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Bringing fuel pressure down!


rayaapp2

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Well I am finishing up a 71 240z turbo swap. My fuel pressure went to the end of and past a 110 psi guage. I found a pluged check valve on the return line. That brought it down. Now the car starts. But After about a mile down the road the plugs foul, esp on deacceleration. Then the car will refuse to start for an hour. err. I don't know what pressure it is running at now. I don't have a meter. The other was borrowed. I guess I have a couple of choices. Get a new 99buck pump from the store, or find some sort of pressure regulator. I was thinkin pressure reg. Would that work or not. I understand that it is necissary for pressure fluxuation between 35-50psi. Am I stuck with finding a new pump? Thanks for any ideas.

ray

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Then without the appropriate diagnostic tools, you are going to be chasing your tail. It could be a vast number of things (leaking injectors etc, etc).

See if you can rent a FPG from the local parts store, or borrow that first one again.

Tim

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Well I am finishing up a 71 240z turbo swap. My fuel pressure went to the end of and past a 110 psi guage. I found a pluged check valve on the return line. That brought it down. Now the car starts. But After about a mile down the road the plugs foul' date=' esp on deacceleration. Then the car will refuse to start for an hour. err. I don't know what pressure it is running at now. I don't have a meter. The other was borrowed. I guess I have a couple of choices. Get a new 99buck pump from the store, or find some sort of pressure regulator. I was thinkin pressure reg. Would that work or not. I understand that it is necissary for pressure fluxuation between 35-50psi. Am I stuck with finding a new pump? Thanks for any ideas.

ray[/quote']

 

If the pump was making 110psi while deadheaded, it's probably not broken, although stock pumps should have an internal pressure limiter set to around 65psi (assuming stock turbo pump).

 

With that much pressure, you may have damaged the FPR. You DON'T want just any pressure regulator. There are several regulators that can work in this application, but if you don't know how to tell, you should stick with the stock regulator - it will be fine for your application. You really need to get a pressure gauge back on it and see what your fuel pressure is. Is the vacuum source hooked up to the regulator?

 

On the "won't restart for an hour" part - how hot is it there (ambient temps), and what kind of fuel are you using - does it have ethanol or methanol in it? This sounds suspiciously like vapor lock.

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I would suspect the pressure regulator. You should also check and make sure the head temp sensor is not disconnected. That will all but kill one of those engines. JWT fixed that on my ecu mod, so now it is not so rich.

 

You can get a gauge at an autoparts store, and I have one mounted in my engine comparment all the time. You never know when you will need it. It is a required diagnostic tool for efi. Time to open the wallet.

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