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Old 09-20-2012, 06:24 PM   #61
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Originally Posted by jleahy View Post
I spoke to my jeep mechanic today and he told me the FPR is located at the fuel outlet under the hood and that the check valve is located on top of the tank. I have a 4.0 and am wondering if it's possible that just the FPR could be bad vs. the check valve or as someone posted, it would have to be both? Can someone clarify please?
Older Jeep models with the 4.0L engine ('95 and earlier) did have a FPR under the hood. Your FPR is at the tank, but there is no "check valve" per se in the FPR. There is a relief mechanism which tends to leak with age, allowing the fuel supply line to drain back into the tank via the relief passage.

There is a check valve in the pump assy, but the FPR is your most likely culprit. In the vast majority of cases, replacing the FPR will solve a "slow start" condition.

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Old 09-20-2012, 07:07 PM   #62
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You're just being argumentative... that "relief mechanism" is a relieve valve (valve is the word you used for it elsewhere) which also serves as a check valve. When it leaks, it allows the fuel to drain past it and back down into the gas tank... as you even described in another of your posts today. Reasonable people who aren't just trying to be argumentative simply call it an anti-drainback valve since when it works properly, it prevents fuel from leaking around the FPR and back down into the gas tank.

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Old 09-20-2012, 07:35 PM   #63
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You're just being argumentative... that "relief mechanism" is a relieve valve (valve is the word you used for it elsewhere) which also serves as a check valve.
Despite FSM wording to that effect, the relief valve does not truly serve as a check valve. If it did, a regulator that flows backwards (not the same as leaking though the relief valve) would be as defective as you claim it is.

Fuel entering the regulator has two ways to get out. One of those options should be unavailable below about 50 psi. Unless it leaks.

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Originally Posted by Jerry Bransford View Post
Reasonable people who aren't just trying to be argumentative simply call it an anti-drainback valve since when it works properly, it prevents fuel from leaking around the FPR and back down into the gas tank.
Knowlegable people understand that the anti-drainback valve is in the pump assembly, not the fuel pressure regulator.

Reasonable people don't invent theories that happen to fit the circumstances and them preach them as gospel.
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Old 09-20-2012, 07:44 PM   #64
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Go argue with the FSM.
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Old 09-20-2012, 07:48 PM   #65
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Go argue with the FSM.

Not everything in the FSM is correct.
Fact is, the FSM does not state that there is a check valve in the FPR.
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Old 09-20-2012, 07:52 PM   #66
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The FSM is wrong? Uh huh, whatever you say.

Edit: Oh nice edit to delete where you just claimed the FSM was wrong.
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Old 09-20-2012, 07:59 PM   #67
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The FSM os wrong? Uh huh, whatever you say.
I am not the individual telling people that their regulators are defective because they pass air both ways. Or that air is not viscous enough to actuate the "check valve."
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Old 09-20-2012, 08:03 PM   #68
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Is this guy ^ always arguing with you Jerry?
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Old 09-20-2012, 08:06 PM   #69
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Is this guy ^ always arguing with you Jerry?
I am not arguing with Bransford. I am just telling him in no uncertain terms that he is wrong.
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Old 01-20-2013, 12:03 PM   #70
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Originally Posted by Jerry Bransford View Post
It can be done in an hour and you only need basic hand tools and a jack to do it. Just make sure the tank is nearly empty before you start the job.

This is what the top of the tank and fuel pressure regulator looks like, which just snaps into place, I replaced mine earlier this year.

