Fuel pressure regulator question.
Thread Starter
Instructor
Joined: Oct 2002
Posts: 116
Likes: 0
From: Seguin Texas
Fuel pressure regulator question.
I installed an adjustable fuel pressure regulator. When monitoring the fuel pressure with the vacuum line connected, what should happen to the fuel pressure when I rev the engine? Mine drops about 10psi. I thought the pressure should increase with more throttle. I may not have the vacuum line in the correct place.
85 Corvette
85 Corvette
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Possibly your pump, sock, or fuel filter aren't up to the task. Compare the fuel pressure with the engine idling, first with the vacuum hose connected and then with it disconnected. Disconnected, the pressure should be about 10 pounds higher. If it is, the problem isn't likely with the regulator.
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Instructor
Joined: May 2004
Posts: 163
Likes: 0
From: machesney park il
Originally Posted by CFI-EFI
Possibly your pump, sock, or fuel filter aren't up to the task. Compare the fuel pressure with the engine idling, first with the vacuum hose connected and then with it disconnected. Disconnected, the pressure should be about 10 pounds higher. If it is, the problem isn't likely with the regulator.
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Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Originally Posted by Swirk
I run my AFPR without the vacuum line attached.
On a stock FPR it adds a few PSI fuel, little performance mod, but with an AFPR it's not needed.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
That doesn't seem like much, but at least it's going in the right direction. Is the engine pulling good vacuum? Any vacuum leaks? The pressure SHOULD increase, when the vacuum drops, as yours does when you disconnect the vacuum at idle. Other than observing the pressure dropping when you rev it, are you experiencing any problems? Possibly the fuel pressure drop you noticed, was after the throttle was closed and the vacuum increased.
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