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Fuel check valve or leaky injectors?

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Old 09-29-2013, 08:07 PM
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Default Fuel check valve or leaky injectors?

I've got a 96 XJ and it's had the issue of not starting on the first, or maybe even the second crank. I already know what's causing the issue but does anyone know if it sound like leaky injectors or the check valve.
Thanks
Old 09-29-2013, 08:44 PM
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Originally Posted by pdowty68
I've got a 96 XJ and it's had the issue of not starting on the first, or maybe even the second crank. I already know what's causing the issue but does anyone know if it sound like leaky injectors or the check valve.
Thanks
Is this a test?
Old 09-29-2013, 11:07 PM
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Originally Posted by pdowty68
does anyone know if it sound like leaky injectors or the check valve.
Yes.
Old 09-29-2013, 11:11 PM
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Why do you ask if you know? Get a dual gauge fuel pressure tester that can isolate the system so you know what side the leak is on. Or pull the fuel rail, set it on paper towel to see if it is the injectors that are leaking.
Old 09-30-2013, 06:16 AM
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Have you had the battery tested?
Old 09-30-2013, 07:33 AM
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Originally Posted by Turbo X_J
Is this a test?
Yes. And you failed. Do you leave your crystal ball on a shelf on Sundays for a day of rest? LOL.
Old 10-02-2013, 12:33 PM
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Ok, I'm sorry to bother everyone for what seems like a question I answered myself, but what I meant by "I already know what the problem is" is that I think it's either the check valve or the injectors. I was asking because I was wondering if anyone else had this situation, and if anyone knows specifically what it is.
I just said that to partially answer the question because I thought that would make it easier to understand what's going on.
Sorry for the trouble,
Paul
Old 10-02-2013, 12:39 PM
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No trouble. We just thought it was funny. It could be either. Have you been able to figure out which one it is?
Old 10-02-2013, 12:47 PM
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Nah, not yet, that's why I came here. I try to do as much as I can before I come here and annoy everyone for stupid, simple issues. I know we're all a community here blah blah, but I don't like to bother people with stupid questions when there's people with bad problems on their dd jeep, and they can't get to work...etc those are the important questions, those should be answered first.
Old 10-02-2013, 01:30 PM
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You can isolate the problem if you have a fuel pressure gage.

1. Connect the gage at the fuel rail and start the engine. The gage should read 49 psi plus or minus 2 psi (for my 96 XJ 4.0 anyway).

2. Turn the engine off and immediately clamp the fuel line just ahead of the fuel tank. Watch the pressure gage and see how long it takes to lose pressure.

If the pressure remains at 49 psi for an extended time then the problem is in the tank - probably the check valve. If the pressure falls below 49 psi fairly rapidly then the problem is in front of the tank - probably a leaky injector.

In my case the fuel pressure would drop from 49psi to zero within 30 minutes after sutting off the engine. If I clamped the line it will hold 49 psi for hours. I concluded the problem was the check valve. I installed an “in-line” check valve in the fuel line near the fuel filter and solved the problem. At $10 it was much cheaper and easier than replacing the fuel pump.

Hope this helps.
Old 10-02-2013, 01:38 PM
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I was told clamping the fuel line will cause it to crack..remove the injectors and fuel rail and see if the injectors leak on a paper towel
Old 10-02-2013, 02:40 PM
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Originally Posted by HS00XJ
I was told clamping the fuel line will cause it to crack..remove the injectors and fuel rail and see if the injectors leak on a paper towel
The rubber line? Nah. Not unless it's about to fail anyway.
Old 10-02-2013, 03:11 PM
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Originally Posted by cruiser54

The rubber line? Nah. Not unless it's about to fail anyway.
mine feel

Fuel check valve or leaky injectors?-forumrunner_20131002_161150.jpg

plastic coming from gas tank.mines a 2000
Old 10-02-2013, 03:14 PM
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Originally Posted by HS00XJ
mine feel

Attachment 214508

plastic coming from gas tank.mines a 2000
Well, you're not the original poster, are you? You're the thread jacker.
Old 10-02-2013, 03:30 PM
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Originally Posted by cruiser54

Well, you're not the original poster, are you? You're the thread jacker.
just tring to save his fuel lines dude whatever im out of this thread like a fat kid in dodge ball


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