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What is the round looking diaphram looking valve exiting the fuel rail?

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I have no idea what vehicle you are asking about so ill guess its a regulator.

Posted on May 02, 2017

Testimonial: "sorry, thought I mentioned it as 2000 jag xk8. I realize it has the vacume operated regulator valve mounted on the fuel rail, this valve (maybe diaphram) is in the supply line to the rail. new fuel pump and filter but still have trouble getting more that 38psi"


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How to check gas pressure on 2003 ford mustang

Go to advance look at tire pressure gauges
up by check out one shold be round like a tack
have a chrome stim sticking out bottom an the
round part look like a tire on outside buy it.
now pop hood follow fuel line to injector rail
you should see a steem like on a tire try to
use gauge on it with ingniton on not running
if it don't work you can unscrew the inside of
tire presser gauge valve on the inlet an the same
on the fuel rail an put a 3/8's hose with clamps
between the too fuel rail check valve an tire
gauge, now u can check pressure with car running
or just with key on. If you have any probs let me know
an I will come up with somthn else I have done this
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Jun 14, 2014 | 2002 Ford Mustang

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1998 nissan maxiam running rough dumping fuel

sounds like a prob. in the fuel
should have a vacuum operated valve in fuel rail.
on top of the intake you should have a fuel line, it has
fuel injectors connected to it. in the return line you will have
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Feb 24, 2013 | 1995 Nissan Maxima

1 Answer

Locate fuel volume regulator 1999 honda civic

EFI fuel pressure regulators come in various shapes and sizes but their purpose is the same- to hold the fuel pressure at a certain differential above the intake manifold pressure. The inner mechanism usually consists of a sealed diaphram chamber, a spring, a diaphram, bypass valve and a manifold pressure reference port. The valve is connected to the diaphram and the spring pushes against the diaphram from the manifold pressure side. The spring pressure determines the static fuel pressure. If there is vacuum on the port, say at idle, this reduces the effective spring pressure acting on the diaphram and reduces the fuel pressure under vacuum conditions. If there is pressure on the port, such as under boost, this effectively increases the spring pressure, thus fuel pressure.

Most OE regulators use a one to one ratio. At one psi of boost, it would add one psi of fuel pressure. This way there is always a constant pressure differential across the fuel injector. Most regulators have a static pressure of between 38 and 44 psi. The fuel pump always puts out an excess of fuel volume. The regulator controls the pressure in the fuel rail by bypassing any fuel not used by the engine back to the fuel tank once the control pressure is met. At idle, perhaps 95% of the fuel delivered to the fuel rail is returned to the tank. At full power, perhaps 5% to 50% of the fuel delivered is returned back to the tank. Fuel is generally routed from the pump to one end of the fuel rail which feeds the injectors. The regulator is usually mounted on the opposite end of the rail. This arrangement allows any hot fuel in the rail to be immediately purged back to the tank after a hot start to reduce vapor lock and fuel boiling. A similar arrangement should be used if you are fabricating your own fuel system.

Rising Rate Regulators Some aftermarket companies produce fuel pressure regulators which have a ratio of higher than one to one. These are intended for use mainly on engines which were not factoryturbocharged. Because the fuel injection system was never designed or mapped for the increased levels of airflow, fuel flow and manifold pressure, these regulators attempt to supply increased fuel under boost by vastly increasing fuel pressure. This is a bad idea for several reasons:

1. Fuel delivery varies as the square of the fuel pressure so you need 4 times the pressure to double the flow, say 160 psi in most cases.

2. The fuel injectors, hoses and fuel pumps were never designed to operate at this pressure. Pump life is severely reduced, injectors may not operate properly leading to a lean out condition and a component may fail causing a fuel leak and fire.

3. Fuel delivery under boost is now under the control of a mechanical device rather than the ECU so mixture control is crude at best.

The proper course is to use a system designed for turbocharged operation with appropriately sized injectors for the job. The OE regulator in most cases is well capable of controlling the pressure and because you can flow a lot of fuel through a 5/16 hole at 40 psi, they are entirely adequate up to 500 hp in most cases. There is no need to install larger fuel lines or massive regulators for most applications. Most aftermarket regulators are not required and a waste of time and money for street applications. They might be required at extreme hp levels on race applications or those using methanol where higher fuel flow rates demand larger lines and regulator passages. The fuel pump may have to be upgraded if the power levels are increased substantially over stock however.

Oct 21, 2012 | 1999 Honda Civic

1 Answer

Car wont start and i have fuel pressure to the bleeder valve on fuel rail but it wont fire.I replaced fuel pump and filter recently.But when I spray starting fluid into air filter it will fire .What could...

check your fuel pressure regulator its location should be on the fuel rail.Pull vacuum hose off regulator if fuel drains out of it then the diaphram is bad. Hope this helps!!

Apr 20, 2011 | 1994 Oldsmobile Ninety Eight Regency

1 Answer

We replaced the fuel filter and the fuel pump is kicking on, the engine is cranking but it won't start. we are not getting any gas to the engine.

try bleeding it off on teh fuel rail.on this line is what looks like a tyre valve and taking the cap off reveals a valve unlike a tyre valve ?? pus it in with ignition on to see if you have fuel first ,then if still not starting then look at the round valve on teh end with a rubber vacumn pipe going to it make sure that this pipe is good and not perished and split as it will never start

Feb 14, 2011 | Oldsmobile Alero Cars & Trucks

1 Answer

Cant find where the fuel line connects to the engine

If you find your fuel rails there should 2 lines.One is attached to the pulsation damper and feeds into the fuel rail which is usually in the front and on the top of the engine.The fuel then exits through the fuel rail,out the pressure relief valve and back to the tank.Most of your fuel lines are marked feed and return on the fuel hoses.If this doesn't work for you you can raise and support the front end .If you look on the frame on the driver side you should see the fuel lines that run from your fuel tank to your fuel rail or TBI (Throttle Body Injectors).Hope this helps you find it.

Feb 12, 2011 | 1997 Chevrolet Malibu

1 Answer

Fuel pressure regulator. Where is it?

Hi welcome to fixya. Well if you know the basics of an engine and know what the intake manifold and carburetor and or fuel injectors look like and are located, youll find this a simple task. Looking at the engine intake manifold where the fuel line comes into the fuel rail witch then disperses the fuel to the injectors, you will see a metal round diaphram looking component. That my friend is your fuel pressure regulator.

Dec 31, 2010 | 1995 Mitsubishi Mighty Max

1 Answer

Wanting to know where the fuel pressure contral valve is?

Hi, The fuel rail pressure regulator is mounted on the left hand side of the engine, just above the left valve cover , next to the intake manifold. It looks like a small round metal can, with a vacuum hose going to it

Sep 08, 2010 | 2001 GMC Yukon XL

1 Answer

Fuel tank selector valve

Black plastic with round screw off bottom with lots of line's coming in and going out, it is on the inside frame rail just behind driver.

Mar 30, 2009 | 1995 Ford F150 Styleside Regular Cab

1 Answer

Floods out fuel pump is fine intake gaskets have been replaced can it be a fuel pressure regulator

hello that is what this problem sounds like possible internal diaphram rupture what i would do take a fuel pressure reading at the fuel rail at the shrader valve looks like a valve stem compare with specs for allowed pressure for your vehicle goodluck please rate

Sep 19, 2008 | Buick Park Avenue Cars & Trucks

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