BunnySlippers Posted August 9, 2009 Share Posted August 9, 2009 I have a '75 280Z that was running decent, and now doesn't. I was having hard start issues. The fuel rail wasn't holding any pressure after sitting for a few minutes. I would have to crank it for a while until it had full fuel pressure again. So I replaced the FPR and new fuel hoses on the rail, but not on the injectors. Found that the old FPR was leaking into the intake manifold. Now when I try to start it it wont do it on its own, after much cranking I pulled the plugs and they were covered in gas. Replaced the plugs and got it started by pressing the pedal, it runs like that, but will not idle at all, and smokes like crazy. It's getting WAY too much fuel. For shits and giggles I even tried rutting the old FPR back on, same thing. Can the fuel pump break in a manner that delivers too much fuel? I was planning on getting that rebuilt soon anyhow. But i want to rule out anything else first. All I disconnected was the fuel injectors and the fuel lines. Advice, opinions, ridicule? Thanks guys. Quote Link to comment Share on other sites More sharing options...
Challenger Posted August 9, 2009 Share Posted August 9, 2009 How was the FPR leaking into the manifold? Check your fuel injectors. If you had a injector stuck open it would do things similar to what you explain. Quote Link to comment Share on other sites More sharing options...
BunnySlippers Posted August 10, 2009 Author Share Posted August 10, 2009 The vacuum port on the FPR angles down into the intake manifold on the 280Z. The seals in the FPR went bad, and are leaking fuel into the intake manifold vie pressure from the fuel rail. Quote Link to comment Share on other sites More sharing options...
Challenger Posted August 10, 2009 Share Posted August 10, 2009 Into, or onto? The gas isnt going Into the inside of the manifold is it? Quote Link to comment Share on other sites More sharing options...
BunnySlippers Posted August 10, 2009 Author Share Posted August 10, 2009 Yes, the old FPR was leaking fuel into the intake manifold. There is a vacuum hose leading from the intake manifold to the feel pressure regulator. The seals in the FPR went bad and were leaking fuel right into the intake manifold. But I do not see why you are pursuing this avenue. That part has been replaced. Quote Link to comment Share on other sites More sharing options...
Challenger Posted August 10, 2009 Share Posted August 10, 2009 Alright, sorry I wasnt understanding how it got into the manifold. I thought you meant it was just leaking onto the manifold. My bad. Still as I mentioned, check the fuel injectors. Another thing to check is the return line to the tank. There was a recent post where there was an obstruction in the return line in the tank and it was causeing really high fuel pressure. You can check it with an air compressor as well as visually. Quote Link to comment Share on other sites More sharing options...
zedman240 Posted August 10, 2009 Share Posted August 10, 2009 Just a guess but you could have injector/s stuck open? Either way like you said, you are getting too much fuel. If you have a fuel pressure gauge, plumb it in and see what it reads. Also, when the engine is off, see how long it holds pressure in the line. Quote Link to comment Share on other sites More sharing options...
zedsn Posted August 10, 2009 Share Posted August 10, 2009 Hi, another posibility is I believe that there is an adjustable fuel pressure regulator mounted next to the fuel pump on the back bracket. Maybe try to adjust that or you might have to replace it? Quote Link to comment Share on other sites More sharing options...
BunnySlippers Posted August 12, 2009 Author Share Posted August 12, 2009 So I'm pretty sure it is the injectors now. All I did was pull the rail off and put it on the bench to replace the FPR and put the rail back on. But stranger things have happened. Ordering a set of injectors in the next few days. Hopefully that will fix it. As far as I know the part that looks like a pressure regulator next to the pump is a fuel damper. It smooths out the pulses from the pump. Quote Link to comment Share on other sites More sharing options...
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