Great post up Jerry,thanks as iam having some problems with mine i think as well.
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Old 06-24-2013, 06:55 PM   #71
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Okay, I have been having similar issues. Just ordered an new FPR and hopefully I can get-R-dun as soon as the part comes in. Thanks for the info Jerry. I will post the results of my efforts.
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Old 07-09-2013, 12:34 PM   #72
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Okay, I have been having similar issues. Just ordered an new FPR and hopefully I can get-R-dun as soon as the part comes in. Thanks for the info Jerry. I will post the results of my efforts.
Installed the new PFR over the weekend and it works like a dream. Fires right up! Took around 3.5 hrs total.
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Old 08-11-2013, 05:01 PM   #73
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So I just changed my FPR and still have the problem to crank the ignition a few times to get it started. And by a few times i mean like 20-30 minutes. Are there any other solutions? I am going to replace the spark plugs to see if that helps even though I just changed them not to long ago. I'm out of ideas on what the problem is. Could it be the crank sensor? Any help would much appreciated!
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Old 08-11-2013, 05:33 PM   #74
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ok, so.... your fuel pressure was low... that means the fuel pump itself is gone/going.
if your fuel pressure is high it means your regulator.
normal pressure is 45-54 psi. <according to the haynes> I replaced my whole fuel sending unit with one from spectra premium. Got it off amazon.com. cost me 120.00 free shipping. comes with a new everything. even the rubber gasket that seals the ring to the tank. I had to replace my tank skid, so I replaced that while I was down there too. also the straps. <looking back I should have done the rear track bar too >
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Old 08-11-2013, 06:52 PM   #75
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My Spectra fuel pump & FPR lasted about a year before it started letting the fuel drain down out of the fuel rail. I now have to cycle my ignition switch 6-8 times to get fuel back up to the fuel rail so the engine will start. I installed the Spectra out of low funds desperation, I'll be replacing it with an OE Mopar asap.
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Old 12-28-2013, 06:03 PM   #76
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This thread is great. I have a 95 and having this exact problem. Does anyone know if the FPR on the 95 is also in the tank or is it up front? My problem is getting worse so I will need to tackle it now. Thanks this has been very helpful.
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Old 12-28-2013, 06:33 PM   #77
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Not being a YJ guy, I believe your '95 4.0L has its FPR on the fuel rail. I wish the TJ's was!

Yours should look like this...
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Old 12-28-2013, 06:41 PM   #78
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Just because you can blow through both sides tells me that's not enough pressure to close the check valve. My 97 Tj is doing the same thing. I will most likely replace pump and reg assy.
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Old 12-30-2013, 10:15 AM   #79
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Check part 24 from this link. Please correct me if I'm wrong but a filter you can blow thru both end.

Fuel System Parts - Tank Fuel, Gas Cap, Injector Fuel, Throttle Body, Idle Speed Motor and Sensor Throttle Position for your Jeep Wrangler TJ by Morris4x4
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Old 12-31-2013, 07:46 AM   #80
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Just because you can blow through both sides tells me that's not enough pressure to close the check valve. My 97 Tj is doing the same thing. I will most likely replace pump and reg assy.
There is no check valve in the FPR. That check valve is in the fuel pump. The drainback problem usually occurs because the pressure relief valve fails to seal completely and allows fuel to bleed back into the tank. In theory, the fuel pump check valve could fail with the same result, but the odds severely favor a failed FPR.

Despite claims to the contrary by folks who know a little about a lot, there is no mechanism in the FPR itself that provides for one-way flow. Fuel will flow with equal ease in both directions, I guarantee it.
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Old 12-31-2013, 08:07 AM   #81
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Thanks Jerry this has saved me a ton of money and time. I apreciate the reply and the help.
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Old 12-31-2013, 08:26 AM   #82
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JWT, the rail-mounted FPR is much less problematic than the TJ version. (I have a 26 year-old XJ with the original regulator still working fine.)
If you haven't yet solved your problem, you might check to see if your YJ regulator is passing gasoline to the vacuum port. That would be one clear indication of failure.
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Old 03-06-2014, 09:17 PM   #83
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Did you ever solve your problem? Mine was doing same thing it only did it if the jeep sat over night or for a few hours but as soon as i replaced with a new fuel pressure regulator (which blew air through both sides) it got worse and does it every time i try to crank it pretty much. also when i hooked up a fuel pressure gauge the only time it held pressure was when the jeep was idling and it held at about 50, if i just turned the key to on position is would only reach about 10 and instantly fall back down. Also when i turn the vehicle off the pressure instantly falls from 50 to 0.

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