For how long pressure on fuelrail?

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wim hoppenbrouwers

NAXJA Forum User

Location

Netherlands europe

• Dec 11, 2007

• #1

Hallo, I did some maintenance on the fuelsystem of mine 92. I swapped the quickconnectors for fuelhoses with clamps (HP). renewed fuelfilter with the small hoses. But I wonder, for how long is the pressure in the fuelrail present?
When I open the checkvalve after 6 hours,there is no spray of fuel. Is this normal or is it the age (of the car)? Thanks in advance. :wave1:

 

91Woody

NAXJA Forum User

Location

Manchester, NH

• Dec 11, 2007

• #2

I will be the one to ask the obvious question; Did you turn your ignition on the engage the fuel pump to re-pressurize the lines? If you did, you should have pressure.

 

SOUTHTEXASXJ

NAXJA Forum User

Location

Odem Texas

• Dec 11, 2007

• #3

91Woody said:

I will be the one to ask the obvious question; Did you turn your ignition on the engage the fuel pump to re-pressurize the lines? If you did, you should have pressure.

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X2 /once the system has been released there wont be any pressure until you turn your key on to power the fuel pump and presserize the system.

 

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wim hoppenbrouwers

NAXJA Forum User

Location

Netherlands europe

• Dec 11, 2007

• #4

Thanks for th replies. I do understand that when I turn the key, the pump will building up pressure and when I turn the key off, the pressure is going away after some time? But how long? Is it important that the pressure will be present for some time? Is there a returnvalve in the pump?

 

91Woody

NAXJA Forum User

Location

Manchester, NH

• Dec 11, 2007

• #5

I have never opened mine up after sitting that long. Are you having issues starting your Jeep or is it just curiosity that you are asking about the "six hours later"?
I have not read into it that much but i would suspect that the fuel lines are not under load at all times, the fuel will release itself back into the tank. When you engage the ignition again, the fuel pump will again pressurize the lines.
I know someone will correct me if I am wrong. :twak:

 

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wim hoppenbrouwers

NAXJA Forum User

Location

Netherlands europe

• Dec 11, 2007

• #6

Thanks. I do now understand more. I had the idea, that mine pump was leaking and didnt hold pressure. I do have sometimes doubts about parts of mine car. It.s from 92, so it.s having a lots of gremlins.:repair:
Dealers are very exspensive in Holland(Europe). But most of all,the problem is that old cars are not interesting for them. Technical Knowledge of XJ Jeeps is very low. Greetings

 

McQue

NAXJA Forum User

Location

Plainville, Connecticut

• Dec 11, 2007

• #7

I know your vehicle is older...but here is what I can tell you about a 2001 XJ...

Connect a fuel pressure test gauge to the fuel rail test port. Start engine and bring to normal operating temperature. Normal operating pressure should be 339 kPa +/–34 kPa (49.2 psi +/–5 psi). Shut engine off. Pressure should not fall below 30 psi for five minutes.

 

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wim hoppenbrouwers

NAXJA Forum User

Location

Netherlands europe

• Dec 11, 2007

• #8

Thanks folks and McQue, I will get me a fuel p. test gauge tomorrow.

 

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wim hoppenbrouwers

NAXJA Forum User

Location

Netherlands europe

• Dec 21, 2007

• #9

wim hoppenbrouwers said:

Thanks folks and McQue, I will get me a fuel p. test gauge tomorrow.

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Hallo I am back. Bying a fuel inj. Pumptester with gauge, isn't so easy as it looks. In Holland (Europ) it is very expensive. When I look to the site of Harborfreight.com i wil see a tester of USGeneral (92699-4VGA).
Can someone tell me his expirience with these tester. Will it work with the Schradervalve? Is there no trapped air in the hose to give a wrong reading?
By the very expensives there is a valve under the gauge to let escape air.
:wantyou: