thing I need is the pump to be pumping when I can't turn off the switch. Is there any live wire that only comes on when cranking and stay on only when the engines on? Quote Link to comment Share on other sites More sharing options...
7MGFORCE Posted July 14, 2009 Author Share Posted July 14, 2009 Another question is the stock pump dependent on oil pressure? I mean if the oil pressure is not connected will the pumpwork? Quote Link to comment Share on other sites More sharing options...
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