Guest Anonymous Posted July 2, 2002 Share Posted July 2, 2002 Whenever i turn over the car (try to)the fuel press regulator zero'z out.... It stays a constant 40psi prior to start-up. Tried to let it sit for a few minutes thinking it wasnt getting enough fuel through the lines, didnt work. Now i know theres some one on here with a logical answer!! please help, franklin p.s. 550cc injectors, fuel pump supposed to be good for 800hp. And SDS, will give out parameters if this might be the cause.... Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 3, 2002 Share Posted July 3, 2002 bump... Quote Link to comment Share on other sites More sharing options...
RB30-ZED Posted July 3, 2002 Share Posted July 3, 2002 So you say the pump works when you switch the ignition on and runs up to 40psi, and drops to zero as you crank the engine. Have you checked the pump is still getting battery voltage as you crank it? Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 3, 2002 Share Posted July 3, 2002 I assume this is an early Z? When you crank your car there is only 1 wire that remains hot and that is the one going to the coil. All others are disengaged to give the starter all the power. You need to locate this wire and use it to kick on a relay for your pump. This will solve your problem. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 3, 2002 Share Posted July 3, 2002 Hells ya! why didnt i think of that! So fuel pumps are supposed to stay even throught start-up?? thanks, franklin Quote Link to comment Share on other sites More sharing options...
Supra510 Posted July 3, 2002 Share Posted July 3, 2002 Yes. You must have fuel pressure to the injectors while the engine is turning over before start up otherwise no fuel--no start. I used an oil pressure switch to turn my pump on (i thought) and off--works for off but I had to,(as stated in an above post) run the hot wire to a relay to run the pump as the starter was turning over. The oil pressure switch alone took too much cranking as it needed to buuld oil pressure before the switch would turn on. Anthony '71 510, 91' Toyota Supra Turbo engine Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 5, 2002 Share Posted July 5, 2002 Well, your fuel pump should have some sort of check valve so that pressure does not drop instantly, but it seems that yours does not. My system will hold pressure for some time, but the Electromotive keeps my pump running while starting. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 5, 2002 Share Posted July 5, 2002 Well that solved that problem. I just simply hard wired it to the battery with a huge inline fuse, and a switch. Starts up no-problem!!!! I love this board. thanks, franklin Quote Link to comment Share on other sites More sharing options...
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