Jason280zx Posted April 8, 2013 Share Posted April 8, 2013 Hey guys, so my 83 280zx non turbo is having a bit of of an issue of high fuel pressure levels. Heres a quick summary about the car. I gave it a full tune of replacements such as fuel hoses and vacuum hoses. New filters (Oil, fuel, air) spark plugs, and wires. Dizzy cap and rotor inside, belts, oil change, and last new Fuel pump. Side note about the fuel pump, theres a wire issue with the ignition switch so the fuel pump doesnt activate, so i made a switch from the pump directly to the battery to turn it on and works fine. Now heres the problem, when i activate the switch for the pump to turn on, gas starts spewing out a hose beneath the car due to high pressure, so my question is, why isnt the fuel running through the rails and going back to the tank properly? And i believe it might be the FPR BUT my situation is different, im trying to get my car running again after i bought it from a guy who had it sitting for 5 years, and i know my car can turn on because after a try of spraying starter fluid into the intake, the motor turns over by it self. And my other question is, does the FPR only works when the car is on to allow fuel flow? Please message me y'alls thoughts and explainations of what it could be. I have done some research through the forum, but if theres a place to look deeper into, please send me the link! it'll be very helpful. Thanks guyz! Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted April 8, 2013 Share Posted April 8, 2013 The fpr is vacuum controlled. There is a line goingfrom the top of the fpr to the intake. But the fpr shouldn't just block fuel. I think that your fuel lines may be clogged. Try taking your fuel rail off and blowing compressed air through it to clear it out. Do this to your fuel lines running under the car as well. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 8, 2013 Share Posted April 8, 2013 Maybe you connected hoses backwards at the tank. Pumping in to the return line instead of the supply line. The FPR won't flow backward, so you'll end up with the 90 psi or more that most aftermarket pumps will produce. Ot it could just be a loose hose clamp. Doesn't sound like you've looked to see where the leak is. "a hose beneath the car"? Quote Link to comment Share on other sites More sharing options...
Jason280zx Posted April 8, 2013 Author Share Posted April 8, 2013 Maybe you connected hoses backwards at the tank. Pumping in to the return line instead of the supply line. The FPR won't flow backward, so you'll end up with the 90 psi or more that most aftermarket pumps will produce. Ot it could just be a loose hose clamp. Doesn't sound like you've looked to see where the leak is. "a hose beneath the car"? Well i know exaclty where it is, i just didnt want to go too much into detail, it spits out from where the fuel damper is. Quote Link to comment Share on other sites More sharing options...
Jason280zx Posted April 8, 2013 Author Share Posted April 8, 2013 The fpr is vacuum controlled. There is a line goingfrom the top of the fpr to the intake. But the fpr shouldn't just block fuel. I think that your fuel lines may be clogged. Try taking your fuel rail off and blowing compressed air through it to clear it out. Do this to your fuel lines running under the car as well. And thanks for the advise, that was my initial plan to do first before buying a new FPR. Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 8, 2013 Share Posted April 8, 2013 You might have the hoses at the rail switched, in the engine bay by the filter. That would pump directly to the return of the FPR. Note - I've only verified that an Aeromotive FPR won't flow backward, not a stock one. But I think that the general concept of regulation is the same. The fuel pushes on a much smaller area in reverse. Quote Link to comment Share on other sites More sharing options...
Jason280zx Posted April 9, 2013 Author Share Posted April 9, 2013 You might have the hoses at the rail switched, in the engine bay by the filter. That would pump directly to the return of the FPR. Note - I've only verified that an Aeromotive FPR won't flow backward, not a stock one. But I think that the general concept of regulation is the same. The fuel pushes on a much smaller area in reverse. i took a quick look back at the rails and checking for any mistakes i made, i was pretty sure i didnt but thanks to my OCD i had to check haha but i just removed my fuel rail and MAN it was a hassle! thanks for y'alls thoughts, really helped! Quote Link to comment Share on other sites More sharing options...
Josh280z Posted April 9, 2013 Share Posted April 9, 2013 Fuel pressure regulator works off of vacuum. IIRCC a loss of a vacuum will cause a rise in fuel pressure. Not saying that it's your problem, but you might check that. Also, like you said you might try a new FPR. Quote Link to comment Share on other sites More sharing options...
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